Abstract: A chalk reel includes a housing defining a chalk chamber and an opening from the chalk chamber; a spool positioned within the chalk chamber; and a line wound on the spool and extending through the opening, the line having a width of dimension X. The spool comprises an axial hub and a sidewall. The sidewall comprises a plurality of apertures extending through the sidewall from a first face distal from the axial hub to a second face proximal to the axial hub. Each of the plurality of apertures having a maximum width of dimension Y. The dimension Y is sized so that no loops of the line may fit through each of the plurality of apertures.

Abstract: A chalk reel includes a housing defining a chalk chamber and an opening from the chalk chamber; a spool positioned within the chalk chamber; and a line wound on the spool and extending through the opening, the line having a width of dimension X. The spool comprises an axial hub and a sidewall. The sidewall comprises a plurality of apertures extending through the sidewall from a first face distal from the axial hub to a second face proximal to the axial hub. Each of the plurality of apertures having a maximum width of dimension Y. The dimension Y is less than or approximately equal to twice the dimension X.

Abstract: A chalk reel includes a housing defining a chalk chamber and an opening from the chalk chamber; a spool positioned within the chalk chamber; and a line wound on the spool and extending through the opening, the line having a width of dimension X. The spool comprises an axial hub and a sidewall. The sidewall comprises a plurality of apertures extending through the sidewall from a first face distal from the axial hub to a second face proximal to the axial hub. Each of the plurality of apertures having a maximum width of dimension Y. The dimension Y is less than or approximately equal to twice the dimension X.

Abstract: A tape rule assembly includes a linear optical encoder for sensing human-readable graduations of length disposed on a surface of a tape, without requiring any other machine-readable indicia to be present on the tape. The optical encoder includes two optical sensors disposed in a sensor holder pivotably disposed in the tape rule housing and configured to be displaced relative to one another in the housing along both the “x” axis and the “z” axis, a set of intersecting “x”, “y” and “z” axes being defined relative to a tape exit in the tape rule housing.

Abstract: A tape rule assembly includes a linear optical encoder for sensing human-readable graduations of length disposed on a surface of a tape, without requiring any other machine-readable indicia to be present on the tape. The optical encoder includes two optical sensors disposed in a sensor holder pivotably disposed in the tape rule housing and configured to be displaced relative to one another in the housing along both the “x” axis and the “z” axis, a set of intersecting “x”, “y” and “z” axes being defined relative to a tape exit in the tape rule housing.