GB1491311A - Rotary drive anti-backlash device - Google Patents

Abstract

1491311 Toothed gearing VEEDER INDUSTRIES Inc 10 Jan 1975 [11 Jan 1974] 1115/75 Heading F2Q In a gear train 34, an anti-back-lash device 60 comprises a drum 62, secured to a shaft 40 by a pin 69, and a helical coil spring 64 encircling the drum and having a first section 81 in frictional engagement with the drum and a second section out of contact with a reduced portion 72 of the drum 64 and forming a torsion spring section 82 which becomes loaded when drive is transmitted through the gear train 34. The spring 64 has a free end 74 and an end 76 which engages a fixed post 80. On the commencement of drive, in the anti-clockwise direction as seen in Fig. 2, the torsion spring section becomes loaded, the drive being transmitted through the frictional engagement of the spring section 81 with the drum. After an angular displacement of about 90 degrees the spring drive slips. When the transmission of drive ceases, the spring 64 turns the drive train in the reverse direction to eliminate back-lash. In a modification, shown in Fig. 4, drum 91 is rotatably mounted on shaft 40 and is prevented from rotating by an arm engaging a fixed post 80. In a modification, shown in Fig. 4, drum 91 is rotatably mounted on shaft 40 and is prevented from rotating by an arm engaging a fixed post 80. One end of the spring engages an aperture 95 in a member 96 secured to shaft 40. On rotation of drive shaft 40, the spring becomes torsionally loaded and rotates with the shaft 40, the friction portion slipping on the drum 91. The mechanism is applied to a fuel delivery pump.