US1884232A

US1884232A - Electrical heating device for curling tongs

Info

Publication number: US1884232A
Application number: US408065A
Authority: US
Inventors: Rehm Alfred
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch AG; Robert Bosch GmbH
Priority date: 1928-11-24
Filing date: 1929-11-18
Publication date: 1932-10-25
Anticipated expiration: 1949-10-25

Description

Oct. 25, 1932. A. REHM 1,884,232

ELECTRICAL HEATING DEVICE FOR CURLING TQNGS Filed Nov. 18. 1929 is i Patented Oct. 25, 1932 ALFBED Km, 01' STUTTGABT, GERMANY,

PATENT OFFICE ASSIGNOR 1'0 ROBERT BOSCH AKTIENGE- SELLSGEAFT, OF STUITGART, GERMANY ELECTRICAL HEATING DEVICE FOR CURLING TONGS Application filed ll'ovcmber 1a, 1929, Serial No.

The-present invention relates to electrically heated curlingtongs.

In curling tongs having a built-in heating resistance, the temperature of the curling tongs is usually regulated by an adjustable series resistance, which is housed in a container secured to the wall. This series resistance is disadvantageous as it consumes considerable power. Also the adjustment through the series resistance does not always correspond to the actual temperature of the the curling tongues when in use, as this is also dependent on the momentary heat delive a of the curling tongs.

According to the present invention a temperature controlled switch is installed in the heating tong element of a curling tongs which can automatically switch the current for the heat resistance oif and on as the temperature rises or falls.

One form of construction of the invention is illustrated by way of example in partial section in the accompanying drawing.

Inserted in .the hollow heating tong element-1 of a air of curling tongs is a tube 2 of zinc or ot er metal of relatively high coelficient of expansion into which an insulated tube 3 is introduced.

Mounted in the upper end of the tube 2 is a rod 4: of quartz glass or the like material of relatively low coeflicient of expansion. A heating resistance 5 is wound on the rod 4.

Mounted on the free end of the rod 4 is a boss 6 of iron or other electrical conducting material provided with outer threads on which is screwed an iron sleeve 7. A pin 8 which has a flange-shaped stop 9 and a contact head 10 is disposed within the boss 6 and sleeve 7. The free end of the sleeve 7 is bent over to secure an annular disc 11. A helical spring 7' is tensioned between the flange of the sleeve 6 and the stop 9 of the pinl8 and tends to force the stop 9 against the annular disc 11.

A pin 14 is screwed into a tube-shaped eX- 408,065, and in Germany Iovember 24, 1928.

tension 13 of the tube 2 and carries an insulated contact or bridge 16 through an intermediate insulator 15 the contact being of truncated conical form. A contact spring 17 secured to the end of cylinder 2 but insulated therefrom is adapted for 'contact with the bridge 16 and is connected to a source of current by means of a lead 18.

The screw pin 14 has a head '20 provided with divisions 19 and'the position of the divisions can be read ofl the end of an indicator 21, secured to the heated tong element 1.

During installation the position of the pin 8 relative to the contact 16 can be adjusted by screwing the collar 7 onto the sleeve 6. One end of the heat resistance 5 is connected to the sleeve 6 and through this to the pin 8; the other end of the heat resistance being attached to-a lead 22. a

As the temperature of the heating resistance rises the zinc tube 2 expands more than the quartz rod 4. The pin 8 follows the expansion of the zinc rod 2 until the stop 9 abuts against the annular disc 11. If the temperature of the heated tong element rises still further,thenthe contacts 10 and 16 separate on the further expansion of the Zinc rod and the heating resistance is thereby switched ofi.

During the subsequent cooling of the curling tongs the zinc rod 2 again contracts so that the contacts 1) and 16 again touch.

By screwing out the screw pin 14., the position of the contact 16 relative to the contact 10 is altered in such a way that the opening of the pair of contacts is efiected and a lower temperature than formerly is provided. The position of the screw pin 8 canbe read off by means of the divisions 19 gauged according to the temperatures.

The form of construction shown by way of example has the advantage that the heat acting on the wall of the heated tong element influences the heat switch directly and the heat arising during the practical use of the curling tongs is thereby controlled.

In a modified form of construction the tube 2 may itself form a heated tong element.

Again a difierently constructed heat switch can be installed in the curling tongs, for example a switch working with a bimetallic spring.

I claim:

1. An electrical heater for'curling tongs comprising a hollow casing, a heating resistance within said casing, two longitudinal members of different heat coefficient of expansion connected together at one end, a pair of switch contact elements in series with said resistance each contact element being connected to the free end of one of said longitudinal members and an adjustable bridging member between said switch contact elements.

2. An electrical heating device for curling tongs comprising a cylinder formed of ma: terial of relatively high temperature coefiicient of expansion, a rod within and connected at one end to said cylinder formed of material of relatively low temperature coefficient of expansion, a heating resistance wound upon said rod. a resiliently axially displaceable contact element at the free end of said rod and in series with said resistance, means for limiting the displacement of said contact element in one direction relatively to the rod a resilient switch contact element at the free end of the cylinder in series with the resistance and an adjustable bridge intermediate of said switch contact elements.

3. An electrical heating device for curling tongs comprising a cylinder formed of material of relatively high temperature coefiilower temperature coeflicient of expansion than said casing and being mounted at one end within said casing and having its free end facing said insulated contact, a resilient contact element mounted on the free end of said rod, an adjustable bridge connecting said contact elements, and a heatin winding wound upon said rod and having its circuit completed through said contacts and bridge.

In testimony whereof I have hereunto afiixed my signature.

ALFRED REHM.

cient of expansion, a rod within and connected at one end to said cylinder formed of material of relatively low temperature coefiicient of expansion, a heating resistance wound upon said rod, a resiliently axially displaceable contact element at the free end of said rod and in series with said resistance.

means for limiting the displacement of said contact element in one direction relatively to the rod, and a switch contact element at the free end of the cylinder in series with the resistance.

4. An electrical heating device for curling tongs and the like comprising a hollow cylindrical casing, an insulated contact mounted in one end of said casing, a rod having a lower temperature coeflicient of expansion than said casing and being mounted at one end within said casing and having its free end facing said insulated contact, a resilient contact element mounted on the free end of said rod and cooperating with said insulated contact, and a heating winding wound upon said rod within said casing and having its circuit completed through said contacts.

5. An electrical heating device for curling tongs and the like comprising a hollow cy-v lindrical casing, an insulated contact mounted in one end of said casing, a rod having a