There is disclosed a process for encrypting a data stream to secure the data stream for single viewing and to protect copyrights of the data stream. Specifically, there is disclosed a process for protecting streaming multimedia, entertainment and communications in an Internet-type transmission. There is further disclosed a streaming server component operably connected with a streaming server that interacts with a client system that includes a virtual smart card to effect the inventive process.

Process and streaming server for encrypting a data stream to a virtual smart card client system

The present invention provides a weld control monitoring system (10) which determines the quality of the welds in real time, and provides responsive useful outputs indicating the quality of the weld The system (10) permits the user to input weld data as well as quality specifications which the part must meet in order to continue the production run A monitoring system can be used with or without programmable logic controllers (16) and includes special program for estimating the tip wear of the welding electrodes (34) The present invention also includes a weld gun control Additional travel for the weld gun electrode (34) is provided by cylinder (40) adjacent rail structures (50) which permit displaceable movement of the electrode mounted to linear displacement welding cylinder (30) An LVDT sensor (35) coupled to the piston rod (32) of the weld cylinder provides linearly variable displacement transducer signals for use in monitoring portion (14) of the apparatus The monitoring apparatus (14) also provides statistics of individual and groups of parts produced with the welding apparatus

Automatic welder control system

A spot welding machine includes tip electrodes (8, 9) mounted on the tips of the first and second arms (4, 5), respectively, a pressing actuator (1) for moving at least one of the first and second arms to apply a pressing force to the tip electrodes, a detector (2) for detecting a distance between the tip electrodes, and a brake (30) for braking the actuator. The distance between the tip electrodes can be set at any desired intermediate distance between the maximum and minimum distances, by braking the actuator when the arms are opened or closed to a desired degree. It is made possible to reduce the required operation time and to lessen an impact caused when the tip electrodes come into contact with plates to be welded. A speed control device may be provided which variably controls the moving speed of the actuator in accordance with the distance. A determining device may be provided, which determines the current distance meets a predetermined reference value.

Spot welding machine

Apparatus and accompanying methods for use therein for measuring and controlling weld indentation during resistance welding operations are disclosed. During a welding operation, the apparatus measures changes in a distance separating a reference point located on an electrode assembly and a region situated on the surface of the workpiece being welded wherein the region is not substantially indented by the electrode. Specifically, a distance measuring system first establishes the location of the surface relative to the electrode before any welding current is passed through the weld area. The indentation is repeatedly measured by detection of ultrasonic echoes from the surface of the material being welded. Such measurements are taken at frequent intervals during the current flow period during which the weld is being formed in order to determine on a continuous basis the indentation of the electrode into the surface. The welding power may be terminated when the measured indentation reaches the desired value. In order to obtain more precise control of the indentation, the rate at which indentation occurs can be measured and the welding power can be changed on a half cycle by half cycle basis to increase or decrease the indentation rate according to a desired indentation program.

Method and apparatus for measuring and controlling indentation in resistance welding

A decrease amount in plate thickness at a spot weld is detected at a predetermined time period when application of pressure is still maintained after termination of power supply to electrodes for spot welding. The decrease amount is correlated with the magnitude of diameter of nugget formed by spot welding, e.g., a larger diameter of nugget signifies a stronger the joint, and therefore, the quality of joint at the spot weld can be examined on the basis of the detected decrease amount. Since a value obtained by integrating plate thickness detection data of the spot weld during the predetermined time period is correlated, as the decrease amount is, with the magnitude of the diameter of a nugget, the quality of the joint may also be examined on the basis of this integrated value. There is provided, in a spot welding machine, a detector for detecting a stroke position of a cylinder for pressing electrodes or a detector for detecting a position of displacement of a tip portion of an arm interlocked with the movement of the electrodes and the distance between the electrodes, i.e., plate thickness, can be indirectly detected by the detector without adversely affecting efficiency of the spot welding work.

Method for checking a spot welded portion and spot welding machine

A method and apparatus are disclosed for detecting weld nugget growth on a workpiece during a welding operation using a resistance spot welding gun. In the preferred embodiment, a piston rod is slidably mounted in a cylinder and is connected at one end to an electrode of the gun. The opposite end of the piston rod extends rearwardly through the cylinder and is coupled to a sensor assembly for detecting the amount of movement of the piston rod created by weld nugget growth on the workpiece during the welding cycle.

Dimitros Georges Cecil

Papers

Resistance spot welding gun with weld quality detection feature