Ford's HN80 program was a massive redesign in the mid-1990's using a very un-trucklike, modern interior including cruise switches on the steering wheel.
At Eaton we took on the project very late. Ford had run ahead with steering wheel design and left space for a particular fast acting momentary switch. When Ford returned to Eaton with the project, the wheel was already tooled, but they required a maintained switch action for the ON OFF control of the electronic cruise module. This switch needed to look and feel like a momentary switch, but present a maintained action to the cruise control module. No such switch existed that would fit into the nearly complete wheel, and mold tooling was almost completed, thus a new design was needed very late in the product development cycle.
Other new requirements were a strong detent tactile response, and insert molded graphics so the symbols, ON, OFF, SET, & RESUME would never be worn off.
My solution was to produce an electronic switch package that closed a reed relay when the ON was pressed and release when the OFF was pressed. This Set/Reset action was provided by using a 555 timer IC to save space on the printed circuit. There is a patent for this circuit. The Set & Resume switch used a simple PCB with only dome switches to provide a tactile response similar to the ON/Off rocker.
Dome switches on a hard nickel plated printed circuit provided the strong detent feel that would be noticed with heavy gloves and durring a lot of vibration.
At Eaton we took on the project very late. Ford had run ahead with steering wheel design and left space for a particular fast acting momentary switch. When Ford returned to Eaton with the project, the wheel was already tooled, but they required a maintained switch action for the ON OFF control of the electronic cruise module. This switch needed to look and feel like a momentary switch, but present a maintained action to the cruise control module. No such switch existed that would fit into the nearly complete wheel, and mold tooling was almost completed, thus a new design was needed very late in the product development cycle.
Other new requirements were a strong detent tactile response, and insert molded graphics so the symbols, ON, OFF, SET, & RESUME would never be worn off.
My solution was to produce an electronic switch package that closed a reed relay when the ON was pressed and release when the OFF was pressed. This Set/Reset action was provided by using a 555 timer IC to save space on the printed circuit. There is a patent for this circuit. The Set & Resume switch used a simple PCB with only dome switches to provide a tactile response similar to the ON/Off rocker.
Dome switches on a hard nickel plated printed circuit provided the strong detent feel that would be noticed with heavy gloves and durring a lot of vibration.
The new switch design was life tested for a million cycles over a range of ambient conditions from below freezing to 120°F (IIRC) with condensing moisture. Eaton Selma was equipped with a UL accredited testing facility, so we were able to build the test apparatus quickly in house and finish the testing on time.
Sculpted buttons rockers carved from wood were provided as masters to work from. These were laser scanned. Modeling was in AutoDesk's AutoSurf using the scanned cloud of points. The insert molded switch buttons were produced by a rapid manufacturing house in Indianapolis called Compression Engineering. Due to a lack of time to have the molded parts reviewed the CNC'd electrodes for creating the switch molds were taken to Dearborn for review.
There was a tricky moment when the Ford styling people decided some radii on the switch rockers were too sharp. I bought some fine sand paper, and gently eased the radii until the styling people were satisfied. I then delivered the electrodes to Compression to burn the mold inserts. Getting the curved surfaces to mold well without the black flashing over the white letters was a challenge. My souvenirs in the images are early parts where they still needed to crush the white insert a bit more to make the letters bolder.
Sculpted buttons rockers carved from wood were provided as masters to work from. These were laser scanned. Modeling was in AutoDesk's AutoSurf using the scanned cloud of points. The insert molded switch buttons were produced by a rapid manufacturing house in Indianapolis called Compression Engineering. Due to a lack of time to have the molded parts reviewed the CNC'd electrodes for creating the switch molds were taken to Dearborn for review.
There was a tricky moment when the Ford styling people decided some radii on the switch rockers were too sharp. I bought some fine sand paper, and gently eased the radii until the styling people were satisfied. I then delivered the electrodes to Compression to burn the mold inserts. Getting the curved surfaces to mold well without the black flashing over the white letters was a challenge. My souvenirs in the images are early parts where they still needed to crush the white insert a bit more to make the letters bolder.