DE1176736B - Electric heat switch - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: H 02 c

German class: 21c-40/05

Number: 1176736

File number: R 27299 VIII d / 21 c

Filing date: February 10, 1960

Opening day: August 27, 1964

The invention relates to an electrical thermal switch with a resilient one clamped on one side Contact arm, which is biased in the opening direction in the on position, opposite at its free end the moving contact carries a U-shaped armature and approximately in the middle by pressing one Heat sensor can be actuated against the force of a magnet that always acts in the closing direction.

In known switches of this type, the opening movement of the contact arm is limited caused by a stop and the adjustment is made by adjusting a fixed contact. Included impact and bouncing stresses arise during the opening process, the adjustment is difficult, and the mechanical stresses on the contact arm with regard to its prestresses are undesirable high.

If the centering of the Bend the mass of the same to the stop on impact, whereby a proper operation of the Switch becomes impossible.

Such switches are used to interrupt relatively strong alternating currents (250 volts, 15 to 20 amps). In this case, the opening time of the switch should be about half a current period be, and the distance between the contacts must be large enough after this time to a Prevent arcing. For this reason, in the previous switches, the movable one is used Contact carrying resilient contact arm stretched until its tension is greater than that The magnet is attracted and it moves against the fixed stop by a sudden deflection will. Such a construction has when using the switch for thermostating systems the disadvantage that when the system to be monitored becomes hot and the switch is switched off the resilient contact arm is stretched and experiences a permanent change in shape, whereby the The operating point for the switch-off set by the adjusting screw is unintentionally changed.

The special facilities provided to eliminate this disadvantage are cumbersome and expensive, and they increase the space requirement of the heat switch.

The purpose of the invention is to eliminate these disadvantages and to create a simplified, improved one electrical heat switch with safe operation, easy adjustment and possible little space required. This is achieved by the fact that in the case of a heat switch, the pre-electrical Heat switch

Applicant:

Satchwell Controls Limited,

Slugh, Buckinghamshire (UK)

Representative:

Dipl.-Ing. A. Berglein, patent attorney,

Munich 22, Widenmayerstr. 49

Named as inventor:

David Hay Surgeoner, Beaconsfield,

William Frederick French,

Slough, Buckinghamshire (UK)

Claimed priority:

Great Britain March 2, 1959 (7227)

mentioned type the limitation of the opening movement of the contact arm instead of by a stop the natural springiness of the contact arm is determined, the force of which initially increases during the opening movement Zero and then changes to an opposite value, and that the adjustable in its position Magnet and the armature are designed so that even if the contact arm overshoots during the Opening process, the resulting magnetic force acting in the closing direction is not reversed. Included the parmanent magnet is attached to a resilient arm that can be bent out by adjusting means. The actuator pressing on the contact arm is in a manner known per se by one of a temperature sensor actuated and actuated by an actuator can be influenced drive lever.

According to the invention, there is neither a fixed stop nor a special device for reducing it the spring tension required for the switch. Rather, you can use the resilient contact arm unhindered move beyond the normal open position without affecting the cantilever resilient switching lever and the force of attraction of the magnet coordinated setting of the operating point of the contact opening changes. Through this there is the advantage that impact and bounce stresses avoided during the opening process and an adjustment that better corresponds to operational safety by adjusting the magnet instead of the fixed contact is made possible, whereby

409 658/405

also the mechanical stress on the contact arm with regard to its preload in the On position is lower. Furthermore, in addition to a simplified structure, a significantly lighter one results Adjustment of the switch because the fixed contact need not be adjustable and only for the holder of the magnet simple adjustment elements are required, which provide an exact, constant definition the operating point and range of the switch.

In the drawing, an embodiment of the subject matter of the invention is in connection with shown by a thermostat. It shows

F i g. 1 shows an embodiment of the switch according to the invention in a side view,

F i g. 2 shows the same switch in section along the line H-II in FIG. 1.

From the drawing, in particular FIG. 1, is to see that a stationary main contact part 1 is mounted on a frame 2 without adjusting means. A movable contact 3 and a double magnet armature 4 are on a resilient contact arm 5 attached. A permanent magnet surrounded by the double magnet armature 4 is on a relative basis rigid, limited resilient lever 7 attached, next to which a rigid arm 8 as a fixed Stop is arranged. The corresponding ends of the resilient levers 5 and 7 and the rigid arm 8 are separated from one another at one end by spacers or spacers and by means of a Screw with nut 9 rigidly attached to the frame 2. The basic position of the permanent Magnet 6 opposite the double magnet armature 4 is by means of a seated in the rigid arm 8 and against the limited resilient lever 7 pressing stud 10 adjustable, the operating point of the Switch by adjusting this stud screw

10 is set. The deflection of the resilient contact arm 5 into the open position for the contact parts 1, 3 caused by the difference between the switch opening and closing temperatures is shown in the point

11 brought about by a pressure pin 21 mounted so as to slide in the longitudinal direction.

The magnetic force which begins to open on the part of contacts 1, 3 in this way, Both the increased mechanical force and the spring preload force of the contact arm 5 are reduced as well as the resulting opposing magnetic force, the resulting magnetic However, force initially decreases faster than the increased mechanical force, which causes the movable Contact 3 is opened at high speed.

The increased mechanical force then decreases faster than the resulting magnetic force Force until the movable contact 3 assumes a position in which the resulting magnetic Force comes into equilibrium with the opposing mechanical force, whereby the contact 3 is brought to a standstill and held in this open position.

If the pressure pin 21 is above the previously described position which causes the contacts 1, 3 to open if the contact arm moves out or swings over in the opening direction, the reversal of the resulting magnetic field prevents the spring tension force of the contact arm now changes into an opposite value which counteracts the opening direction to an increasing extent and in cooperation with the permanent magnetic attraction force in the closing direction the underside of the double anchor 4 is not so close to the underside of the magnet 6 can approximate that a reversal is taking place.

If the pressure pin 21 is now released, it slides downward, as can be seen from the drawing mechanical force is reduced and the switch closes again.

In a preferred embodiment of the invention, the magnet 6 is 11 mm long, 8 mm wide and 3.6 mm thick and made of Alnico (III) alloy. Each armature leg 4 corresponds in length and width to the magnet 6.

The resilient contact arm 5 consists of a copper alloyed with 0.4% beryllium and is about 8 mm wide, about 0.25 mm thick and has an effective length of about 19 mm; the pressure pin 21 engages in the middle the effective length of the shift lever 5 on this

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Double anchor 4 acts, which of the upper side 45 to. The limited resilient lever 7 for the magnet

of the magnet 6 is facing, the part of the double armature 4 acts, which is the lower side of the magnet 6 is facing, contrary, the resultant of these two magnetic forces on the movable contact 3 is effective in the closing sense. The resulting magnetic force that acts on the movable contact 3, normally exceeds that on this contact 3 and the Low-contact mechanical force and 6 is made of phosphor bronze and is about 8 mm wide and 0.7 mm thick.

The parts of the switch shown in Fig. 1 are attached at a point 12 on the frame 2 (Fig. 2). The frame 2 contains an elastic pressure cell 13, which with a liquid-filled tube 14 serving as a temperature sensor through a capillary Line is in communication. The elastic wall of the pressure cell 13 is ver with a pressure bracket 15

decreases steadily if contacts 1, 3 open. 55 see, which with a rigid lever-like over-

In the on position, the resilient contact arm is in cooperation with the opening member 16. The from

direction of tension biased, wherein the biasing force of the point 12 contains the side of the frame 2 facing away

during the opening movement initially to zero and a plate 17 in which a temperature setting

then goes to an opposite value. medium-sized regulating screw 18 with one hand

The switch is opened by the fact that a pressure 60 has 18 a is adjustable. The regulatory

pin 21 depending on a heat sensor by a sufficiently large travel sliding upwards is moved, whereby the on the movable contact 3 by the suspension of the resilient contact arm 5 acting mechanical spring preload force in the same direction over the strength of the this contact 3 counteracting magnetic force is also increased. As soon as the The adjusting screw 18 is in a threaded bush 19 that is releasably fastened in the plate 17 by means of a spring washer 20 guided and acts on the lever-like transmission member 16 as an adjustable stop.

The end facing away from the pressure bracket 15 of the lever-like transmission member 16 is with the Pressure pin 21 in drive connection, which protrudes through the frame housing 2 and at point 11

acts on the resilient contact arm 5. The adjusting screw 18 acts on the lever-like transmission member 16 in its longitudinal center between the pressure bracket 15 and the pressure pin 21. The position of the Adjusting screw 18 sets the operating point of the switch as a function of the pressure cell 13 and enables it the setting of the setpoint of the temperature of a temperature control or regulation device or a thermostat.

Claims (3)

Patent claims: 1. Electrical heat switch with a springy contact arm clamped in on one side, the is biased in the on position in the opening direction, at its free end opposite the movable contact carries a U-shaped armature and approximately in the middle by pressing a Heat sensor can be actuated against the force of a magnet that always acts in the closing direction is, characterized in that the limitation of the opening movement of the contact arm (5) is determined by the natural springing of the contact arm instead of a stop, their force during the opening movement first to zero and then to an opposite one Value passes, and that the position of the adjustable magnet (6) and the armature (4) are so designed are that even if the contact arm overshoots during the opening process, the resulting magnetic force acting in the closing direction does not turn back. 2. Heat switch according to claim 1, characterized in that the permanent magnet (6) is mounted on a resilient arm which can be bent out by adjusting means (10). 3. Heat switch according to claim 1 or 2, characterized in that the on the contact arm (5) pressing actuator (21) in a known manner by one of one Temperature sensors (13, 14) actuated and controlled by an actuator (18) drive lever (16) is actuated. Considered publications:
Swiss Patent No. 271496;
British Patent No. 658,705. 1 sheet of drawings 409 658/405 8.64 © Bundesdruckerei Berlin