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US 4,437,367 AGranted
Process and apparatus for controlling the cutting feed of band saw machines
OwnerKarl Hauserinventor
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OwnerKarl Hauserinventor
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A method and apparatus for controlling the cutting feed of band saw machines for obtaining an optimum feed rate with the same safety against straying of the saw cut, according to which the saw band is maintained continuously within the area of its teeth under a residual tensile stress (.sigma..sub.Z.sbsb.Res) adjusted at least approximately to a constant value. For this purpose, a desired value is selected for the residual tensile stress, determined experimentally under practical conditions, which is correspondingly converted in case of load conditions of the saw blade deviating from the experiment, and this desired value is compared with the actual value. The actual value (.sigma..sub.Z.sbsb.Res) is derived as a difference from the tensile stress (Z) in the critical saw band point and the bending stress .sigma..sub.B caused by the feed, to be .sigma..sub.Z.sbsb.Res =.sigma.Z-.sigma.B>0. The actual value is adjusted to the desired value by varying the feed rate; the sum total of all feed forces or the sagging angle of the saw band is selected as a measure for the actual value. As a result thereof the danger of straying is precluded and yet an economically optimal feed rate is attained in band saws.
A method for controlling the cutting feed speed of band saw machines equipped with a toothed saw band to attain an optimum feed velocity with substantial constant safety against straying, comprising the steps of empirically determining under predetermined conditions an acceptable optimum cutting force representing a desired cutting force value, calculating from said acceptable optimum cutting force the corresponding residual tensile stress in the saw band, and continuously maintaining the saw band under said residual tensile stress within the critical zone of the teeth by measuring the actual value of the cutting force, comparing the actual cutting force value with the desired cutting force value, and adjusting the actual cutting force in case of differences between the actual and desired cutting force value to thereby maintain an at least approximately constant value of said residual tensile stress and therewith obtain substantially optimum feed velocity during cutting of the workpiece.
An apparatus for controlling the cutting feed velocity of band saw machines to obtain an optimum feed velocity with substantially constant safety against straying of the saw cut, comprising a band saw machine having a toothed saw band, and control means for controlling the cutting force of the saw band to continuously maintain the toothed saw band, within a critical zone of its teeth under an at least approximately constant predetermined residual tensil stress including means for producing a signal representative of the value of the actual tensile stress in the critical zone of the saw band, means comparing said signal with a signal representative of the desired value of the predetermined residual tensile stress, and means for adjusting the actual value to the predetermined desired-value for the residual tensile stress to thereby realize substantially optimum feed velocity while preventing straying of the saw cut.
Dependencies are inferred from the claim text.