The present invention relates to a shift interlock device, and more particularly to a brake-transmission-shift-ignition (BTSI) interlock device and circuit integrated into a shifter.
Brake-transmission-shift-ignition (BTSI) interlock devices and circuits are known in the art, and further it is known to incorporate a toggle mechanism and preassembled switch into such devices. For example, see U.S. Pat. No. 5,759,132 to Osborn, issued Jun. 2, 1998. A known existing BTSI shifter similar to U.S. Pat. No. 5,759,132 is described in the discussion below entitled xe2x80x9cPrior Artxe2x80x9d. (See FIGS. 1-2 of the present disclosure.) This known existing BTSI shifter includes a preassembled micro switch that is soldered onto a circuit board. The subassembly is then operably positioned in and secured to the handle of a shift lever assembly of a vehicle shifter. However, this shift lever assembly is undesirably expensive, partially because of the cost of the circuit board, but also because of secondary process costs (e.g. soldering, manual placement and attachment within the handle, and electrical connections). Also, circuit boards have quality and warranty concerns because they are not well suited for the vibrations and harsh environments commonly associated with vehicle shifters (e.g. temperature and humidity variations in the passenger compartment associated with day and night, and/or temperature extremes associated with winter and summer, and/or vibrations and with shifting the shift lever and/or associated with traveling at high speeds along a bumpy road and/or when an engine idles). Accordingly, further improvement is desired in this assembly, including reducing component costs and increasing the automation and efficiency of assembly, and improving the durability and robustness of the shift lever assembly.
It is also known to use a lead frame in a brake shifter interlock having a toggle mechanism. For example, see Withey U.S. Pat. No. 5,938,562, which discloses a lead frame incorporated into a toggle interlock device. In the Withey arrangement, the lead frame incorporates conductive components forming a switch. But this switch arrangement can have quality problems, since the conductive components are subject to distortions and dimensional variations, wear, and other problems that occur during installation and use and during the wide temperature variations commonly experienced by shifters. This can lead to poor and unreliable operation of the integral switch. It is desirable to incorporate a preassembled switch into a circuit using a lead frame. However, problems still remain in terms of assembly and warranty problems associated with soldering and/or other electrical connections. Also, the problems associated with dimensional inconsistencies and part-handling common in lead frames need to be addressed, as well as the overall ability to automatically assemble the components.
Accordingly, a shifter is desired solving the aforementioned problems and having the aforementioned advantages.
The present invention includes a shifter for a vehicle having an electrical control circuit. The shifter includes a base, a shift lever pivoted to the base, and an interlock device on one of the base or the shifter that engages an abutment surface on the other. The abutment surface is configured to be selectively engaged by the interlock device to control movement of the shift lever. The interlock device includes a preassembled switch, an electromechanical device, and a lead frame having at least four conductors. The electromechanical device has an interlock member movable to an extended position for engaging the abutment surface and movable to a retracted position for operating the switch and allowing the shift lever to move. The four conductors operably interconnect the switch and the electromechanical device and define a three-prong terminal adapted for electrical connection to the vehicle control circuit for operating the electromechanical device and for signaling to the vehicle control circuit that the interlock member has been operated.
In another aspect of the present invention, a preassembled interlock device includes a housing and a toggle interlock mechanism including an extendable pin operably positioned in the housing. The pin is extendable to a position outside the housing for engaging an abutment surface. A preassembled switch, an electromechanical device, and a lead frame are attached to the housing in an arrangement where the electromechanical device operates the switch when the extendable pin is retracted. The lead frame includes at least four conductors operably interconnected to the switch, the electromechanical device, and to a terminal adapted for electrical connection to a control circuit for operating the electrical mechanical device, and for signaling to the vehicle control circuit that the extendable pin has been moved.
In still another aspect of the present invention, a method of assembly for an interlock device comprises steps of providing a housing, and positioning a lead frame in the housing. The method further includes operably positioning a toggle interlock mechanism in the housing, the interlock mechanism including an electromechanical device having a pin extendable to a position outside of the housing. The method also includes positioning a preassembled switch in the housing, including electrically connecting the switch to the lead frame. The method also includes electrically connecting the electromechanical device to the lead frame so that the electromechanical device operates the switch when the extendable pin is retracted. The method further includes separating parts of the lead frame to form at least four separate conductors that operably interconnect the switch and the electromechanical device to a terminal adapted for electrical connection to a control circuit for operating the electromechanical device, and for signaling to the control circuit that the interlock member has been extended.
In yet another aspect of the present invention, a preassembled interlock device includes a housing having a plurality of protrusions, and a toggle interlock mechanism including an extendable pin positioned in the housing but extendable to a position outside of the housing. The interlock device also includes an electromechanical device attached to the housing, a preassembled switch in the housing including a plurality of first contacts, and a lead frame having at least four conductors including a plurality of second contacts. When the electromechanical device is energized, it retracts the pin and operates the switch. The first contacts are positioned and oriented to telescopingly engage the second contacts during assembly. The second contacts each include a mechanical retainer that retains the first contacts in operable engagement with the second contacts and further they are adapted to electrically operably interconnect the electrical mechanical device to a control circuit for operating the electrical mechanical device. The lead frame further includes a plurality of location holes with retaining tines that engage the housing protrusions to non-releasably and accurately locate the lead frame in the housing.
In still another aspect of the present invention, a shifter for a vehicle having an electrical control circuit includes a base component, a shift lever component operably positioned on the base component, and an interlock device on one of the base and shift lever components. The interlock device is configured and adapted to selectively engage an abutment surface on the other of the components for interlocking the shift lever in a selected gear position. The interlock device includes a preassembled switch and a lead frame, with the preassembled switch having at least three first contacts and the lead frame having at least three second contacts engaged with the first contacts. The first contacts are positioned and oriented to telescopingly engage the three second contacts during assembly, and at least one of the first and second contacts each include a mechanical retainer for securely retaining the first contacts in operable engagement with the second contacts after assembly.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.