Also mounted upon each of the respective short shafts M^{ 6}, M^{ 7}, and keyed thereto, is a ratchet wheel M^{ 11}, M^{ 12}, and adjacent thereto and loosely mounted upon each of said shafts M^{ 6}, M^{ 7} is a pawl carrier plate M^{ 13}, M^{ 14}, each carrying a pawl indicated at M^{ 15}, M^{ 16}, which is adapted to engage the teeth of the ratchet wheels M^{ 11}, M^{ 12}, being held in engagement therewith by springs, one of which is shown at M^{ 17}, secured to said pawl carrier M^{ 13}. Suitably mounted upon the casing M, and adapted to engage the teeth of the ratchet wheels M^{ 11}, M^{ 12}, is a detent M^{ 19}, to prevent reverse movement of said ratchet wheels.
The pawl carrier plate M^{ 13} is provided with a pin M^{ 21}, and secured thereby loosely to said carrier is one end of a connecting rod M^{ 21ª}, the other end of said connecting rod being connected to one end of a longitudinally flexible coupling M^{ 22}, the other end of said coupling being secured by means of the connecting rod M^{ 23} to the power transmission lever L. The function of the flexible coupling M^{ 22} will be hereinafter referred to.
The pawl carrier M^{ 13} also carries, at its lower end, a pin N, and loosely mounted thereon is one end of a connecting rod N¹, the other end of said rod being connected to a pin N² secured to the pawl carrier M^{ 14}, whereby, when motion is imparted to pawl carrier M^{ 13} and, through the pawl M^{ 15} to the ratchet wheel M^{ 11}, motion is imparted to the pawl carrier M^{ 14}, and through its pawl M^{ 16} to the ratchet wheel M^{ 12}. From the pin N² is suspended a weight N³ to return the pawl carriers to their lowermost positions when they complete their upward travel.
The flexible coupling M^{ 22} comprises a tubular casing N^{ 4}, which is provided at one end with an opening N^{ 5}, through which projects a rod N^{ 6} having a head N^{ 7}, which is adapted to bear against a spiral spring N^{ 8} mounted within said casing, the other end of said rod N^{ 6} being connected to the rod M^{ 23}.
The operation of the apparatus, as thus far described, will be more readily apparent from an inspection of Fig. 5.
Assuming that the expansion coil there shown has been subject to a normal temperature of say 75 degrees Fahrenheit, and at that temperature the lever L is in the position shown in full lines on a decrease in temperature of say 10 degrees, the contraction of the coil, which will operate upon its entire length, will exert a pressure at the ends thereof in the direction of the arrows, the result of which will be to rotate the shaft J and raise the lever L against the force of the weighted lever K (carrying the latter therewith) to the position shown in dotted lines, thereby actuating the ratchet wheels M^{ 11}, M^{ 12}, and winding up the springs M^{ 9}, M^{ 10}, of the power-storage device, the force there stored being afterwards taken off, as required, through the medium of the power transmission shaft M¹ and spur wheel M² and any suitable gearing or power transmission means.