Device for detecting a bend angle upon precisely bending a metallic pipe

Claim 1

Apparatus for detecting the bend angle of a pipe having an initially generally straight portion being bent to curved form by longitudinally moving the pipe while applying a lateral force thereto in said portion, said defecting apparatus comprising: means establishing a first translationally fixed, angularly rotatable axis outside the pipe, laterally spaced therefrom and disposed generally in the imaginary plane normal to the longitudinal axis of the pipe at the juncture between where the pipe remains unbent and where the pipe is being bent; means establishing a second angularly rotatable axis on the pipe in said portion whereat the bend angle with respect to the longitudinal axis of the pipe at the imaginary plane is to be determined, the second axis being parallel to the first axis; arm means joining said first and second axes and being so mounted at opposite ends with respect thereto that as the pipe is longitudinally moved in being bent, one end of the arm moves angularly about the first axis in correspondence to the angular movement of the opposite end of the arm about the first axis due to the joining of said opposite end and the pipe at the second axis; means measuring the angular movement of said arm about the first axis; means measuring the angle between said arm and the longitudinal extent of the pipe at said second axis; and means for detecting, as the bending proceeds, the sum of: a. the angular disparity between the opposite extremes of disposition of said arm due to angular movement about the first axis; and b. the difference at said opposite extremes of disposition of said first axis of the angle between said arm and the longitudinal axis of the pipe at said second axis; as a measure of the angular disparity between the disposition of the longitudinal axis of said pipe axially conincident with said second axis, the angular amount said pipe has been bent at said second axis.

Claim 3

A method for detecting the bend angle of a pipe having an initially generally straight portion being bent to curved form by longitudinally moving the pipe while applying a lateral force thereto in said portion, said detecting method comprising: establishing a first translationally fixed point outside the pipe, laterally spaced therefrom and disposed generally in the imaginary plane normal to the longitudinal axis of the pipe at the juncture between where the pipe remains unbent and where the pipe is being bent; establishing a second point fixed on the pipe in said portion, whereat the bend angle with respect to the longitudinal axis of the pipe at the imaginary plane is to be determined; tying the rotational disposition of the first fixed point to the second fixed point, so that as the pipe is longitudinally moved in being bent, said first point is correspondingly angularly moved to maintain its angular position fixed relative to said second point; as the bending proceeds, monitoring the sum of: a. the angular disparity between the opposite extremes of disposition of said first point; and b. the difference at said opposite extremes of angular disposition of said first point of the angle between a straight line joining said first and second points and the longitudinal extent of said pipe at said second point; as a measure of the angular disparity between the disposition of the longitudinal axis of said pipe axially coincident with said second point, the angular amount said pipe has been bent at said second point.

Claim 4

A method for detecting the bend angle of a pipe having an initially generally straight portion being bent to curved form by longitudinally moving the pipe while applying a lateral force thereto in said portion, said detecting method comprising: establishing a first translationally fixed point outside the pipe, laterally spaced therefrom and disposed generally in the imaginary plane normal to the longitudinal axis of the pipe at the juncture between where the pipe remains unbent and where the pipe is being bent; establishing a second point fixed on the pipe in said portion, whereat the bend angle with respect to the longitudinal axis of the pipe at the imaginary plane is to be determined; tying the rotational disposition of the first fixed point to the second fixed point, so that as the pipe is longitudinally moved in being bent, said first point is correspondingly angularly moved to maintain its angular position fixed relative to said second point; as the bending proceeds, monitoring the sum of: a. the angular disparity between the opposite extremes of disposition of said first point; and b. the difference at said opposite extremes of angular disposition of said first point of the angle between a straight line joining said first and second points and the longitudinal extent of said pipe at said second point; as a measure of the angular disparity between the disposition of the longitudinal axis of said pipe axially coincident with said second point, the angular amount said pipe has been bent at said second point.