US Patent 8998218 Shopping cart bottom shelf monitor

The invention includes a pivoting floor member coupled to the bottom shelf of a shopping cart. The floor member is pivotally arranged so that it assumes a first position when nothing is placed upon it and a second position when any object having more than a predetermined weight is placed upon it. The floor member is mechanically coupled to a mechanical indicator which assumes a first indicating position when the floor member is in its first position and a second indicating position when the floor member is in its second position. The indicator may be a rod and sleeve arrangement and the rod may include indicia such as one or more colored stripes.