US1704406A - Thermostatic switch - Google Patents

Description

J as

proceeds and which involve the provision o Patented Mar. 5, 1929.

UNITED STATES lflt isltfi PATENT CARL T. PENTON, OF BUFFALO, NEW 'YGIRK.

'rnnnmosrn rxc swrron.

Application filed December 6, 1923. Serial No. 878,840.

This invention relates to improvements in thermostatic switches, proposing a switch which is available for the automatic control, according to temperature variations, of electrical appliances or apparatus, such as ovens, water heaters and the like, where it is desirable that the temperature be maintained at a certain approximate degree or within a certain range.

The principal objects of the invention are to secure a quick make and break of the cooperating electric contacts whereby destructive arcing is eliminated and to provide for this purpose mechanism of simple structural character which will be at all times certain and reliable and will not be liable to derangement.

A further object is to promote facility in the fitting and removal of the operating parts relatively to the structure with which the thermostat is associated by providing for the assembly of such parts as a self contained unit through which the circuit to be controlled is completed.

' A further object is to provide facility in regulating the degree of temperature at which the circuit will be opened and below which it will be closed.

With the above objects in View the invention consists generally in certain novel features of structure and combination which will be pointed out in detail as the description friction means for retarding the action of the thermostatic spring, provision for the removable mounting of the operating parts as a self contained conducting unit, and provision for the regulation of the critical temperature degree or range by the movement of an indicating part and without the necessity of any manipulation or adjustment of the co-opersting contacts.

An embodiment of the invention is illustrated in the accompanying drawing wherein: I Figure 1 is a longitudinal sectional view of the switch.

' Figure 2 is a front elevation thereof.

Figures 3 and 4 are sectional views on the lines 33 and 44 of Figure 1.

Figure 5 is a sectional view on the line 5-5 of Figure 3.

Figure 6 is a sectional view on the line 6-6 .df Figure 1.

The switch is supportedby the wall A of the electrical appliance to be controlled, such for example as a water heater,'and is subject to the heat developed within the chamber of such appliance. The casing in which the operating mechanism is enclosed is preferably made in two parts, namely the casing proper as 1 and a sleeve-like extension theremade as separate parts, the casing having a collar 3 projecting from its rear wall and fill? ting over the front end of the extension upon 1 which it is secured by a screw 4. In order to prov de access to the operating parts the front wall 5 oi the casing is removably secured, as by screws c, to the body of the cas-,

ing.

The support for the operating parts consists of a metallic frame Z which is secured by fastening bolts 8 and i) to the rear wall or the casing 1. The bolts 8 and '9 are provided on their projecting rear ends with securing nuts 10 and are available as binding posts for the connection or the terminals 12 of the wires which are joined to the terminals of the heating element or other electrical receiving device. The frame 7 is insulated from the casing 1 by a plate 13 of suitable insulating material which is fitted between said frame and the rear wall of said casing and is supported by contact with the frame 7 and is insulated from the casing 1; the bolt 9 is insulated both from the frame and from the casing.

Any suitable make-and-break device may be employed, that shown being preferred and consisting of a laterally arranged stationary contact 14 connected to the bolt 9 and cooperating with a contact 15 provided on a movable bar 1-6. The frame "l is provided along its upper side with a pair of spaced lugs l? and i8 whereof the 11'' carries the contact let (from which it is suitably insulated) and the lug '18 serves "for the attachment, as bye screw 19, of an indicating scale 20 which bridges said lugs and cooperates with an indicating linger 211, the scale 20 and finger 21 being visible through a window 22 in the front wall 5. t

The bar 16 is operated by a thermostatic spring 23, as shown ahelical y wound spring, and projects radiall from a head 24 mounted fast at one end or a longitudinal sleeve 25 which functions as a shaft and is mounted f the bolts 8 and 9. The belt 8 is in electrical lit) upon a longitudinal bar 26. The bar 26 is supported for turning adjustment with reference to its axial center in a thimble 27 provided at the lower side .of the frame 7 and, together with the sleeve 25, projects into the extension 2. The bar 26 is provided at its rear end with a head 28 and the sprin 23 which is located in the extension 2 beyon the sleeve 25 is secured at its ends to said sleeve and said head. The bar 26 is held against displacement under the pressure of the spring 23 by a nut 29 which is fitted at the front end .of the bar upon a threaded portion 30 and is backed by a suitable cushioning washer 31, in turn backed by the thimble 27.

The thimble 27 also provides a bearing for an adjusting disc 32 which is mounted behind said thimble upon the bar-26 to which it is made fast in any suitable manner and which carries the finger 21. The disc 32 is pressed against the rear face of the thimble 27 by the head 24 (under the pressure of the spring 23) and may be turned by the finger 21 in either direction to eflect a corresponding movement of the rod 26 and a consequent regulation of the tension of the spring 23. A friction disc 33, preferabl composed of vulcanized fiber is fitted on t 1e rod 26 between the head 24 and the disc 32, the friction disc being backed by the adjusting disc and having a flat and wide contact with the adjacent face of the head 24 which is pressed against the friction disc by the spring 23.

The extension 2 is preferably closed at its rear end by a head 34 and the spring 23 is ar-' ranged in the portion of the extension which projects into the chamber provided by the wall A. where it is sensitivel responsive to temperature variations in sai chamber. Below a determined degree or range of temperature the spring'23, acting on the sleeve 25, and through it on the bar 16 will cause the contact 15 to engage the stationary contact 14. Above such degree or range of temperature the s ring 23 similarly causes the contact 15 to disengage the contact 14. The degree or range of temperature to be maintained is determined by the position of the finger 21 with reference to the scale 20, the movement of said finger along said scale being'effestive, through the rod 26. to regulate the tension of the spring whereby if the tension be decreased the spring will disengage the contacts 15 and 14'at a lower temperature and if the tension be increased the spring will disengage such contacts at a higher temperature. The finger 21 is adjusted manually glong the scale 20, the cover 5 first being removed as is obvious.

The movement of the bar 16 to effect the engagement or disengagement of the contact 15 relatively to the contact 14 is quick and in the nature of a snap action whereby destructive arcing, which might otherwise be due to the high tension currents employed, is

V cor-operating avoided. This snap action of the bar 16 is secured by the provision of the friction disc 33 which, engaging the head 24, acts as a brake .on the sleeve 25 in opposition to the spring 23. It follows that before the spring 23 can produce a movement of the bar '16 it must'store suflieient power to overcome the braking effect of the disc 33 with the result that the bar 16 can have no gradual movement but is moved quickly or snapped in either direction accordingly as it is being operated to engage or disengage the contacts 15 and 14.

The operating parts are assembled to constitute a self contained'conducting unit which may be removed from and inserted into the casing 1 and its extension 2. The circuit of the heating element or other electrical receiving device is closed through the terminal 9, contacts 14 and 15, bar 16, sleeve 25, rod 26, disc 32, frame 7 and terminal 8. The frame 7 is the support for thevoperating unit and such unit is removed by first removing the front Wall 5 of the casing 1 and then disconnecting the bolts 8 and 9. If dcsiredthe casing 1 and the operating unit may be removed together from the extension 2 after first backing off the screw 4.

Having fully described my invention, I

claim:

an indicating scale and co-operating finger constituting companion relatively movable elements, and operative connections between one of said elements and said rod whereby a.

movement of said element relatively to its companion element effects an adjustment of said rod.

2. In a thermostatic switch, the combination of a movable contact part, a thermostatic spring for operating the same, means including an adjustable rod for regulating the tension of said s ring, an indicating scale and nger constituting companion relatively movable elements, operative connections between one of said elements and said rod whereby a movement of said element relatively toits companion element efi'ects an adjustment of said rod, and means acting with braking effect to oppose the action of said spring whereby the latter must store power to a certain degree in order to operate said contact part.

3. In a thermostatic switch, the combination of a supporting part provided with a thimble, a rod mounted in and projecting from said thimble, a sleeve mounted on and supported by said rod, a thermostatic spring connected at its ends to said rod and sleeve, the rod being adjustable whereby to regulate the tension of said spring, and a movable contact part actuated by said sleeve.

4. In a thermostatic switch, the combination of a supporting part provided with a thimble, a rod mounted in and projecting from said thimble, a sleeve mounted on and supported by said rod, a thermostatic spring connected at its ends to said rod and sleeve, a movable contact part actuated by said sleeve, and means acting with braking effect to oppose the action of said spring whereby the latter must store power to a certain degree in order to operate said contact part.

5. In a thermostatic switch, the combination of a supporting part provided with a thimble, a rod mounted in and projecting from said thimble, a sleeve mounted on and supported by said rod, a thermostatic spring connected at its ends to said rod and sleeve, the rod being capable of adjustable movement, an indicating finger connected to said rod for adjustably moving the same, a scale with which said finger co-operates, and a movable contact part actuated by said sleeve.

6. In a thermostatic switch, the combination of a supporting part provided with a thimble, a rod mounted in and projecting from said thinible, a sleeve mounted on and supported by said rod and provided with a head, a movable contact part operated by said sleeve, a thermostatic spring connected atv its ends to said rod and sleeve, and a friction disc fitted upon said rod and pressed against said head with braking effect.

7. In a thermostatic switch, the combination of a supporting part provided with a thimble, a rod mounted in and projecting from said thimble, a sleeve mounted on and supported by said rod, a thermostatic spring connected at its ends to said rod and sleeve, the rod being capable of adjustable movement, a finger connected to said rod and by which said rod may be adjusted, said sleeve being provided with a head, a friction disc fitted upon said rod, and engaging said head with braking effect, and a movable contact part actuated by said sleeve.

8. In a thermostatic switch, the combination of a movablecontact part, a thermostatic spring for operating the same, means for regulating the tension of said spring, and a frictional connection between said movable contact part and a relatively stationary part, said connection acting with braking effect to oppose the action of said spring whereby the latter must store power to a certain degree in order to operate said contactpart.

9. In a thermostatic switch, the combination of a movable contact part, a thermostatic spring for operating the same, an indicating scale having a movable element, means actuated by said element for regulating the tension of said spring, and means acting with braking effect to oppose the action of said spring whereby the latter must store power to a certain degree in order to operate said contact part.

In testimony whereof I atfix my signature.

CARL T. PEN TON

Images