Tape rule assembly with differential spring-drive systems
AssigneeStanley Black & Decker, Inc.
InventorsAntony Orsini, Keith M. Lombardi, Bruce Eidinger
Life of this patent
Estimating the term…
Abstract
A tape rule assembly includes differential spring-drive systems for rotating a reel of tape through an angular distance different from the angular distance traveled by a hub carrying a wound spring, relative to the tape rule housing. The differential spring drive systems include planetary and cycloidal drive systems. The tape rules of the present invention are thus made more compact than conventional tape rules.
Claims10
A tape rule assembly including a length of tape and a wound spring operatively associated with the tape, comprising:
- a housing defining an enclosed space;
- and
- a differential spring-drive subassembly rotatably disposed in the housing enclosed space, the differential spring-drive subassembly operative to tighten the spring around a hub when the tape is extended from the housing, wherein the differential spring-drive subassembly includes a cycloidal drive system;
- wherein the hub defines a single, self-contained spindle;
- and
- wherein the enclosed space is uninterrupted by any other spindle;
- the differential spring-drive subassembly includes a reel supporting the length of tape, the reel and the hub being rotatable about an axis of rotation relative to the housing;
- the reel is disposed in the housing concentrically about the hub;
- and
- wherein the reel and the hub are operatively associated with the housing so that, when the tape is extended from the housing, the reel rotates through a first angular distance, and the hub rotates through a second angular distance different from the first angular distance;
- the housing includes a housing member defining a gear member axis eccentric to the axis of rotation;
- and further comprising:
- a gear member rotatably disposed in the housing about the gear member axis and operatively associated with the hub and the reel;
- wherein, as tape is withdrawn from the reel, the consequent rotation of the reel about the axis of rotation results in eccentric rotation of the hub relative to the housing;
- and
- wherein the hub rotates through an angular distance different from that of the reel.
A tape rule assembly, comprising:
- a housing;
- and
- a cycloidal differential spring-drive system having an eccentric bearing to create an eccentric cycloidal motion rotatably disposed in the housing;
- wherein the cycloidal differential spring-drive system includes a reel supporting a length of tape and a hub supporting a coil of spring;
- and
- wherein the reel is operatively associated with the housing and the hub so that when tape is extended from the housing, the reel rotates through a different angular distance than does the hub.
A method of minimizing the diameter of a coil of spring disposed around a hub of a tape rule assembly having a housing, comprising:
- creating an enclosed space within the housing uninterrupted by a spindle;
- and
- rotatably disposing a cycloidal differential spring-drive system within the enclosed space, such that rotating a reel of the differential spring-drive system through a first angular distance causes the hub of the differential spring-drive system to rotate through a second angular distance different from the first angular distance;
- wherein the cycloidal differential spring-drive system has an eccentric bearing to create an eccentric cycloidal motion.
Dependencies are inferred from the claim text.