Патент USA US2406443код для вставки
Aug. 27, 1946. F. w. STEIN 2,406,443 ‘ 'THERMOSTATIC SWITCH ‘Filed Jan. 1, 1944 wyg ' M ' g. . ATTOK/VEK Patented Aug. 27, 1946 2,405,443 UNITED STATES PATENT OFFICE 2,406,44§ THERMosTATIc swrror'f Frederick W. Stein, Atchiso?; Kans'. Application January 1, 1944, Serial No. 516,628 1 Claim‘. ( Cl. 200L140"; 1 . The invention relates to new and useful im provements in thermostatic switches. I when the space is heated to the selected tempera ture and cl'osesthe switch when the temperature _ Speci?cally, the thermostatic switch is particu larly adapted for use in grain germinators or in other capacities where it is necessary to have a 5 readily adjustable temperature control means capable or automatically and accurately vmain drops below the selected temperature. The in vention resides primarily in the structure for op eratingrthenswitch from the wafer and in the manner in which the wafer is mounted and ad justed to operate the switch at a selected tempera ture. temperature range. For example, seed germina ’ _In the embodiment of the device shown in the tors are most e?icient if maintained at a ‘lower 10 drawing’, the switch 7 is operated by the wafer taining a selected temperature in a relatively wide temperature during the nighttime than during the daytime. Moreover, the different speci?c through the medium“ of a slidable pin. The Wafer, temperatures maintained, as well as the particu manually movable to adjust the wafer relative to the pin. The arrangement is essentially sim lar range between the daytime and nighttime temperatures, vary considerably according to the particular type of seed being germinated. An important object of the invention is to prom Vide a thermostatic switch that is automatically operative, to maintain different predetermined temperatures and that can be readily adjusted to provide a selected temperature, Another object of the invention is to provide a' device of the above mentioned character that is operative over a wide temperature range.’ Still another object of the invention is the pro vision of a device of the above mentioned char actor that is simple in construction and eilicient in operation. Other objects and advantages of the invention will be apparent during the course of the follow ing description. _ h In the drawing forming a part of this speci? cation and wherein like numerals are employed to designate like parts throughout the same, Fig. l is a top plan view of a thermostatic switch embodying the invention, Fig. 2 is a transverse sectional view taken on the line 2—2 of Fig. 1, Fig. 3 is a view similar to Fig. 1 but showing the cover of the switch housing removed, Fig. 4 is a fragmentary longitudinal sectional view taken on the line 4-—4 of Fig. 3, , itself, is mountedin a shiftable carriage which‘ is ‘ ple, making the device economical to manufac ture. At the same time, it permits precise ad justment of the wafer so that the temperature control is exceedingly accurate. Referring now to‘ the drawing, wherein for the . purpose of illustration is shown a preferred em bodiment or the invention, the numeral IIJ desig nates a‘ box or housing which consists of a base plate ma ands cover'or case “lb. The housing carries the various parts and adjuncts 0f the switch‘ and is mounted on a wall ll of the struc ture‘ to be" heated by means of end ?anges Illc. When the device" is used on a grain germinator, the housing is preferably mounted on the front wall‘ above‘ the'seed trays. Within the housing II) is a‘thermostatic'ally operated switch which com prises a switch arm I2 and contacts I3‘ and I4. The‘switch arm and contact I3 are insulated from plate ma‘ by the dielectric member l5 while con tact I4 is carried by‘ the switch arm. The switch arm is ?exed when the contacts are separated and normally urges the contacts together. This switch, together with the manually operated switch‘ I6 on case‘ 101), controls the ?ow of cur rent through an‘ electric heater‘ (not shown). As shown in Figs. _5 and 6, a bank of contacts I'Id, Ill) and He carried by a bracket I3 adjacent oné'end of the housing isadapt'ed to register with a bank of contacts I911, I91), and I90 on wall II. Fig, 5 is a transverse sectional view taken on the line 5-5 of Fig. 3 showing the manner in The banks of contacts are electrically insulated which electric current is supplied to the switch, 45 from the bracket I8 and wall I I by bars 2!! and 2 I. and When housing II) is mounted on wall I I, contacts Fig. 6 is a fragmentary longitudinal sectional I911, I91) and I90 extend through the opening I?d view taken on the line 6-6 of Fig. 5, in the base plate Illa and engage contacts I'la, In brief, the device is adapted to automatically 11b and He. control the ?ow of current through an electric 50 The manner in which electric current is sup“ heater so that the heater maintains the surround plied to the switch and the manner in which the ing space at a selected temperature. The ?ow of current ?ows through the switch to control the current to the heater is regulated by a switch heater is now described. Current from a suitable adapted to be opened and closed by a spirit wafer. source passes through the heater, thence through The wafer is adjustable so that it opens the switch 55 conductor 22 and contacts I9a and Na to a con 2,406,443 4 3 duotor 23 attached to the manually operated switch it‘. From the switch 16 the current passes through conductor 24 to contacts l3 and I4. When these contacts are engaged, the current ?ows through switch arm I2 and conductor 25 to contacts lib and Nib and thence through con ductor 26 back to the source. A small electro lytic condenser 21 connected at opposite sides of l3 and Hi, current can no longer flow to the heater. The heater remains deenergized until the thermostatic switch is again closed. This cycle is repeated over and over again to maintain a relatively constant temperature in the struc ture being heated. The particular temperature maintained depends upon the position of the wafer with respect to the pin 39. As described, the wafer may be selectively positioned by handle the switch by conductors 28 and 29 prevents arc ing between contacts l3 and iii when the switch 10 lit so that it operates the thermostatic switch at a predetermined temperature. Temperature is being opened or closed. The circuit also in scale d8 is correlated with the movement and cludes a pilot light 30 which is lighted when cur position of wafer 38 so that indicator handle rent ?ows through the heater. Current from 46 registers the temperature at which the wafer conductor 28 passes to the bulb 20 through con ductor 3i and thence through conductor 32, re 15 operates the switch. By providing the threaded connection between crosshead lid and shaft 45 sistor ‘$3, conductor 315, contacts llc—l9c and with a relatively long lead, ample adjustment of conductor 35 to a suitable ground. Bulb 30 is the wafer 38 is assured by rotation of the indi supported by the horizontal arm 35 which projects cator through 360° or less. from an essentially U-shaped bracket 3'! bolted By moving the wafer relative to a switch oper to plate 18a. Bulb 3i] extends through cover 10b 20 ating member, a highly e?icient and accurate as best shown in Fig, 1, and is clearly visible to construction is achieved. Moreover, his unique indicate whether the heater is operating. arrangement is so mechanically simple that the The thermostatic switch is automatically device is economical to fabricate. This con opened and closed by a spirit wafer 38 through the medium of a pin and a block of insulat 25 struction also permits ready and accurate ad justment of the wafer relative to the switch ing material Gil. The pin 3Q extends through and operating means and the adjustment can be easily is slidably supported by a hollow boss or hearaccomplished by a rotatable manual control in ing M on the bottom of plate iiia. Block 48, dicator. The switch is operative over a wide secured to the inner end of pin 39 by nut 39a, temperature range and can be accurately ad extends under the movable end of the switch arm justed by a relatively slight movement of the E2. The wafer 33 is supported within the struc manual indicator. ture being heated by a carriage which is slid It is to be understood that the form of the ably mounted to selectively position the wafer invention herewith shown and described is to with respect to the distal end of pin .39. The be taken as a preferred example of the same and carriage comprises a rectangular frame 42, guide rods 113 and a crosshead 44. Frame 42 carries the wafer and supports the outer end of pin 39, the guide rods are slidably supported by boss Ill and crosshead 44 connects the inner ends of the guide rods. The carriage is actuated by a shaft lit which screw-threadedly engages cross head M, as shown in Fig. 2. Shaft H5 is sup that various changes are contemplated and can be made Without departing from the spirit of my invention or the scope of the appended claim. Having thus described my invention, I claim: A thermostatic switch comprising a housing, a normally closed electrical switch within the housing, a wafer sensitive to temperature vari— ations, a pin slidably mounted between the switch and the wafer adapted to coact with the wafer through case i?b to receive the indicator knob or handle 46. A latching plate ill carried by 45 to open said switch, a frame carrying said wafer, guide rods slidably mounted in said housing sup bracket 3? has a forked end which ?ts into the porting said frame atone end, a crosshead within annular groove the in the shaft holding the the housing mounted on the other end of said shaft against longitudinal movement but permit guide rods, a dial calibrated with a temperature ting free rotation thereof. As shown in Fig. 1, indicator 6'5 moves across a temperature scale 50 scale mounted on the face of said housing, a rotatable shaft screw-threadedly engaging said 48 when shaft 45 is rotated. Since it is held ported by bracket 3i and its outer end, extends against longitudinal movement, rotation of the crosshead and extending through the center of shaft causes the carriage to slide relative to the said dial with an indicator mounted on its ex switch operating pin 39. Wafer 38 contracts when the media surrounding it cools. Pin 38 tending end, means for preventing longitudinal movement of said shaft whereby rotation of follows the Wafer and permits switch arm l2 to bring contacts l3 and I4 together. When this occurs current ?ows to the heater and the media around the wafer becomes heated. As the tem said indicator to any desired point on the cali brated dial adjusts the position of said water relative to the distal end of said pin causing the switch to be opened when the temperature perature rises, wafer 38 expands and pushes 60 of themedia surrounding said wafer corresponds pin 38 against switch arm l2. When the wafer has expanded sufficiently to separate contacts ' to that indicated on said dial. FREDERICK WV. STEIN.