公开(公告)号：US3823280A

公开(公告)日：1974-07-09

申请号：US40996173

申请日：1973-10-26

Applicant: CONTROLS CO OF AMERICA

Inventor： OBERMANN G ,  ENGER M ,  MISIK M

IPC: H01H43/10 ,  G04C23/16 ,  H01H43/02

CPC classification number: H01H43/022 ,  G04C23/16 ,  H01H43/026 ,  H01H2011/062

Abstract: The motor subassembly is mounted in the housing with the motor leads dressed between the motor case and the housing and connected to the motor terminal and to a switch blade terminal and does not require grounding. The gear case somewhat divides the motor case to retain the coil while the motor case cover cooperates with the gear case to enclose and journal the gearing with the drive pinion projecting therebetween to drive the gear on the perimeter of the timing cam. The timing cam is journaled on the bushing extruded from the motor cover and in the aperture in the housing cover with the gear cluster extension projecting into and visible in the cam hub to afford visual verification of motor operation. The three switch blades are accurately located in the housing by tabs engaging locating cavities and the pivoted yoke has pads which space the two outside blades from each other. During the time between defrost cycles the No. 1 blade rides on the cam with the No. 2 blade engaging the No. 1 blade. When the No. 1 blade drops off the cam drop, the No. 3 blade engages the No. 2 blade and remains so engaged until the No. 2 blade drops off the cam. The tangential distance between the ends of blades No. 1 and No. 2 determines the duration of the cycle in combination with the rotational speed of the cam. All components are trapped by the assembly of the cover to the housing which is accomplished without fasteners. The great reduction in parts while completely enclosing the product results in a quiet, low cost, accurate timer which is easily serviced in the field by way of easy verification of operation.