Abstract: A primary electrochemical cell including a hold-down unit for securing and preventing movement of a physically large battery stack of the cell. The battery stack is disposed within a rectangular metal housing of the cell, together with an electrolytic solution, and comprises a large number of rectangular anodes and cathode structures arranged in the battery stack in alternation.The hold-down unit is disposed in the cell in abutment with the top of the battery stack and an inner surface of a cover assembly secured to the housing. The hold-down unit includes a pair of opposed end sections in abutment with the interior surfaces of one pair of walls of the housing and lying orthogonally to the planes of the components of the battery stack, and a pair of opposed connecting sections in abutment with the interior surfaces of the other pair of walls of the housing and interconnecting the pair of end sections.

Abstract: The motion of a caged laboratory animal is recorded by providing in the floor of the cage a platform which tilts slightly into one of four quadrants in response to the location of the animal within the cage. The tilting of the platform activates a switch for each quadrant, the output of the switches being recorded as a function of time. The platform has a fulcrum cone located at the center of gravity and is mounted over a platform support. The platform support includes a central pivot point over which the fulcrum cone of the platform is mounted and four upstanding posts which are located at the midpoints of the sides of the platform support. The elevation of the posts at the sides is slightly lower than the lower surface of the platform when it is balanced about the central pivot point. The switches are located at the corners of the platform support.