Patent GB-720425-A (GB)
Title: Improvements in and relating to defective lamp detecting and ejecting mechanism
IPC: H01J9/42
Filed: 1952-06-30
Abstract: 720,425. Making electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. June 30, 1952 [June 30, 1951], No. 16401/52. Class 39 (2) Mechanism for testing electric incandescent lamps for continuity between leading-in wires and filament while being indexed around on a carrier either before or after the attachment of a cap to the lamp, and ejecting automatically those lamps which are faulty, comprises contacting devices mounted at a testing station for reciprocation into engagement with the leading-in wires of a bulb arriving at that station and a relay system which is energized upon failure to close the bulb circuit and operates a pusher device for ejecting the bulb from the carrier. The indexing carrier may be of the type comprising an endless chain 16 connected at intervals along its length to rectangular base plates 8 carrying pairs of jaws 9, 10 secured upon cranked pivot rods 11, 12 respectively associated with springs 13, 14 tending to close the jaws. As shown. in Fig. 1, a lamp bulb 1a which has had the lateral leading-in wire 4 oriented into a predetermined position, either manually or automatically, is moving towards the testing station occupied by a bulb 1 b under test, while a satisfactory bulb 1c is shown within the chuck assembly 7c. The testing apparatus comprises a pair of contact devices 22, 23 co-operating respectively with the vertical leading-in wire 3 and lateral wire 4. Contacts 22 comprise a stationary bar 24 on a mounting insulated. from the machine frame, and a pivoted bar 25 mounted at the lower end of an insulated spindle 26 which is journaled in the machine frame and carries at its upper end a crank 27 connected to a tensioned spring 28 tending to close the bar 25 on to the fixed bar 24 and grip the vertical wire 3 therebetween. During the indexing movement of the conveyer, the pivoted contact bar 25 is swung outwardly by a short crank 29 engaging the crank 27, the crank 29 being secured at the end of a shaft 30 carried by a crank arm 31 on a long push-rod 32 which is linked at its lower end to a rocking-arm 33 controlled by a cam 35 rotated in synchronism with the conveyer movements. Contacts 23 which engage the lateral wire 4 undergo vertical reciprocation to raise them above the path of movement of the bulbs when the conveyer is indexing and subsequently to pull the wire down against the bulb neck. The contacts 23 are constituted by a pair of co-operating contact arms 40, 41 pivotally mounted at the lower ends of a pair of scissor arms 42, 43 and normally restrained in a substantially horizontal position by tensioned springs 44. The scissor arms are mounted on pivot pins 45, 46 on a primary crosshead 47 slidably mounted on a guide rod 48 that is inclined slightly forwardly to facilitate the operation of the contact arms 40, 41. A tensioned spring 49 tends to hold-the crosshead in its upper position. The crosshead is in the form of a hollow rectangle enclosing a collar 50 that is also slidable on the rod 48 and has secured to it a secondary crosshead 51 consisting of a plate provided with slanted slots 54, 55 which receive pins 52, 53, so that the contact arms 40, 41 are brought together or separated consequent upon relative motion between the primary and secondary crossheads 47 and 51 respectively. Such movement of the secondary crosshead is effected by a system comprising a crank 57 secured on the cam-controlled shaft 30 and connected by a link. 56 to the crosshead. When the conveyer system is in movement the raised portion of the cam 35 is operative to displace the secondary crosshead 51 upwards with respect to the primary crosshead 47 and also to raise both crossheads together as a unit, with the result that the lower ends of the scissor arms are opened and also raised clear of the path of the bulbs. After the conveyer has stopped with a lamp at the testing station, the contacts 22 engage the top leading-in wire 3 through the pivoting of bar 25, while the lateral wire 4 is gripped between contact arms 40, 41 and pulled downwardly due to downward movement of the primary and secondary crossheads, and assumes the form shown at 1c. In the event that a circuit is not completed through the leading-in wires and filament, an electric relay system, Fig. 3 (not shown), is operated whereby a pair of solenoids 60, 61 are energized respectively to release and eject the bulb from its holding chuck. The armature of solenoid 60 is linked to a shaft 65 carrying a pair of arms 66, 67, Fig. 2, which engage the crank arms 11 and 12 to swing the holding jaws 9 and 10 away from the bulb, and at the same time an arm 68 on shaft 65 engages a pin 69 on the push-rod 32 which is lifted in the same manner as when operated by the cam 35, so that the grip on the leading-in wires is released by their respective jaws. The armature of the second solenoid 61 is linked to a hammer crank 70 carrying an india-rubber bumper 73 which strikes the bulb from below and pushes it out of the chuck and off the conveyer. The relay system may be adjusted to respond only to a pre-determined range of current values.