Tape Rule Assembly with Differential Spring-Drive Systems

• US 20180334354A1
• Filed: 05/18/2017
• Published: 11/22/2018
• Est. Priority Date: 05/18/2017
• Status: Active Grant

• Current Assignee: Stanley Black & Decker, Inc.
• Original Assignee: Stanley Black & Decker, Inc.
• Inventors: Orsini, Antony, Lombardi, Keith M., Eidinger, Bruce
• Granted Patent: US 10,870,555 B2
• Time in Patent Office: Days
• CPC Class Codes: B65H 2403/481 Planetary
• CPC Class Codes: B65H 75/486 Arrangements or adaptations of the spring motor
• CPC Class Codes: G01B 2003/1023 Winding mechanisms
• CPC Class Codes: G01B 2003/103 operated by springs
• CPC Class Codes: G01B 2003/1053 Tape exit slots, e.g. shape or exit direction
• CPC Class Codes: G01B 3/1005 Means for controlling winding or unwinding of tapes
• CPC Class Codes: G01B 3/1041 characterised by casings

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.

Claims

1. 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 hub defines a single, self-contained spindle; and

wherein the enclosed space is uninterrupted by any other spindle.

2. The tape rule assembly claimed in claim 1, wherein:

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.

3. The tape rule assembly claimed in claim 2, wherein:

the hub includes two annular side walls defining respective bearing surfaces; and

wherein a surface of the reel is rotatably journaled on the hub bearing surfaces.

4. The tape rule assembly claimed in claim 2, wherein the differential spring-drive subassembly includes a planetary drive system.

5. The tape rule assembly claimed in claim 4, wherein:

the housing includes a tape exit and two opposing side walls; and

further comprising;

a sun gear fixedly connected to at least one of the opposing side walls and operatively associated with the reel and the hub;

wherein the reel includes an internal ring gear; and

further comprising;

at least one planet gear rotatably supported on the hub; and

wherein the internal ring gear and the at least one planet gear are aligned with the sun gear such that when the tape is extended from the tape exit, the consequent rotation of the reel causes the hub to rotate relative to the housing.

6. The tape rule assembly claimed in claim 5, wherein:

the sun gear is integrally formed on an interior surface of each opposing side wall;

the sun gears are axially aligned;

the reel has two axial ends and defines an internal ring gear proximate each axial end;

the hub includes two annular side walls; and

wherein three planet gears are rotatably supported circumferentially equidistantly on each hub side wall, and are operatively engaged with respective internal ring gears and the sun gears.

7. The tape rule assembly claimed in claim 6, wherein the reel rotates through a greater angular distance than does the hub, and in the same circumferential direction as does the hub.

8. The tape rule assembly claimed in claim 6, wherein:

the reel and hub are formed of plastic;

the hub annular side walls defining respective bearing surfaces; and

wherein a surface of the reel is rotatably journaled directly on the hub bearing surfaces.

9. The tape rule assembly claimed in claim 6, wherein the internal ring gears, the planet gears, and the sun gears are configured and aligned so that when the reel rotates through four revolutions, the hub rotates through three revolutions, thereby causing three wraps of spring to be tightened around the hub for the four revolutions of the reel.

10. The tape rule assembly claimed in claim 4, wherein:

the reel includes a sun gear axially aligned with the axis of rotation;

the hub is rotatably disposed within the reel about the axis of rotation;

at least one planet gear is rotatably supported on the hub; and

further comprising;

a cylindrical member including an internal ring gear and axially aligned with the axis of rotation;

wherein the cylindrical member is concentrically disposed between the hub and the reel and is fixed relative to the housing; and

wherein the sun gear, the at least one planet gear, and the internal ring gear are aligned with one another such that when the tape is extended from the housing, the consequent rotation of the reel causes the hub to rotate relative to the housing.

11. The tape rule assembly claimed in claim 10, wherein:

the cylindrical member includes an open end and a closed end;

the open end of the cylindrical member defines the internal ring gear;

the hub includes a side wall, and a spindle rotatably journaled about the axis of rotation in the cylindrical member closed end, in the sun gear, and in the housing; and

wherein three planet gears are rotatably supported circumferentially equidistantly upon the hub and are operatively engaged with the internal ring gear and the sun gear.

12. The tape rule assembly claimed in claim 11, wherein the hub is fixed relative to the housing, and the cylindrical member is rotatable relative to the housing about the axis of rotation.

13. The tape rule assembly claimed in claim 2, wherein the differential spring-drive subassembly includes a cycloidal drive system.

14. The tape rule assembly claimed in claim 13, wherein:

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.

15. The tape rule assembly claimed in claim 14, wherein:

the housing includes two opposing side walls;

each housing side wall defines an annular support member extending axially inwardly;

the annular support members are axially aligned along the gear member axis;

the hub is concentrically rotatably disposed within the reel about the axis of rotation and includes two side walls, each hub side wall supporting a plurality of annular members extending axially outwardly from respective hub side walls;

the axis of rotation is parallel and eccentric to the gear member axis;

the reel includes two end faces, each reel end face includes a ring defining a plurality of radially-inwardly-directed alternating cycloidal drive teeth and drive recesses;

the gear member defines a central through-bore and is disposed within, and radially aligned with, each reel end face, each gear member rotatably supported on each housing side wall annular support member via respective gear member central through-bores, such that the axes of rotation of the gear members are eccentric relative to the axis of rotation of the hub and reel;

each gear member includes a plurality of radially-outwardly-extending driven teeth, each gear member further defining a plurality of clearance apertures operatively associated with the plurality of hub annular members;

the plurality of driven teeth of each gear member is configured to cooperate with the plurality of alternating cycloidal drive teeth and drive recesses;

the number of the plurality of alternating cycloidal drive teeth and drive recesses of the reel is greater than the number of the plurality of driven teeth of the gear member;

the reel ring is configured to cooperate with the gear member, the housing and the hub so that when the tape is extended from the housing tape exit, the reel cycloidal drive teeth rotatably drive the gear member driven teeth, and the gear member in turn eccentrically rotates the hub via engagement of respective gear member clearance apertures with the hub annular members so that the angular distance traveled by the hub is greater than the angular distance traveled by the reel; and

wherein the gear member clearance apertures are configured to accommodate the eccentric rotation of respective hub annular members relative to the gear member.

16. The tape rule assembly claimed in claim 15, wherein:

the hub rotates through a greater angular distance than does the reel;

a hub outer surface includes at least one bearing surface; and

wherein an inner surface of the reel is rotatably journaled on the at least one bearing surface.

17. The tape rule assembly claimed in claim 15, wherein:

each hub annular member includes a roller engageable with the gear member via a respective clearance aperture;

each gear member includes eight equally-circumferentially-spaced driven teeth;

each reel end face defines nine equally-circumferentially-spaced sets of alternating cycloidal drive teeth and recesses; and

wherein, for every eight revolutions of the reel, the hub makes nine revolutions, thereby resulting in one wrap of spring being tightened around the hub for each eight revolutions of the reel.

18. The tape rule assembly claimed in claim 15, wherein the reel rotates in the same circumferential direction as the hub.

19. A tape rule assembly, comprising:

a housing; and

a cycloidal differential spring-drive system 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.

20. 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 one of a planetary differential spring-drive system and a cycloidal differential spring-drive system within the enclosed space, such that rotating a reel of a respective differential spring-drive system through a first angular distance causes the hub of the respective differential spring-drive system to rotate through a second angular distance different from the first angular distance.