| 摘要 |
1406855 Making variable resistors SPECTROL ELECTRONICS CORP 3 Oct 1972 [28 Jan 1972] 45500/72 Heading HIS The lead screw member 12 in a trimmer potentiometer 11 similar to that disclosed in Specification 1,335,176, is inserted into its position using ultrasonic vibrations to instantaneously liquefy the associated housing member, which is formed with front and rear thermoplastic end walls 20 and 21 spaced apart by a side wall 22. A cylindrical aperture 23 is formed in the front end wall 20. An adjustment member such as a lead screw 12, having annular ribs 33 on its head 30, is inserted from the exterior of the housing member through the cylindrical aperture in the front wall 20. The assembly 1 is secured in housing fixture 40. The lead screw 12 is accurately aligned with groove 36 by means of fixture 50 secured in pins 44, 45 in fixture walls 42, 41. The lead screw is then ultrasonically vibrated and forced further into the housing 11 by vibratable tool 60 until its conical tip 32 penetrates rear end wall 21, to form a rear journal. Simultaneously, the ribs 33 on the head 30 of the lead screw penetrate further into cylindrical aperture 23 in the front wall 20 to form a front journal accurately aligned with the rear journal. Fixture 50 is removed and wiper 14, and substrate 13 are assembled. A second ultrasonic tool (65) (Fig. 4, not shown) engages with and deforms the side walls at locations 68, temporarily securing the substrate member 13 to the housing member 11, which is then removed from fixture 40 and sealed by a layer of potting agent such as epoxy resin 15. The invention may be applied to trimmer potentiometers with a worm gear mechanism. |
