US2674133A - Adjusting mechanism for thermostats - Google Patents

Description

' April 6, 1954 M. IRELAND ADJUSTING MECHANISM FOR THERMOSTATS Filed Sept. 25, 1950 INVENTOR.

BY aw w. "1.24.

HTTORNEY Patented Apr. 6, 1954 ADJUSTING MECHANISM FOR THERMO STATS Murray Ireland, Elgin, 111., assignor to McGraw Electric. Company, Elgin, 111., a corporation of Delaware Application September 25, 1950; S'erialN'o. 186,591 1 Claims. (01. Me-6M);

The present invention relates to manual adjusting devices and more particularly to the temperature adjusting mechanism of electric irons;

A thermostatically controlled electric sad iron is customarily provided with a manual control for setting the temperature at which the thermostat tends to holdthe iron. It is desirable that the handle or'knob of such a control have an indicator for showing thetemperature for which it is set, that it be adjustable with respect tothe mechanism it controls for making the indication correct, that it be ornamental and to that end that it conceal its mechanism. Further it is desirable, for ease of manipulation, that the adjusting knob be located on, or close to, the gripping part of the handle of the iron and that the knob fit into the lines thereof. Finally it is desirable that the knob and mechanism be simple of construction and easy of assembly, disassembly, and adjustment.

It is an object of the present invention to provide an improved control mechanism having the foregoing characteristics, the provision of a cheap and simple, yet reliable and eifective, construction for an adjusting mechanism, the provision of a simple and ornamental construction for a manual control knob, and the provision of animproved sad iron construction. These and other objects and advantages of the invention will appear from the following description. of the specific embodiment that I now prefer, which illustrates the manner in which the invention may be put into practice. In the drawings:

Figure l is a sectional elevation of the forward part of'an electric flatiron embodying my present invention;

Fig- 2. is an exploded view of; certain parts of the structure of Fig. 1;

Fig. 3 is a pictorial view of the complete iron of Fig. 1;

Fig. 4 is a bottom view of the adjusting knob.- 62; and F Fig. 5' is a pictorial view of the bracket 20 of The sad iron of Fig. 1 includes a body portion that comprises a metal sole plate [0, a metal top plate i2, an electric heating element Hi therebetween, and a shell [5. The top plate I2 makes metal-to-metal contact with the sole plate H) at the peripheral edges and has further good thermal connection therewith through central ,metal blocks it of which one is shown in Fig. 1. This construction is described and claimed in the co-pending application Ser. No. 586,099, filed August 27, 1945, now Patent No. 2,585,928, issued February 19. 1952.

A bracket 20, supported on the plug lit 'by means of a screw l8, includes a bottom strap 2.2, side pieces 24 and a top piece 26 An adjustable switch arm 30- rocks on the ridge of a bend of the bottom strap 22 and is held in position bya ball-shaped stud 3 2 that sets in a hole in the strap 22. An adjusting screw 34', which is threaded into. a bushing 36' in the part 26, controls the position of this arm 30 and a spring 38 holds it against the. screw. The. heating element is controlled by the switch contacts 42. on the arm 30, and M onan arm 46 which is part of a temperature-responsive mechanism not fully shown here but described and claimed in myco-pend-ing application, Ser. No. 186,593, filed September 25, 1950-. The temperature at which this control mechanism tends to hold the sole plate i0 is thus determined by the setting of the screw 34.

Rising above the body of the iron is a handle 50 (see also Fig: 3)'* which includes an approximately horizontal fore-and-aft grip portion 52, a rear column 5' l and a front column 58'. Atop the front column 56 is a substantially flat seat 6G for accommodating a control knob or handle 62. This seat liesforward of the grip portion 52 and is stepped below the top surface thereof so that the front end of the grip portion provides. a wall-likeportion 6t rising alongside the wall. 62 and extending slightly thcreabove. A shaft- 66 provides a driving connection between the knob. 62 and the adjusting screw 34 and helps to retain the knob 62' in place. A spring member 68 sets in a recess T0 in the wall 64 and overlies the knob 62 in the top of shaft 66 for helping to hold them in place. The construction of these,v parts is best seen in the exploded pictorial view of Fig. 2-. The screw 34 includes a straight round guide portion T4 topped by a T-shaped key 16. The shaft 66 at its lower end has a bore. for fitting the guide portion 14 of the screw 34' and also alongitudinal slot 18 for receiving the key portion 16 and thereby providing driving connection between the's-haft and screw. The knob 62 has a central hole through which the shaft 65 extends. A round bore-like recess at the top of the knob has spline-like longitudinal serrations for engaging the points of a star at the top of the shaft 66. The dimensions of the parts are such that when the knob 62 is in place the shaft 66 may be extended therethrough to make driving engagement with the key 16 of the screw 34 without the star 80 entering the counterbore of the knob. With the parts held at this position the knob may be rotated with respect to the shaft 65, and therefore with respect to the thermostat adjusting screw 34, to the required position. Then the shaft 66 may be lowered and the star 80 seated in the counterbore of the knob where it fits tight to provide a positive connection and to prevent rattling. Temperature values are marked about the periphcry of the knob, and the forward end of the spring 68 is pointed to serve as an indicator for cooperating with the temperature indications on the knob to show the temperature setting of the thermostat. As may be seen in Fig. 1, the hollow knob includes an interior radial fin 84 which abuts the head of a screw 86 for limiting the rotation of the knob 62 to slightly less than one complete revolution.

The spring key 68 is ornamental, conceals the shaft, the star and splined counterbore and yet constitutes a simple and easily assembled construction. In the manufacture of irons accord-. ing to this invention the adjusting screw 34 may first be set to the position at which it barely opens the contacts 42 and 44 with the sole plate at room temperature. Then a partial turn of the screw will bring the setting into the working range of the iron. The iron can then be connected to power, the temperature at which the sole plate operates can be measured, the knob 62 can be set to indicate that temperature and, without turning the screw 14 the shaft 66 can be seated in place. Finally, the spring key 68 is snapped into place.

The present invention is capable of modifications and variations within the scope of the appended claims.

Iclaim:

1. In combination in an adjusting mechanism for a thermostatic control or the like, a rotatable control member, a rotatable connector keyed thereto for rotating it but slideable axially therealong, a handle engageable by said connector but disengageable by motion of said connector in one direction axially of said control member, a stop for limiting movement of said handle in the opposite direction, a stop on said handle for limiting motion of said connector in said opposite direction, and a disengageable stop for limiting motion of said connector in said one direction and for preventing its disengagement from said handle.

2. The combination of claim 1 wherein said rotary control member is a screw and the freedom for axial relative movement between said screw and connector accommodates the axialprogression of said screw when it is turned.

3. In combination, a body, an adjustable rotatable control member therein, a rotatable handle outside said body, means providing an abutment for limiting the inward motion of said handle, an elongate connector extending through said handle to said control member and having near its outer end an enlarged key portion for engaging said handle for limiting inward motion of said connector and for making rotary driving connection with said handle, said connector having a key portion for making rotary driving connection to said control member while permitting axial movement, said connector being movable outward a small distance for disengaging its rotary driving connection from said handle, but requiring a greater outward movement for disengaging its rotary driving connection from said control member, and a disengageable stop for limiting outward motion of said connector and for holding said key portion thereof in rotary driving connection with said handle.

4. In combination in an adjusting mechanism for a thermostat of an electric iron or the like, a manual adjustment knob, a body having a seat for said knob and having also a part rising alongside said seat for flanking said knob and a recess extending laterally into said part, a spring key supported in said recess and extending out over said knob for holding it on said seat, and rotatable means in said body connected to said knob for rotation thereby.

5. The combination of claim 4 wherein said handle carries indicia relating to the setting of the thermostat and said spring key constitutes a pointer for cooperating with said indicia.

6. The combination of claim 4 wherein the connection between said manual knob and said rotatable means includes a, shaft extending through said knob and into said body, wherein said shaft is displaceable outward from'operating position, and wherein said key also overlies said shaft and holds it in said operating position.

7. The combination of claim 4 wherein the driving connection between said manual knob and said rotatable means includes a shaft extending through said knob and into said body, said shaft is axially shiftable outward therethrough, said shaft has an enlargement at its outer end, said knob has a non-circular counterbore at its outer side for receiving said enlargement of said shaft for limiting inward axial motion of said shaft and for keyin said knob to said shaft for rotary driving, and wherein said spring key bears inward on said shaft for holding said shaft and knob in place.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,225,236 Shaw Dec. 17, 1940 2,299,462 Clark Oct. 20, 1942 2,339,407 Horton Jan.-18, 1944 2,403,115 Olving July 2, 1946 2,437,785 Mucher a Mar. 16, 1948 2,473,081 Vaughan l June 14, 1949 FOREIGN PATENTS Number Country Date 600,051 Great Britain f Mar. 30, 1948

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