Carrier Boat With Holes for Pins With Double Shanks
Original Publication Date: 2001-Dec-25
Included in the Prior Art Database: 2003-Jun-20
Disclosed is a carrier boat design used for fast loading and orienting large quantities of pins, each having a shank of the same diameter and wherein the shank is divided by an enlarged shoulder into two shank portions of different lengths (see Figure 1). Figure 2 is a detailed view of a standard prior art carrier boat, with examples of different pin shapes that can be loaded into the boat. To load pins, the carrier boat is placed into vibrating equipment (not shown), and vacuum is applied from underneath the boat. A sufficient quantity of pins is randomly placed over the boat, and the pins get inserted in the shank holes of the boat by action of vibration and vacuum. Figure 3 represents the type of problems occurring when a prior art boat as shown in Figure 2 is used to load pins having two shank portions of different lengths, similar to the pin of Figure 1. After loading, a random mix of pins having long and short shank portions in the shank holes of the boat results. Bent pins can also result. The new carrier boat hole design is shown in figure 4. It is used for loading and for precisely locating pins or terminals, using the loading method described above. At the completion of the loading operation, all pins are positioned with their long shank down in the holes of the boat, as at (1) in Figure 4. Each hole of the new carrier boat includes a pin shank hole, and a counter bore (2), of a diameter larger than that of the pin shank hole. The counter bore depth must be approximately the same as the length of the short shank portion of the pin. If a pin is inserted with the short shank first (3), pin will not be retained by vacuum, because the shank of short length will not penetrate into the shank hole. The counter bore diameter allows the shank of short length to be moved horizontally in the counter bore hole and to have a free roll over movement when agitated by the vibration and the loader rocking movement (4). When the longest shank of the pin is falling in place in the through hole, the vacuum retains that pin in place (1). A small countersink may be machined at the end of the counter bore depth to facilitate the long shank to be loaded in the through hole. A minimum clearance is kept between pin shank and through hole dimension. A clearance of .001 inches is preferred. This boat design can be made of any material and is in accordance with the part to which the pins will be joined, usually by soldering or brazing material, and reflow of the part and boat in a furnace. As appropriate, pins arranged in the boat may be pressed in place in the part. If there is a need to have the longer shanks of the pins oriented upwards, the pins may be loaded with long shank down and a flip flop boat used to invert the pin orientation.