Geometrical instruments – Distance measuring – By flexible tape
Reexamination Certificate
1999-08-04
2001-06-12
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Distance measuring
By flexible tape
C033S755000
Reexamination Certificate
active
06243964
ABSTRACT:
BACKGROUND OF THE INVENTION
Spring retractable rule assemblies have been available commercially for many years. Among the most desirable characteristics commercial rule assemblies can possess is a relatively long total blade length and a relatively compact housing that is of a size and shape, for example, that can easily and comfortably fit in a hand of person using the assembly or that can easily be carried in a pocket or on a belt.
A typical retractable tape rule assembly includes an elongated thin metal rule blade that is mounted on a reel rotatably disposed within a housing assembly. The rule blade is retracted into the housing assembly for storage by coiling it about the reel. In a spring retractable type rule assembly, a coil spring is mounted inside the reel between the reel and a spindle of the housing assembly to provide spring powered rewinding of the blade.
A typical coil spring has a flat ribbon-like metal structure. Spring power is directly related to spring width, thickness and length so that spring power can be increased by increasing any combination of these three dimensions. Increasing spring thickness and/or length, however, requires making the height and length of the housing assembly (i.e., the side dimensions or “footprint”) larger. It is particularly important to minimize the footprint of the housing assembly if the same is to be conveniently gripped or carried. Prior art rule blade assemblies used a construction in which the spring width is significantly less than the blade width. When spring power had to be increased in prior art assemblies, spring length and/or particularly spring thickness were increased which tended to make the footprints of prior art housing assemblies relatively large and cumbersome, particularly if blade length was long.
Prior art housing assembly construction also typically used four fasteners located generally in four corners of the housing assembly to secure the housing assembly together. These fasteners were usually four axially extending bolts (where “axial” refers to the direction of the axis of rotation of the reel defined by the spindle). These four fasteners were typically disposed outside of the periphery of the reel. This positioning of the fasteners tends to increase the footprint of the housing assembly. Furthermore, the need for four corners in the housing assembly required that the housing assembly footprint be somewhat square and this square shape is relatively difficult to grasp was one hand.
There is a need for a spring-powered retractable rule assembly having a housing assembly footprint size that is as small as possible for a given blade length and having a footprint with a minimum number of corners and peripherally disposed fasteners to make the housing assembly as easy to hold in a single hand as possible.
BRIEF DESCRIPTION OF THE INVENTION
An object of the present invention is to fulfill the need expressed above. In accordance with the principles of the present invention, this objective is achieved by providing a retractable rule assembly comprising a housing assembly and a reel rotatably mounted in the housing assembly. An elongated blade formed of a ribbon of metal having one end connected to the reel is constructed and arranged with respect to the housing assembly to extend from a position tangential to the reel outwardly through a spaced opening in the housing assembly. A coil spring formed of a ribbon of metal is a constructed and arranged between the housing assembly and the reel to rotate the reel in the housing assembly in a direction to wind up the elongated blade when extending outwardly of the housing assembly opening in a normal concavo-convex cross-sectional configuration onto the reel in an abutting volute coil formation in a flattened cross-sectional configuration. A blade holding assembly is provided which is manually actuated to hold the blade in any position of extension outwardly of the housing assembly opening and to release the blade from any position in which it is held. The metal ribbon of the spring has a width that is 95 percent to 120 percent of the width of the metal ribbon of the blade. More preferably, the metal ribbon of the spring is 100 percent to 110 percent of the width of the metal ribbon of the blade.
In the more specific aspects of the present invention, it is a further object to provide a retractable rule assembly having a reduced size as previously described with the following additional features:
1. The blade has a blade width, thickness and height of concavo-convex curvature sufficient to enable the blade to stand out arcuately a length measured along the blade of approximately 11 feet with a horizontal linear length of standout thereof greater than 97% of the arcuate length of standout.
2. A retractable rule assembly wherein the elongated blade has a width in the flattened configuration thereof having a dimension within the range of 1.10″-1.5″, a height in the concavo-convex configuration thereof having a dimension within the range of 0.25″-0.40″ and a thickness in either configuration thereof having a dimension within the range of 0.0045″ to 0.0063″.
3. A retractable rule assembly wherein the concavo-convex cross-sectional configuration of the blade includes an arcuate central section having a predetermined radius of curvature and integral arcuate end sections each having the same radius of curvature, the radius of curvature of the central section being a dimension within the range of 0.35″ to 0.60″ and the radius of curvature of each end section being a dimension within the range of 1.0″ to 5.0″.
4. A retractable rule assembly wherein a relatively short free end portion of the blade has a clear film of plastic material adhered to a concave side thereof.
5. A retractable rule assembly wherein the blade has an end hook member on the free end thereof, the end hook member being formed of sheet metal of a predetermined thickness to include a concavo-convex mounting portion having a U-shaped hook portion bent at a generally right angle from an end thereof, the end hook member being mounted on the free end of the blade with the mounting portion thereof secured in limited sliding engagement with a concave side of the free end of the blade so that the rule can be measured externally from an exterior surface of the U-shaped hook portion or internally from an interior surface of the U-shaped hook portion, the U-shaped hook portion including a bight section extending transversely from a convex side of the free end of the blade and spaced leg sections extending beyond transversely spaced corners of the free end of the blade.
6. A retractable rule assembly wherein the housing assembly includes a pair of cooperating housing members, each including an end wall having a peripheral wall extending from a periphery thereof and terminating in a free edge, the housing members being fixed together with their free edges interengaged by a plurality of bolts extending through one of the housing members and threadedly engaged in the other at spaced positions adjacent the peripheral walls thereof and by a fixed reel spindle having a non-circular interengaging recess-projection connection at each end thereof with the central interior of the adjacent end wall, each end of the spindle being interiorly threaded to threadedly receive a bolt therein extending through a central hole in the adjacent end wall and the recess-projection connection between the central hole and threaded interior.
7. A retractable rule assembly wherein the housing assembly includes a fitment defining a part of the housing assembly opening adjacent a convex side of the blade, the fitment having a plurality of tangentially extending transversely spaced elongated ridges defining surfaces for engaging the convex side of the blade extending tangentially from the reel to said housing assembly opening.
8. The housing assembly includes a bottom wall having an exterior portion at an end position adjacent the housing assembly opening which projects below the exterior surfa
Bennett G. Bradley
Pillsbury & Winthrop LLP
The Stanley Works
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