Demand meter for on-peak maximum demand metering

Claim 1

A demand meter for periodically measuring maximum watt demand during a desired on-peak demand measuring period, comprising: a watt-hour metering means responsive to the consumption of electrical energy of an electric load; a timing motor means having an output rotated at a constant rate; an on-off timing mechanism having a timing input rotatably driven in response to said output of said timing motor means, said on-off timing mechanism further including a releasable coupler means including a metering drive input and an output with said metering drive input connected to said watt-hour metering means, said coupler means being operable between coupling and decoupling states so as to connect and disconnect, respectively, said metering drive input and said output, and said on-off timing mechanism further including rotational means responsive to said timing input for rotation through a daily time cycle to effect the coupling and decoupling operation of said releasable coupler means during predetermined daily periods to establish said desired on-peak demand measuring period; a maximum demand indicating means including a pusher drive and reset mechanism and a dial pointer for indicating maximum power demand of the load, said pusher drive and reset mechanism including a pusher drive operating input and a reset operating input with said pusher drive operating input connected to said output of said releasable coupler means only when said releasable coupler means is in said coupling state during said on-peak demand measuring period; a demand interval timing means including an input driven in response to said output of said timing motor means and an output connected to said reset operating input of said pusher drive and reset mechanism, said demand interval timing means further including an intermittent motion arrangement connected between said input and output of the demand interval timing means to operate said reset operating input at predetermined demand intervals; and a time indicating mechanism including an input driven in response to said output of said timing motor so as to be driven therefrom in a common driven relationship with both said on-off timing mechanism and said demand interval timing means, said time indicating means further including a clock dial pointer and a manually adjustable time reset member, said reset member being operable to adjust the timing indicating mechanism so that said pointer is repositioned at a desired time setting and to concurrently reposition said on-off timing mechanism to maintain the same operative relationship therebetween whereby said desired on-peak demand measuring period occurs at predetermined daily periods indicated by said clock dial pointer.