Abstract: This invention relates to locking mechanism for a weighing scale capable of weighing flat articles at a high rate and with a high degree of accuracy. The locking mechanism of the instant invention is applicable to a vibrating tray type scale which requires a mechanism for stabilizing the base of the scale during periods when articles are being conveyed onto and off the tray of the scale. An electromagnetic locking mechanism has been conceived that provides advantageous for a vibrating tray scale. These advantages are simple construction, low cost, self compensating and zero force requirement. With a such locking mechanism, the vibrating tray scale functions more accurately and rapidly.

Abstract: A mechanism for transporting flat articles, such as envelopes, onto and across the tray of a scale. A belt is trained about a combination of rollers received within slots of the tray which in combination with clamps supported by the tray are used to transport a flat onto the weighing scale. When a flat is to be weighed, it is transported onto the tray, the rollers are withdrawn below the tray by the belt and the clamps hold the flat securely against the tray. The tray is then oscillated and the weight of the flat is determined from the harmonic period of oscillation. Upon completion of weighing, the belt is placed into contact with the flat and rotated to remove the flat from the tray.

Abstract: A locking mechanism for securing the tray of a scale during the transporting of flat articles, such as envelopes, onto and across the tray of the scale. When a flat has been placed in a position for weighing, the conveying mechanism is put into an inoperative mode and causes the locking mechanism to release the tray. After the article is weighed, the conveying mechanism is placed into the operating mode and acts upon the locking mechanism to cause it to once more secure the tray.