Electricity: circuit makers and breakers – Combined with or actuated by connector coupling – Meeting contacts of coupling members forming switch contacts
Reexamination Certificate
1999-07-06
2001-03-27
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Combined with or actuated by connector coupling
Meeting contacts of coupling members forming switch contacts
C200S01600R, C200S051090, C200S08500R, C200S260000
Reexamination Certificate
active
06207910
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a low profile, double pole safety switch and connector assembly and, more particularly, to a double pole, plunger-type safety switch and an engaging connector assembly wherein a height of the safety switch and connector assembly along a axis defined by the path of travel of the switch actuator is minimized and further wherein the connector assembly includes a shorting member to short at least one of the two circuits upon disengagement of the connector assembly from the safety switch housing.
BACKGROUND OF THE INVENTION
Plunger switches are widely utilized in many diverse applications including use as safety switches in various motorized devices. For example, U.S. Pat. Nos. 5,424,502, issued Jul. 27, 1993 to Williams, entitled QUICK-INSTALL SEAT SWITCH and assigned to the assignee of the present invention discloses a plunger switch and quick install mounting assembly for mounting the plunger switch on a rigid seat pan of a garden or lawn tractor. The '502 patent is incorporated herein in its entirety by reference. The switch assembly disclosed in the '502 patent is a single pole plunger switch that is a switch with two terminal contacts, the plunger switch electrically coupling or decoupling the two terminals depending upon the plunger or actuator position. The mounting assembly of the '502 patent affixed the plunger switch to the seat pan such that the actuator extends above the seat pan and the switch housing was below the seat pan.
A cover overlies the actuator. When the operator is seated on the seat cushion, the cover is forced downward by the deflection of the seat cushion thereby depressing the actuator from its first undepressed position to a second depressed position. If the switch assembly was a normally closed switch (i.e., the terminals were electrically coupled with the actuator was in its first undepressed position) and the switch assembly terminals were electrically coupled between the tractor engine magneto and an electrical ground of the tractor, the tractor engine would be shut off whenever the operator stepped (or fell) off of the tractor seat. That is, actuator would return to its first undepressed position thereby closing the electrical connection between the magneto and electrical ground resulting in the magneto being grounded out and stalling the engine.
With additional switches and/or relays appropriately mounted and connected, more sophisticated safety functions could be accomplished, for example, shutting off the engine only if the operator was not sitting on the seat and the tractor's mowing blade and/or power take off was engaged. U.S. Pat. No. 5,190,019, issued Mar. 2, 1993 and entitled INTERLOCK CIRCUIT FOR DE-ACTIVATING AN ENGINE, also assigned to the assignee of the present invention discloses such a circuit. The '019 patent is incorporated in its entirety by reference. Once again, a single pole seat mounted safety switch was contemplated.
While the tractor seat pan mounted plunger-type safety switch disclosed in the '502 patent provided a securely mounted switch that was easy to mount, such a switch (and other such prior art seat mounted safety switches) provided only a single circuit (one pole) switch. With the desire for additional operational fail-safe safety functions on lawn and garden tractors and riding lawn mowers such as turning the engine off if the cutting blade is engaged and the tractor is shifted into reverse, there is a need for a safety switch having more than one pole, thereby avoiding the necessity of duplicate switches and/or relays. Further, because of limited mounting room below the seat pan, it is desirable that the switch housing and connector be configured to minimize the height of the assembly extending below the seat pan, that is, along an axis of movement of the actuator. Additionally, it is desirable to prevent an operator from bypassing the operation of the safety functions provided by a seat mounted safety switch by simply disengaging the connector coupled to the switch housing.
SUMMARY OF THE INVENTION
The present invention concerns a low profile, two pole, safety switch and connector assembly. The assembly includes a plunger type switch assembly and a connector assembly. The switch assembly includes a switch housing defining an opening through which a plunger or actuator extends and an interior region supporting switch components. The actuator is moveable along a path of travel between two positions, one position of the actuator corresponding to an undepressed position and a second position of the actuator corresponding to a fully depressed position. First and second spaced apart V-shaped contacts are mounted on a support or boss extending from the actuator and move with the actuator. Positioned along a path of travel of the first contact are first and second terminals. In one of the two actuator positions, the first and second terminals are bridged by the first contact and in the other of the two actuator positions, the first and second terminals are not bridged by the first contact. Positioned along a path of travel of the second contact are third and fourth terminals, in one of the two actuator positions, the third and fourth terminals are bridged by the second contact and in the other of the two actuator positions, the third and fourth terminals are not bridged by the second contact.
The terminals include extending portions that extend through spaced apart openings in a side wall of the switch housing thereby minimizing the effective vertical height of the switch assembly. The terminal extending portions are substantially perpendicular to the path of travel of the actuator and are sized to receive female terminals or sockets supported by the connector assembly. The connector assembly includes four female terminals that are sized and aligned to snugly receive respective different ones of the four terminal extending portions when the connector engages the plunger housing extension.
Extending arms of a flexible, electrically conductive shorting member contact a center two of the female terminals. When the connector is engaged with the plunger housing a pair of beveled, triangular shaped nubs extending from a bottom cover of the housing contacts the shorting member arms and deflects them away from contact with the female terminals. When the connector housing is not engaged with the switch housing, the shorting member arms contact the center two female terminals and the shorting member create a closed circuit condition in a circuit that the female terminals are electrically coupled to. This prevents bypassing the function of the safety switch by simply disconnecting the connector housing from the switch housing, e.g., an operator being able to start or run the tractor without sitting in the seat by simply disconnecting the connector housing from the switch housing.
These and other objects, features and advantages of the invention will become better understood from the detailed description of the preferred embodiments of the invention which are described in conjunction with the accompanying drawings.
REFERENCES:
patent: 4795865 (1989-01-01), Howard
patent: 4812604 (1989-03-01), Howard
patent: 4885438 (1989-12-01), Tajima
patent: 4894019 (1990-01-01), Howard
patent: 5190019 (1993-03-01), Williams
patent: 5424502 (1995-06-01), Williams
patent: 5613598 (1997-03-01), Pittman et al.
patent: 5775482 (1998-07-01), Wolfe et al.
Six pages from a 1999 catalog published by Delta Systems, Inc. of Streetsboro, Ohio showing and describing specifications of Delta Systems, Inc. plunger switches identified as part Nos. 6400, 6440 and 6700. to best of Applicants' knowledge, the plunger switches identified as part Nos. 6400, 6400 and 6700 were on sale more than one year prior to the filing date of the present application.
Three pages of drawings dated Jun. 10, 1999, Jun. 5, 1992 and Jun. 8, 1992, showing plunger switches identified as part Nos. 6400, 6440 and 6700 of Delta Systems, Inc. of Streetsboro, Ohio. To best of Applicants&ap
Albrecht Mark R.
Harvey Arthur James
Liedtke Michael Eric
Michaud Jan L.
Delta Systems, Inc.
Friedhofer Michael
Watts, Hoffmann, Fisher & Heinke Co. L.P.A.
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