Vacuumatic Limited

George W Day

Keith J Latham

Kenneth G Dalby

The disclosure relates to sheet separating device for a stack counting apparatus including a counting head to traverse a corner of a stack and having a horizontal suction blade with a suction orifice on its upper surface for insertion in the stack and oscillatable about a horizontal axis to separate a corner of a sheet in the stack adhered by the suction port to the blade from the next sheet. A wiping pin is driven in an elongate orbit around the blade from the trailing edge thereof over the upper surface to the leading edge and along the underside of the blade to transfer a corner of a sheet adhered to the upper surface of the blade from the upper surface to the lower surface. A counting device is arranged to count the number of sheets transferred by the pin. In order to minimize damage to the stack by the engagement of the blade and pin in the stack, the path of the movement of the pin from the upper surface to the lower surface adjacent the leading edge of the blade is in a generally vertical direction after which the pin moves generally horizontally close to the underside of the blade, while the blade remains substantially horizontal and the blade tilts downwards to separate the corner of a sheet on it from the sheet above only after the pin has moved beyond the undersurface of the blade. The pin then moves over the upper side of the blade towards the leading edge thereof as the blade returns to the horizontal.

Sheet separating device for a sheet counting apparatus

The disclosure relates to an air pressure sensor comprising a first air passage, a branch passage having an opening into the air passage, a sensor in the branch passage responsive to variation in air pressure in the opening and jet means for air flow through the first passage adjacent the opening to the branch passage to create an increased depression in static pressure as compared with the remainder of the air passage to enhance the response of the pressure sensor in the branch passage when air flow through the first passage occurs. The air passage terminates in a probe having an orifice to be opened and closed by the absence of and presence of a surface in contact with the probe so that the pressure sensor indicates whether or not the probe is in contact with the surface. The arrangement is particularly suitable for counting a 'shingled' stream of sheets such as signatures, the stream passing the orifice to the probe such that the orifice is opened and closed as successive sheets pass the probe, the resulting signal in the air pressure sensor being used to operate a counting device.

Air pressure operated proximity sensor

There is disclosed an apparatus for separating sheets at the bottom of a stack comprising two contrarotating suction drum assemblies (14,15:17) and a suction pipe (18) extending between the two assemblies. In order to ensure that the edges of the lowermost sheet are fully separated from the sheet above before the sheet is extracted from the bottom of the stack, one assembly has a central suction drum (14) having suction outlets (25) and the other assembly (17) has suction outlets (29) to draw the edges of the lowermost sheet in their central regions downwardly from the sheet above. Two pairs of contrarotating double ended fingers (32) are mounted on either side of the drum assemblies to enter the stack above the lowermost sheet where the central region has been drawn downwardly and to move along the edges of the stack towards the ends of the stack to separate the edges of the lowermost sheet from the sheet above. The drum assembly (15) has two outer suction drums (15) which rotate at twice the speed of the central drum section ( 14) and have suction ports (33) activated when the fingers (32) have separated the edges of the lowermost sheet to draw the lowermost sheet out of the bottom of the stack.

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Dovercourt, United Kingdom

George W Day