Apparatus for cutting paper webs or the like

Claim 1

Apparatus for subdividing a running web of paper or the like into sections of desired length, comprising means for advancing the web lengthwise along a first path at a predetermined speed; rotary cutter means including at least one knife orbiting along an endless second path a portion of which is adjacent said first path so that the knife makes a cut transversely across the running web while moving along said portion of said second path whereby the web yields a succession of discrete sections whose length is a function of the duration of intervals which elapse between successive movements of said knife along said portion of said second path; a variable-speed prime mover for said cutter means; control means for varying the speed of said prime mover during each revolution of said cutter means so as to drive said knife at a first speed which matches said predetermined speed while the knife moves along said portion of said second path and at one of a plurality of different second speeds while the knife moves from and back to said portion of said second path, said control means including means for generating first signals denoting said predetermined speed and means for maintaining the speed of orbital movement of said knife in said portion of said second path at said predetermined speed in response to said first signals, said means for generating said first signals comprising a rotary element having equidistant indicia, means for rotating said element at a speed which is proportional to said predetermined speed and signal generating detector means arranged to monitor said indicia and to transmit said first signals at a constant frequency, said maintaining means including means for respectively generating second and third signals during movement of said knife along said portion of said second path and during movement of said knife from and back to said portion of said second path, said second signals being a function of said first signals and said maintaining means further including means for regulating the speed of said prime mover as a function of said second and third signals, said means for generating said second and third signals including a second rotary element having a first set of equidistant indicia and a second set of indicia, means for rotating said second element in synchronism with said cutter means and transducer means arranged to monitor the indicia of said second element and to respectively transmit said second and third signals on duration of indicia of said first and second sets; and means for adjusting said control means to select the second speed and hence the duration of said intervals, said adjusting means including means for varying said third signals.