US2615082A - Vulcanizing apparatus - Google Patents

Description

Patented Oct. 21, 1952 VULCANIZING APPARATUS Peter J I ,Mamola,'Astoria, N..Y., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation ofNew York Application July 19, 1950,Serial No. 174,635

' 10 Claims. 1

This inventionhrelates. to vulcanizing apparatus and more particularly to an indicating and control circuit for electrically heated vulcanizers.

In vulcanizing. apparatus, it is necessary to subject the article being vulcanized to a predetermined amount of heat, after which the heat source must be disconnected and the article allowed to cure beforebeing exposed to the atmoshphere.

Itis an object of thisinvention to providenew and improved means for automatically deter- .mining andindicating the vulcanizing. and ouring cycles during a vulcanizing operation.

In accordance with a preferred embodiment of the invention, an electrically heated mold is provided wherein the power circuit thereto is so connected thr ugh -a double-contact circuit sponsive element and resistance in. parallel with the resistance heating elements in one of the mold sections, in such. a manner that-the thermal element will close whenthe temperature in the mold reaches a predetermined maximum value. This action results in a lowered effective resistance, and thus a higher current flow through the circuit breaker, therebycausing thebreakerv to tripto its-second set of contacts.

A more complete understanding of the invention may be had by. referring to. the following detailed description,-when read in conjunction with the accompanying single figure drawing which schematically represents a, vulcanizing mold and a circuit for controlling-the heating of the mold .in accordance with the invention.

:The'apparatus consists of a lower fixed mold section having a lower. mold cavity H, and an upper movable mold'section l2 having an upper mold cavity I3. The upper mold cavity 13 "is adaptedto be moved into register with the =lower7moldcavity l l :by means. of ahingeduconnection l4, and such movement} results .in the closure of a normally'open microswitch I which initiates energization .of electrical heating elements carried by the two moldsections.

.For the purpose of heating the mold sections a pairlof resistance heatingielements'i'l)and 21 F are provided, which elements are disposedin rthermal relationship with,-but electrically insulated from, the upper and' lower mold sections Willand l 2rrespectively. .The;heatingelements:2G sand 3.2l are preferably :::connected in .parallel across a source of current 22 with one side of the parallel connection being completed directly to the source 22. The other side of the parallel connected heating elements is adapted to be connected tothe source 22 through an actuating .coil 23 ofa single pole double throw circuitbreaker .24. provided withtalternate fixed contacts 25 and 26 and a movablecontact 21. The circuit through .thecoil 23 to thesource 22 is completed Zlthen remains incontact with contact 26 until it, is manually reset.

Inorder to determine theamount of heat which is applied to theyarticle being vulcanized in the cavities-ll and [3, an inverse'thermoswitch 30 is provided, which thermoswitch is characterized by'its :ability to provide a closed electrical circuit when the temperature thereof reaches a predetermined maximum value. vThe thermoswitch 30 may be mounted in thermalrelation :with either .one of themold sections H1 or l2,..and;is hereishownasmounted in;,the-sec- .The thermoswitcho30- is connected in series-with a resistance 3 I. having an ohmic; value relatively smaller than-the resistance of either of the heating elements-2D. and 2|. Theseries connected thermoswitch and resistance 3 l are connected inv parallel with the heating (elements 20 and 2!, and an indicator lamp 32 is -likewise connectedin parallelwith the elements-20 and Thus it will vbeobserved that. the lamp -32 will be lighted during the time that the elements 20 and .2! are energized, and the closure of rthermoswitch30 results in completionof a, circuit through the; resistance 31 -.thus increasing the current through .coil .23 to. such -an ..extent "that movable contact-21 is, switchedfrom itscontact with fixedcontact 25 to contactwith fixed contact 26, thereby stoppingthe fiowof current from the source 22 to the heating elements 28 and 2| and extinguishing thelamp 32.

Movement ofmovable. contactiltof the circuit breaker 24 into engagementxwith its fixed contact .26 results-in the energization of a synchronous timing motor. The timing motor 401 15 13130- vided with a, pair of timercontacts 4| whichrare normally in their closed position, but which open .at the end I of :a, predetermined curingv cycle as measured by the timer motor 40. The timer contacts 4| are connected in series with the operating coil 42 of a. relay 43 and the seriesconnected contacts 4| and operating coil 42 are connected in parallel with the energizing windings on the timer motor 40. Thus it is obvious that the relay 43 will be operated only during the timing cycle of the motor 40. The relay 43' is provided with apair of normally open contacts 44 connected in series with an indicator lamp 45 across the source 22, and such an arrangement provides an instant indication of the completion of a curing cycle.

In operation, the operator places an article to be vulcanized into the lower mold cavity after which the upper mold section [2 is lowered thereby closing the microswitch l5 and energizing the heating elements 20 and2l, and at the same time lighting the lamp 32 to give the operator visual evidence that the molds are heating. When the molds reach a predetermined temperature, the thermoswitch 3D closes the circuit through the low resistance 3| thereby increasing the current flow through the coil 23 of the circuit breaker 24. The increased current flow is of such magnitude, as determined by the operating conditions of the circuit elements, to cause the movable contact 21 to be moved out of engagement with fixed contact 25 and into engagement with fixed contact 26, thereby extinguishing the lamp 32 and stopping the flow of current to the heating elements 28 and 2 Engagement of contact 21 with contact 26 immediately starts motor 38 on a timing cycle and simultaneously energizes the operating coil 42 of relay 43, thereby closing contacts 44 to light the indicator lamp 45 to give the operator visual evidence that a curing cycle is in progress. When the timer motor times out, its contacts 4| open, thereby deenergizing the operating coil 42 and consequently extinguishing the lamp 45 due to opening of the contacts 44 controlled by the coil 42.

It is to be understood that the accompanying drawings are purely schematic in nature, and the equipment used in actual practice ordinarily includes suitable housings for the parts here described. The shape of the mold cavity may assume any desired form depending upon the article being vulcanized. For example, each of the sections may be provided with a semi-cylindrical cavity of such size as to be capable of advantageous use as a splice vulcanizer for cables. Any convenient means may be employed for closing the sections and securing them in closed position, such, for example, as a handle and toggle mechanism. It will be observed that the circuit breaker 24 acts in a manner similar to a marginal relay and the latter may be employed without departing from the scope of the invention.

It is to be understood that the abovedescribed arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. In Vulcanizing apparatus, a pair of mold sections, electrical resistance heating elements in each mold section, a serially connected thermal responsive switch and resistance combination shunting the heating elements in said sections, said switch being in thermal relationship with one of said sections and adapted to be closed upon attainment of a predetermined heating temperature in said mold sections, a source of current for energizing said elements, a circuit breaker connected in series with said elements and adapted to be released upon lowering of the resistance in the heating circuit due to closure of said thermal responsive switch, a visual indicator in shunt with said elements and adapted to be deenergized by said breaker, an auxiliary contact on said breaker positioned to complete a secondary circuit from said source upon release of said breaker, a synchronous timing motor in said secondary circuit, a relay having its operating coil in parallel with said synchronous motor, a pair of timing contacts controlled by said motor connected in series with said operating coil, 9. set of normally open contacts on said relay, and a visual indicator energizable by closure of said last named contacts, said last named visual indicator being adapted to be deenergized at the end of the timing cycle of said motor through opening of said timer contacts and deenergization of said relay coil.

2. Vulcanizing apparatus comprising in combination, a Vulcanizing chamber, resistance heating elements for heating said chamber, a serially connected thermal responsive switch and resistance combination shunting said elements, said switch being in thermal relationship with said chamber and adapted to be closed upon attainment of a predetermined heating temperature therein, a source of current for energizing said elements, a circuit breaker connected in series with said elements and adapted to be released upon lowering of the resistance in the heating circuit due to closure of said thermal responsive switch, a visual indicator in shunt with said elements and adapted to be deenergized by said breaker, an auxiliary contact on said breaker positioned to complete a secondary circuit from said source upon release of said breaker, a synchronous timing motor in said secondary circuit, a relay having its operating coil in parallel with said synchronous motor, a pair of timing contacts controlled by said motor connected in series with said operating coil, a set of normally open contacts on said relay, and a visual indicator energizable byclosure of said last named contacts, said last named visual indicator being adapted to be deenergized at the end of the timing cycle of said motor through opening of said timer contacts and deenergization of said relay coil.

3. Vulcanizing apparatus comprising means to initiate a heating cycle, visual indicating means energizable throughout said heating cycle, a curing cycle timer, means responsive to attainment of a predetermined temperature in said apparatus to stop said heating cycle and energize said ouring cycle timer, visual indicating means energizable throughout the curing cycle, and means operative at the completion of said curing cycle to deenergize said curing cycle indicating means.

4. Vulcanizing apparatus comprising a vulcanizing chamber, electrical resistance heating means to heat said chamber, a serially connected thermal responsive switch and resistance combination shunting said heating means, said thermal switch being in thermal relation with said chamber and adapted to close upon a predetermined temperature rise therein, a source of cur-- rent for said heating means, a marginal relay connected between said source and heating means, said relay being actuable by a predetermined increase in current flow therethrough caused by closure of said thermal switch. to

break the circuit to said heating means, a set of auxiliary contacts on said relay closable by actuation of the relay, indicating means shunting said heating means, curing cycle timing means associated with said auxiliary contacts and energizable by closure thereof and indicating means energizable throughout the timing cycle of said curing cycle timing means.

5. Vulcanizing apparatus comprising means to initiate a heating cycle in said apparatus, indicating means energizable throughout said heating cycle, a curing cycle timer, a thermoswitch responsive to a predetermined temperature in said apparatus and operative to stop said heating cycle and energize said curing cycle timer, a relay having its operating coil in parallel with said timer, a set of normally closed contacts on said timer in series with said relay operating coil, a curing cycle indicator, and a set of normally open contacts on said relay in with said device, an electrically energized signal energizable coextensive with the energizing peri- 0d of said element, thermo-affected means associated wtih said device and shunting said element operative upon being heated to a predetermined value to complete an auxiliary circuit therethrough of substantially less resistance than the resistance of said element taken alone, an electromagnetic switch having an operating coil eifective in response to a predetermined current therethrough, said switch having normally closed contacts in series with said shunt connected element and thermo means, a source of current for said element connected through said operating coil'and said normally closed contacts, a curing cycle timer, an electrically energized signal energizable coextensive with the timing period oi. said timer, and a set of normally open auxiliary contacts on said switch connected between said source and said timer and closable by virtue of a flow of current through said operating coil of at least said predetermined value.

7. In a vulcanizing apparatus a source of current, a heating element, means to connect said heating element to said source of current including a circuit breaker having its coil in series with said source of current and said heating element, a thermo-responsive switch in parallel with said element for shunting said element to supply a surge of current through the coil of the circuit breaker when said apparatus reaches a predetermined temperature and means under control of the circuit breaker for measuring and indicating a time interval after said predetermined temperature is reached.

8. In a, vulcanizing apparatus, a source of current, a heating element, means to connect said heating element to said source of current including a circuit breaker having its coil in series with said heating element and said current source, a thermo-resp-onsive switch positioned to be actuated in response to a predetermined temperature condition in said apparatus, said thermo-responsive switch being connected in shunt with said element to supply a surge of current through the coil of the circuit breaker when said predetermined temperature is reached, indicating means shunting said element and means under control of the circuit breaker for measuring a time interval after said predetermined temperature is reached.

9. In a vulcanizing apparatus, a source of current, a heating element, a visual indicator shunting said element, means to connect said heating lement and visual indicator to said current source including a marginal relay having its operatin coil in series with said heating element and said current source, a temperature responsive switch in thermal relation with said apparatus, said temperature responsive switch being connected in parallel with said element thereby to supply a surge of current through the operating coil of said marginal relay when said apparatus reaches a predetermined temperature and a timing motor under control of said marginal relay for measuring a curing time interval after said predetermined temperature is reached.

19. In a vulcanizing apparatus, a source of current, a heating element, means to connect said heating element to said current source including a circuit breaker having its coil in series with said heating element and said current source, a relatively low resistance adapted to shunt said heating element, means responsive to a predetermined temperature in said apparatus to render said resistance effective to supply a surge of current through the coil of the circuit breaker, and means including a timing motor and an indicator under control of the circuit breaker for measuring and indicating a time interval after said predetermined temperature is reached.

PETER J. MAMOLA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,412,568 Mortensen Apr. 11, 1922 1,588,287 Willmann June 8, 1926 2,427,444 Colombo Sept. 16, 1947 2,509,693 Morrison May 30, 1950

Images