Abstract: An apparatus for heat staking plastic parts to other parts to form an assembly are featured, using multiple heating elements which are arranged in zones and which are separately programmable in terms of temperature and displacement to develop optimum deformation of plastic having different characteristics. The heating elements are isolated thermally to provide an improved conservation of heat energy.

Abstract: Electrical continuity between the terminals of a multi-contact electrical connector and the cores of insulated leads that have been connected thereto, is tested for by engaging a respective electrical test probe with each of the terminals and using a multiplexer to connect each test probe in turn to a continuity testing circuit, under the control of a computer. Following the continuity test, a bank of analog switches also controlled by the computer is used to apply short circuit test electrical potential to energize selected terminals, and the presence of the test potential on adjacent unenergized terminals is tested for by the computer, to detect short circuiting between the terminals.

Abstract: The ultrasonic energy applied to a workpiece to be welded in an ultrasonic welding operation, over a predetermined welding time, is measured by processing the output of a load cell beneath the workpiece to produce a signal voltage for comparison with a predetermined reference voltage corresponding to the accumulated ultrasonic energy that should have been applied to the workpiece during said predetermined time to satisfactorily weld the workpiece. A one-shot timer is started at the commencement of the welding operation. If the comparison reveals that signal voltage has reached the reference voltage before the timer has run out, a success signal is generated to indicate the completion of the welding operation.

Abstract: Electrical continuity between an electrical terminal and a metal core of an insulated electrical lead is tested for, by supplying substantially identical oscillatory signals to the arms of a two-arm bridge circuit, the arms of which are connected to respective inlets of a differential amplifier, the arms being grounded through capacitances and a ground plane existing in the vicinity of the lead. If there is electrical continuity between the terminal and said core, the capacitance between the core and the ground plane causes imbalance between the signal inputs that are applied by the bridge circuit to the differential amplifier to cause it to emit a continuity success signal.

Abstract: A platen for printers is disclosed. The platen has a tubular resilient sleeve with an outer cylindrical circumferential surface. Shaft means is contained within the sleeve. The shaft means has portions exposed at the ends of the sleeve which are concentrically aligned with the sleeve's outer surface. A molded in place core fills the space between the sleeve and shaft means to connect the two together and to prevent their relative rotation. The method of manufacturing the platen includes filling the sleeve with moldable plastic material and subjecting the plastic to a curing operation while holding the shaft portions in concentrically aligned position relative to the outer surface of the sleeve.

Abstract: An induction heating apparatus for heating an electrically conductive workpiece, comprising a C-shaped core made of a material having a high magnetic permeability and having two closely opposed tapered ends, an exciting coil surrounding the core, and a circuit for supplying a periodic voltage to the coil so as to cause a varying magnetic field to be produced in the core and to efficiently focus a field of high flux density between its two ends. In one embodiment the core is made of ferrite, a capacitance is connected with the exciting coil to form a resonant circuit, and circuitry is provided for detecting the phase of the current flowing in the resonant circuit and for controlling the frequency and phase of the periodic voltage supplied to the resonant circuit so as to maintain the circuit in resonance.

Abstract: An improved transistor, an improved lead frame for use in transistor manufacture, and manufacturing methods for transistors are disclosed. The improved transistor lead frame has a premolded housing thereon which covers a substantial portion of the chip-mounting surface of the transistor heat sink. A chip-receiving cavity is provided in the molded housing which extends to the chip-receiving surface and conforms to the shape of the chip. Solder-receiving bays or bins extend laterally from the cavity to receive excess solder during bonding of the chip to the lead frame. The premolded housing surrounds the chip after it is bonded to the lead frame and when the conductors from the transistor leads to the chip are bonded in place, the housing protects these leads during subsequent handling. The hollow interior of the housing is filled with a silicone gel which encapsulates the conductors in the housing and a harder insulating material, such as epoxy, is applied over the gel.

Abstract: A continuous strip of stamped and formed lead frames for a semi-conductor chip comprises a continuous carrier strip having three laterally extending arms integral therewith. One of the arms has a chip receiving surface to which the chip is soldered. The other arms have reversely bent end portions which extend over the chip receiving surface and which are intended to be connected to contact areas on the upwardly facing surface of the chip. Each of the arms has an integral terminal member extending therefrom in the plane of the strip and these terminal members are later bent upwardly relative to the plane of the strip so that they surround the chip receiving surface. The terminal members may comprise rectangular tabs formed by folding the stock metal of the strip and dimensioned to receive complementary contact terminals on the ends of wires thereby to connect the contact areas of the chip to external circuitry.