BRIEF DESCRIPTION OF THE DRAWINGS
The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is an exploded perspective view of mating blade and handle components for use in a circuit breaker having a layered construction;
FIG. 2 is an exploded perspective view of mating end portions of a modified pair of blade and handle components for use a circuit breaker having a layered construction;
FIG. 3 is an exploded perspective view of mating end portions of another modified pair of blade and handle components for use in a circuit breaker having a layered construction;
FIG. 4
a is an perspective view of adjacent portions of toggle spring and trip lever components for use in a circuit breaker having a layered construction;
FIG. 4
b is a section taken along line 4-4b in FIG. 4a; and
FIG. 4
c is a top plan view of the toggle spring and trip lever components shown in FIG. 4a; and
FIG. 4
d is a perspective view of the toggle spring component of FIGS. 4a-4c.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to include all alternatives, modifications and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims.
Referring now to the drawings, FIGS. 1 and 2 illustrate a handle 10 and blade 11 for use in a circuit breaker of the type described in U.S. Pat. Nos. 5,946,179 and 6,482,048. The blade 11 carries a movable electrical contact 12 that is moved into and out of engagement with a stationary electrical contact (not shown) when the blade is pivoted about an axis 13. Pivoting movement of the blade is effected by the handle 10 and/or a toggle spring (not shown) connected to the blade 11 to apply a biasing force to the blade.
To facilitate automated assembly, the components of a circuit breaker utilizing the handle 10 and blade 11 are typically designed with a “layered” structure, so that the various components can be assembled sequentially on the base of the circuit breaker. The components extend primarily in X and Y directions, parallel to the base of the circuit breaker, and are layered in a Z direction that is orthogonal to the X and Y directions and that determines the thickness of the circuit breaker.
The handle 10 and blade 11 are coupled in a manner that causes the blade 11 to be pivoted whenever the handle 10 is pivoted, while also permitting pivoting movement of the blade 11 relative to the handle 10. In the illustrative embodiment, the blade 11 forms an integral tab 14 extending upwardly, in the Z direction, from the main body of the blade, which lies in an X-Y plane. During assembly, the blade 11 is inserted into the circuit breaker assembly before the handle 10, and the handle is positioned so that the tab 14 fits into a generally V-shaped notch 15 in the end of the handle 10. The notch 15 allows pivoting movement of the blade 11 relative to the handle 10, while still coupling the handle to the blade 11 via the tab 14 so that the handle 10 can be used to move the blade 11. For example, when the handle 10 is pivoted in the clockwise direction, as viewed in FIG. 1, the notch surface 15a engages the tab 14 to pivot the blade 11 in the counterclockwise direction. Conversely, when the handle 10 is pivoted in the counterclockwise direction, as viewed in FIG. 1, the notch surface 15b engages the tab 14 to pivot the blade 11 in the clockwise direction.
One of the advantages of the arrangement shown in FIG. 1 is that it helps to stabilize the blade 11 when the toggle spring is attached to the blade 11, after installation of the handle 10. The fact that the axis of the toggle spring lies in a plane above that of the blade 11, and that the toggle spring is attached to the end of the blade that carries the contact 12, means that the toggle spring applies a lifting force to the contact end of the blade, tending to tilt the contact end of the blade 11 upwardly, in the Z direction, as indicated by the arrow 16 in FIG. 1. However, portion 17 of the blade body, adjacent the tab 14, extends under the portion of the handle 10 adjacent the notch surface 15a, which resists and lifting force applied to the blade by the toggle spring during assembly. Furthermore, the fulcrum for any upward tilting of the contact end of the blade 11 is where the upper corner 14a of the tab 14 engages the upper end of the notch 15, which is closer to the axis of the toggle spring and thus reduces the moment arm of any Z-direction force applied to the blade 11 by the toggle spring, thereby reducing the force that must be resisted to stabilize the blade 11 during assembly.
FIG. 2 illustrates a modified embodiment in which one side of a notch 20 in a handle 21 is shortened to reduce the friction between overlapping surfaces of the handle 21 and a blade 22. In addition, the tab 23 formed by the blade 22 includes a notch 23a that fits over a complementary rib 24 in the throat of the notch 20 to control the position of the blade 22 relative to the handle 21 in the Z direction.
FIG. 3 illustrates another modified embodiment in which a tab 30 extends beyond the tab end of the body portion of a blade 31 so that a rectangular notch 32 can be formed in the lower edge of the tab 30. This forms a depending leg 33 on the front end of the tab 30. The mating handle 34 forms a notch 35 which extends through the full thickness of the handle only in the throat of the notch, thereby forming a cross member 36 that extends across the lower portion of the mouth of the notch. When the blade 31 and handle 34 are assembled, the notch 32 in the lower edge of the tab 30 fits over the cross member 36, so that any upward tilting force subsequently applied to the blade 31 by the toggle spring is resisted by engagement of the notch surface 32a with the inboard surface 36a of the cross member 36, thereby stabilizing the blade against tilting movement in the Z direction. As in the embodiment of FIG. 2, the tab 30 includes a notch 30a that fits over a complementary rib 37 in the throat of the notch 35 to control the position of the blade 30 relative to the handle 34 in the Z direction.
The toggle spring referred to above is attached at one end to the blade that carries the movable electrical contact, and at the other end to a trip lever. FIGS. 4a-4d illustrate an improved structure for attaching the end of a toggle spring 40 to a trip lever 41. Rather than forming a hook, the end of the spring 40 is bent downwardly to form a leg 42 extending in the Z direction, and then a substantially closed circular loop 43 lying in an X-Y plane. The mating portion of the trip lever 41 forms a V-shaped notch 44 so that when the leg 42 of the spring 40 is inserted into the throat of the notch 44, portions of the loop 43 overlap portions of the lower surface of the trip lever 41 along opposite edges of the notch 44. This provides a secure connection that is easy to assemble, and avoids the problems caused by the catching of open hooks during assembly operations.
While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and operation disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
Patent Application
20080067047
