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US 4,802,541 AGranted
Weighing scale with voice coil
AssigneePitney Bowes Inc.
InventorsFeliks Bator, Kevin D. Hunter, Robert T. Durst, Jr.
Life of this patent
Estimating the term…
Abstract
A weighing scale capable of weighing articles in a rapid and accurate fashion. The tray of the scale is supported by at least one spring and becomes vertically displaced in proportion to the weight of an article placed thereon. A voice coil is used to bias the tray to its original position, and the weight of the article is determined by measuring the current in the voice coil.
Claims9
A weighing scale of the force balance transducer type for weighing articles, the combination comprising:
- a housing,
- a tray,
- support means secured to said tray and received within said housing,
- at least one spring attached at one location to said support means and at another location to said housing, wherein said tray is operative to move vertically,
- said tray having a rest position when supported solely by said at least one spring without any article on said tray,
- sensing means for sensing the position and velocity of movement of said tray in response to an article being placed upon said tray,
- a voice coil attached to said support means and to said housing,
- means for providing a current to said voice coil in response to said location sensor sensing when said tray is moved downwardly from said rest position and to return said tray to its rest position after an article to be weighed has been placed on said tray,
- means for measuring the current in said voice coil,
- means for controlling the current to said voice coil in response to the position and velocity of said tray so as to expedite the return of said tray to its rest position, and
- means for determining the weight of an article on said tray in response to the measured current required to hold said tray at its rest position after an article has been placed thereon.
8 more elements
A weighting scale of the force balance transducer type for weighing articles, the combination comprising:
- a housing,
- tray having a rest position,
- a shaft secured to the tray and received within said housing,
- spring means attached at one location to said shaft and at another location to said housing, whereby said tray is operative to move vertically,
- means for determining the position and velocity of movement of said tray, said rest position being the position assumed by said tray when supported by said spring means without an article thereon,
- a voice coil attached to said shaft and to said housing,
- means for providing a current to said voice coil,
- adaptive position compensator means in communication with said and velocity determining means and with said current providing means for controlling the amount of current supplied by said current providing means in response to the position and velocity of said tray,
- means for measuring the current provided to said voice coil, and
- means for determining the weight of an article upon said tray based upon the current supplied to said voice coil,
- whereby upon an article being placed upon said tray, said tray will deviate from said rest position whereupon the amount and velocity of said deviation will be monitored by said position and velocity determining means, said current providing means in response to said position and velocity determining means will provide sufficient current to said voice coil to restore said tray to said rest position and said weight determining means determines the weight of the article on said tray in response to the amount of current required to maintain said tray in said rest position after an article has been placed thereon.
8 more elements
Dependencies are inferred from the claim text.