| 摘要 |
<p>1,175,152. Thermal switches. ROBERTSHAW CONTROLS CO. 6 March, 1967 [7 March, 1966 (5)], No. 10511/67. Heading H1N. [Also in Divisions F4 and G1] A thermal switch controlling the heat cleaning operation of an electric cooker in response to a rod and tube temperature sensitive element comprises a snap action switch assembly, Fig. 3, which is allowed to open when the end member 27 of the rod moves to the left as the temperature rises. The contacts 42, Fig. 6, of the switch are carried by a forked member 32 pivoting about lugs 38 engaging slots in the switch casing. A lever member 48 is pivoted to the switch casing by lugs 50, and its free end is connected to the contact member 32 by springs 55. The operating temperature can be adjusted by a screw 53. Leaf spring switches 29, 30 are normally held closed by plungers 61, 62 engaging lever 48, but are released when the snap action switch opens. The fixed contacts of switches 29, 30 are adjustable. The cooling operations are controlled by a second rod and tube element operating a snap action switch similar to that just described through a fluid pressure transmission, Fig. 5, comprising a bellows 82 and a chamber 112 having a flexible wall carrying a stud 113 operating the switch. The operating temperature of the switch is adjusted by a knob 103 moving the chamber 112 and stud 113 towards or away from the switch. The spindle of knob 103 carries a cam actuating limit switches through toggles 133, 137. A flexible capsule 91 is arranged to compensate for ambient temperature variations. A single rod and tube element may be arranged to actuate switches in the cooking, heat cleaning and warming circuits of the oven. The end member 211 of the rod, Fig. 10, of the temperature senser operates a switch 234 through a fluid pressure transmission as described in connection with Fig. 5. A knob 114 sets the operating temperature for switch 234 and operates switch toggles 144, 148. A snap action switch 212 similar to that shown in Figs. 3 and 6 is operated by an adjustable pin 222 at the lower end of a lever 215 pivoted to the end part 211 of the temperature senser rod. The upper end of lever 215 carries an insulating block 221 arranged to allow leaf spring switches 213, 214 to open when the temperature rises. In another embodiment, the setting of a thermal switch is controlled from a remote knob by fluid pressure transmission, the movable end of the temperature senser rod carrying a fluid chamber with a flexible wall to which the switch actuating stud is secured. In this embodiment additional switches are operated by a lever pivoted to the cooker frame and secured at one end to the end of the temperature senser rod.</p> |
