Patent GB-1183108-A (GB)
Title: Maximum Demand Indicating Meter Reset Mechanism
IPC: G06M1/14
Filed: 1967-12-28
Abstract: 1,183,108. Maximum demand meters. GENERAL ELECTRIC CO. 28 Dec., 1967 [24 Feb., 1967], No. 58899/67. Heading G4D. [Also in Division G1] A maximum demand meter has shafts 61, 63, 65 interconnected by a gear train 67, a first drive means 5 coupled to the shafts to drive the shafts from their zero positions, a mechanism for resetting the shafts to their zero positions comprising a plate 93 for decoupling the drive means 5 from the shafts, a second drive means 135 for driving the shafts towards their zero positions and including coupling means 139 for coupling the second drive means to the gear train, and manually operable means 125, 127 operatively engaging the plate 93 and the second drive means, the manually operable means being movable to a reset position whereby the second drive means is coupled to the gear train to drive the shafts to their zero positions. The maximum demand is displayed on hundreds, tens and units dials 25, the pointers of which are attached to the shafts 61, 63, 65. The drive to these shafts from a rotating meter disc (not shown) is via the means 5 which comprises a gear train 42, crown gears 47-49 and gears 55, 81, 83. Rotation of the gears 55, 81, 83 is transmitted to crank bars 53, 77, 79 via shafts 56, 78, 80 and causes rotation of pins 57, 73, 75. Each pin engages a slot in a disc 59, 69, 71 and the rotation of the shaft 56 therefore rotates the pointer on the units dial, the rotation of the pointers on the hundreds and tens dials being effected by the gear train 67. After, for example, fifteen minutes an arm 109 of a timing mechanism 97 lifts a plate 103 via a spring 111. A tab on the plate 103 pushes an arm 115 on the plate upwardly thereby pivoting the plate 93 backwardly and disengaging the pins 57, 73, 75 from the slotted discs 59, 69, 71 as well as the gears 55, 81, 83 from the crown gears 47-49. Magnets 119 attached to a bar 107 become aligned with magnets 113 attached to each shaft 56, 78, 80 to cause rotation of the pins back to their zero positions. At the end of the reset interval the arm 109 is released and the plate 93 moves back towards its initial position but the longer pin 75 engages the flat surface of the disc 71 to prevent the plate reaching its normal position. The gears 47-49 and 55, 81, 83 remesh and unless the demand in the following fifteen minute period exceeds the previous maximum demand the pins 73, 75 do not enter the slots in the discs 69, 71 so that the driving pin 57 does not alter the maximum demand indication. A brake 120 prevents backward movement of the indication during the reset operation, a brake operating pin 128 being controlled by the plate 93. At the end of each month, for example, the maximum demand indication is reset to zero and the pins returned to their zero positions by rotating a lever 125, fixed to a shaft 127, in an anticlockwise direction. A dog 129 on the shaft 127 shifts a slide bar 133 sideways, causing a spring 135 to operate a pawl and ratchet mechanism 139 which couples the spring to the gear train 67 thus driving the indication to zero. The brake 120 is simultaneously released by the slide bar. Also, a cam 164 on the shaft 127 moves the plate 93 to decouple the pins which are magnetically attracted to their zero positions. A stop bar (183), Fig. 6 (not shown), is provided to arrest the pointers in their zero positions. Clockwise rotation of the lever 125 moves the slide bar 133 back to re-engage the brake 120. Provided the pins are in their zero positions the brake will not be in a locking position and the demand indication recommences. Overload of the demand indication is prevented by a projection on the disc 71 so that when the hundreds dial pointer moves above position eight, for example, the bar (183) is lifted by the projection to release a spring loaded brake pin 171 which pushes the plate 93 backwards to decouple the pins 57, 73, 75 and causes the brake 120 to lock the shaft 61.