| 摘要 |
<p>A toy balancing scale used to teach children the proper relationship between the number of objects and/or the value of numbers, has a base having an upstanding support and pivoted on the support is a horizontal balance bar. The balance bar is pivoted utilizing a fulcrum and a knife edge resting on the fulcrum. The balance bar is symmetrical about the knife's edge and as such by itself will remain in a horizontal position under the influence of gravity. At each end of the balance bar is a small peg on which objects can be attached. On the backside of the balance bar is a housing having essentially a "spade-like" shape. The distance within the housing from the top of the spade to the bottom of the stem of the spade is longer than the distance from the top of the spade to the side projections. Mounted on the support is a sliding member having a peg which projects normal to the surface of the sliding member. The member slides vertically in the support and the peg fits in the spade-like housing. When the peg is at the top of the housing the balance bar is held in a locked position about the peg. As the sliding member is moved down and if the balance bar is in balance, the peg will go straight down into the stem of the housing. If the arm is not in balance when the peg is moved from the top of the housing the arm will tilt and the peg will come to rest within the left or right side projection of the spadelike housing. Since the housing has a longer dimension from the point of the housing to the bottom of the stem than from the point of the housing to one of the side projections, the peg and the sliding member will consequently travel a greater distance when the arm is in balance than when it is not. A clanger and bell mechanism is activated by the sliding member when the member is free to travel this greater distance. If, however, i.e., the balance arm is unbalanced, the member will only be free to travel a limited amount and the clanger and bell mechanism will not be activated. This allows a child to determine whether or not the number of objects or the numbers on one side of the balance bar are equal to the number on the other side of the balance bar.</p> |
