US2204513A

US2204513A - Safety control for vulcanizer presses

Info

Publication number: US2204513A
Application number: US144821A
Authority: US
Inventors: Rolf A F Sandberg; Paul F K Erbguth; Jr Ed S Smith
Original assignee: CHARLES TAGLIABUE Manufacturing CO
Current assignee: CHARLES J TAGLIABUE Manufacturing Co; CHARLES TAGLIABUE Manufacturing CO
Priority date: 1937-05-26
Filing date: 1937-05-26
Publication date: 1940-06-11
Anticipated expiration: 1957-06-11

Description

J 11, 1940- R. F. SANDBERG El AL 2,204,513

SAFETY CONTROL FOR VULCANIZER PRESSES Filed May 26, 1957 //v VEN T0 Rs.- RAF. SANDBER G, EEK. ERBGUTH.

E8 SMITH JR. BY 4 TTORNE VJ Patented June 11, 1940 UNITED STATES PATENT OFFICE SAFETY CONTROL FOR VULCANIZER PRESSES York Application May 26, 1937, Serial No. 144,821

Claims.

This invention relates to timers for safely controlling the cycle of operation of individual vulcanizer presses for hollow tires. It particularly relates to arrangements wherein one such timer -5 controls the operation of two or more such presses.

A particular object of the present invention is to provide a controlling system with safety interlocks functioning to give a reliability of opera '10 tion and assurance of safety to the operator hitherto unobtainable in this art. While others have controlled only the exhaust from the interior of the tires, we also positively block the entrance of either steam or hot water to the in- 15,1et line to the interior of the tires and simultaneously connect the same to a drain.

As regards safety of operation, it is axiomatic that a control system must be safe both when automatically and when manually operated. 'We

attain this end, not by a mere aggregation of old elements and instrumentalities, but by so modifying the arrangement and organization of our apparatus as to provide greater safety by a new combination.

We also use a permissive running arrangement in which the timer is manually started and runs uninterruptedly through its cycle if the pressure in the exhaust line is above a predetermined minimum at a time near the beginning of the cycle after the presses are closed, so that the timer will not continue to operate unless a tire is in each press.

These and other objects of our invention will appear to those skilled in the art from the ac-' ,u companying drawing and specification, in which is illustrated and described a specific embodiment of our invention. It is our intention to claim all that we have disclosed that is new and useful.

The drawing shows the electrical, pneumatic 40 and hydraulic circuits and their associated operative members, including a cam for a timer governing two presses, for the preferred embodiment of our improved safety method utilizing the permissive starting arrangement in connection with two push-buttons.

The description of the equipment and its operation is in the order of the following resume:

A. General description; and

B. Detailed description of the preferred illustrated embodiment of our invention.

Throughout the description, it must be remembered that there are three conditions of operation; (1) normal, (2) manual, and (3) for week- ;5 ends, or other protracted periods of plant inactivity, during which the presses are closed and W the molds kept heated but do not contain tires.

A. General description Before proceeding with the detailed description for a typical cure, it is believed hel ful to give the following brief general description to make clear the functioning of the various operating parts.

Fig. 1 is a diagrammatic view of the controlling v 0 system, showing the timer in front elevation. Fig. 2 is a side elevation, partially in section, of a detail of the timer viewed from the left-hand side in Fig. 1. In the figures, each individual tire mold press is hydraulically actuated by a piston governed by a reversing valve which is air-operated by a spring-opposed diaphragm. After both presses are closed, steam is admitted to the interior of each hollow tire on one side and steam is simultaneously exhausted to a drain from its other side by valves which are likewise air-operated by spring-opposed diaphragms. After the air is blown out, the steam is shut off and hot water under pressure of several hundred lbs. per sq. in. is circulated through the tire and 5 returned by a 3-way exhaust valve to the circulating system instead of to a drain. The timer controls, by a single cam, the sequential operation of the air-valves for the several diaphragms. This cam positions a single controlling member that operates these air-valves to give the desired sequence of operations according to flue various displacements of this member. The cam. is rotated by a self-starting synchronous motor precisely geared to make exactly one revolution for one complete cycle of operation take the desired time.

With the timer shown, the attendant starts the timer by simultaneously pressing two push-buttons, causing the cam to run steadily forward so 40 that each press closes, after which steam is admitted to the interior of the tire. The running switch of the timer is so arranged that the timer will stop unless the pressure in the exhaust has risen after a predetermined interval following the manual starting of the timer, failure to rise ordinarily being due to the absence of a tire from either press or failure of either of the molds to close. However, in the normal operation of this timer, it will run continuously throughout the cycle. While this permissive feature is similar in some respects to that shown in the Bast et a1. Patent No. 1,959,336, we have applied the teachings thereof, which are for a pot heater containing a number of tires,'in a novel manner valve, having a weaker spring to the individual mold presses which face a different problem; that of safely operating such presses, a result which we attain with our improved system.

The steam cannot be introduced until after each press has been closed. If, for any reason, the timer stops, this is indicated by the running light on top of the timer. As long as the press is closed, steam and hot water may be admitted to the interior of the tire, and the exhaust line is connected either to drain or to circulate. Whenever air pressure does not reach the diaphragm of the hydraulic reversing valve, it is held in its press-closing position by the diaphragm-opposing spring. Consequently, failure of the air-supply cannot cause the press to open. At the end of the cure, the timer shuts off the flow of hot water, admits steam to blow out the hot water to the exhaust, and then stops the flow of steam, leaving the exhaust open. The timer then closes a 3-way block valve in the inlet line to the tire, simultaneously opening such line to the atmosphere, and, after a safe interval, operates the hydraulic reversing valve; the block than the hydraulic reversing valve, will close at a lower air pressure, and the hydraulic reversing valve is additionally provided with a capacity-tank and a checkshunted resistance in series therewith to delay the opening, but not the closing, of each press. Each press opens after a predetermined interval following the closure of both steam and hot water supply valves and the opening of the exhaust valve to drain.

B. Detailed description In the drawing, a single timer l0 controls a pair of individual tire vulcanizing presses each press having a movable mold l2 operable by hydraulic piston l3 in its cylinder I4. The opening and closing ends of hydraulic cylinder M are connected with hydraulic reversing valve if: by the opening and closing lines l6 and I1 respectively. Hydraulic pressure supply line If! is connected to the hydraulic reversing valve as is its exhaust hydraulic line I9. Hydraulic reversing valve |5 is positioned by air-operated diaphragm 2|) opposed by a strong spring 2|. A 3-way block valve 3'! is likewise positioned by air-operated diaphragm 38 of the same size as diaphragm and opposed by a weaker spring 39, the arrangement being such that valve 31 well have moved to completely block the fluids entering the supply line 35 and connect the same to atmosphere before reversing valve i5 is moved at all from its press-closing position. Steam supply valve 22 is likewise positioned by its air-operated diaphragm 23 opposed by spring 24, this valve being of the spring-closed type as is also hot water supply valve 25 with its airoperated diaphragm 26 opposed by spring 21. Exhaust valve 28 is air-operated by its diaphragm 2S opposed by spring 30; This valve is of the 3-way type for selectively connecting the exhaust with drain 3| or circulating line 32, which is connected back to the inlet of hot water valve 25, the exhaust line 33 from the interior of the tires being connected therewith at 34. Inlet line 35 is connected with the interior of each tire at inlet connection 36, to connect steam and hot water valves 22 and 25 through block valve 31 with the interior of the tires.

In timer l0, an electric motor of the selfstarting synchronous type drives changeable gears 4| and 42, and shaft 43, to which disc cam 44 is attached normal to the axis of shaft 43. Cylinder hub 45 of the cam has braking ball 46 movable vertically in a fixed groove 4'! so that the cam can turn freely only in a forward direction, i. e., clockwise in the figure. The periphery of cam 44 is made up of circular portions of different radii corresponding with the desired operations. Air nozzle 48 has ball 49 attached thereto to act as a sled-runner and thus space the end of air nozzle 48 just clear of the front surface of the cam so that it cannot hinder the motion thereof. Air-supply line 50 contains cock 5|, normally open but shown closed by its handle 5| in the drawing. Bellows 52, connected to air-supply line 50 is fixed at its upper end, the lower end being free to expand downwardly with an increase of air-pressure therein. Feed resistance 53 is located in the air-supply line just upstream of the bellows. Flexible air-line 54 connects the interior of bellows 52 with nozzle 43, which nozzle is attached to the lefthand end of lever 55, which is pivotally connected by pin 56 to the frame ll! of timer l0 and to the depending portion 51 of bellows 52 by pin 58 attached thereto so that the motion of the bellows results in a corresponding magnified motion of nozzle 48. Roller 59 is rotatably mounted on pin 60 also attached to the lower end of depending portion 51 of bellows 52. Control lever 8| is pivotally mounted at its lefthand end on pin 62 which is attached to timer frame H), the righthand end being biased upwardly by tension spring 53, the upper end of which is likewise attached to timer frame I to the bottom portion of bellows 52 presses against the upper edge of control lever 6| to position it according to the then effective edge of cam 44. Bumps on the lower edge of control lever 6| coactingly abut air-

valves

64, 65 and 66 respectively for operating the reversing valve l5 for the presses, steam valve 22 and hot water valve 25. Adjustable bumper head 61, having sliding pin 68 biased downwardly by spring 59,

Roller 59 attached is provided for each of the air-valves so that the lower end of sliding pin 68 may abut the corre-' sponding stem 10 of each of air-valves S4, 65 and 68. Each air-valve is connected with airsupply line 50 downstream of cock 5|. Airvalve 66 is connected by line TI to diaphragms,

2E and 29 respectively of hot water valve 25 and exhaust valve 23, air-valve 66 being of the reverse-acting type so that line II is normally disconnected thereby from air-supply line 50 and, when stem 10 of air-valve 66 is depressed, the air-pressure reaches line H from air-supply 50. Line 12 connects air-valve 65 with diaphragm 23 of steam valve 22. This air-line 12 contains reverse-acting air-valves 13 which are closed except when movable molds |2 of presses H are closed, at which time these air-valves "l3 connect control air-valve 65 with diaphragm 23. Line 14 connects air-valve 64 with diaphragm 23 of hydraulic reversing valve l5. This line is also connected with the diaphragm 38 of block valve 31, as before mentioned. Line M also contains capacity tank H with series-resistance 18 and check valve 19 shunted around resistance 18 so that each press closes quickly and promptly, but opens slowly and in a delayed manner.

To operate electrical motor 40 of timer l0, an electrical system is provided as follows: blade 80 is biased downwardly by its own elasticity so that its end portion may abut stud-cam 8| on the face of cam 44. Running blade 83 is connected to one line 82 of the current supply. Blade 80 opens the same from blade 81.

from running-blade 83 when stud-cam 8| raises the end of blade 88. Blade 88 is connected by wire 84 with the lower terminal 85 of coil 88 of motor 48. The running of motor 48 turns cam 44 so that its stud-cam 8|" raises blade 88' to close against starting blade 81, which is connected by wire 88 containing two push-buttons 89 (giving two-hand safety starting), with wire 84 which is connected with lower terminal 85 of motorcoil 88, this wire 88 also contains an additional switch means and a relay holding-coil, as will be described later. The upper terminal 98 of coil 86, which is shunted through neon-light 9|, is connected with wire 92 which, like 82, is connected with the current supply source.

Stud-cam 8|" is so located relative to blade "88' of a separate starting switch, the fixed blade of which is blade 81, that starting-switch blades 88-8'| close shortly before running-switch blades: 88-83 are separated at the end of a cycle as in Fig. 1. Stud-cam 8| is of such a length and so located relative to stud-cam 8| that studcam 8| will not only have closed blades 88'-8'| before blades 88-83 open at the end of a cycle but will cause blades 88'-81 to separate before cam 8| brings blades 88-83 to again contact being operated by armature H5 and its holding coi-l I I4. From the foregoing and the figure, it is clear that the arrangement is such that a momentary simultaneous pushing of the two button switches 89 is effective to start the cycle of operation only while stud-cam 8| forces blade 88' against blade 81, in other words at the beginning of a cycle to start the same. In any event, the attendant can tell from running-light 9| whether or not the timer has started upon its cycle of operation.

Motor 48 then operates the timer until cam 8 I rides out from under blade 88' to disconnect The motor then continues to run only if switch blades -96 and 98-99 are closed respectively by stud-cam 94 and bellows |8| which is connected with exhaust line 33 by tubing I82, which closure occurs in normal operation. If, however, the pressure in exhaust line 33 is not sufiiciently high to close contacts 98-99 before blade 88 runs off of cam 8| (relatively speaking), armature H5 will drop so that motor 48 will stop. When the pressure 'in exhaust line 33 subsequently rises enough to cause bellows I 8| to close contacts 98-99, this will not cause motor 48 to run since resistance I I8 in series with coil I II is so high that the pull of coil III on armature I I5 is not sufficient to raise the'same although adequate for holding it once it has been raised. (In other words, this is a permissive system of operating a timer for individual presses.) After the timer has thus stopped due to the failure of steam under pressure to reach exhaust line 33 at the proper mo- -ment, it is necessary for the attendant to manuthe source of trouble before manually closing the switch. Experience has shown that the cure is ordinarily not sufficiently advanced to spoil the tire at this time.

It is evident that a momentary simultaneous push of the two button switches 89 will sufiice to positively cause motor 48 to continue to run long enough to drive stud-cam 8| clear of blade 88 thus bringing cam 44 to a position where the presses close and, upon such closure, steam is supplied to the tires. Once cam 8| has moved clear of the end of blade 88 so that blade 88 contacts blade 83, this contact closes the running circuit of motor 48 and in effect disconnects the starting circuit 88, including switches 89, and the permissive circuit, including switch blades 95-98 and 98-99 until the next cycle of operation subsequent to the manual and simultaneous closing of both switches 89.

As earlier noted briefly, the handle of cock 5| is provided with insulated spur portion 5| for opening blade 15 from blade 16 of a switch in line 88 in series with the two button starting switches 89, the arrangement being such that in shutting off the air-supply from line 58 by cook 51, insulated portion 5| opens the switch so that motor 48 of the timer cannot be started as long as the air-supply is shut off.

Upper end I88 of bellows MI is movable, its interior being connected, as earlier mentioned, by pressure pipe I82 with the exhaust line so that the presence of any inflating fluid, e. g., steam or hot water, in exhaust line 33 causes bellows end I88 to rise to a position corresponding with the then pressure of the exhaust, bellows end I88 then closes blades 98-99 to cause motor 48 to start, assuming that blades 95-96 are then closed by stud-cam 94.

We do not wish to be restricted to air-operatheir valve-operating means. The systems that we have taught would function equally as well 40 with, e. g., electrical operation. Also, with electrical operation we may use a limit switch for the block valve so that the press-reversing valve cannot be opened until after the block valve is in blocking relation to the supply line and connects;

has been brought to a fluid-supply blocking position. We will not burden this specification further by discussing other useful modifications of the disclosures herein, such as will be evident to anyone skilled in this art.

The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described and portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

We claim:

1. In an apparatus including a press for heatprocessing a hollow article, the combination with means for governing the closing and opening of the press, and means for controlling the supply of an inflating fluid under pressure to such hollow article and the exhaustingof such fluid therefrom: of means operatively connected with said press-governing means and connected in series with said fluid-supply controlling means and constructed and arranged to positively block the 75 supply to the interior of the hollow article before said press opening means can act.

2. In an apparatus including a press for heatprocessing a hollow article, the combination with means for governing the closing and opening of the press, means for controlling the supply of an inflating fluid under pressure to such hollow article and the exhausting of such fluid therefrom: of means operatively connected with said pressgoverning means and connected in series with said fluid-supply controlling means and constructed and arranged to positively block the supply to the interior of the hollow article and to connect said interior to exhaust before such press opening means can act.

3. In an apparatus including a press for heatprocessing a hollow article, the combination with a control member, a plurality of pilot means operated thereby, a plurality of servomotor means respectively governed by said pilot means, means operatively associated with one of said servomotor means for controlling the opening and closing of. the press, means operatively associated with one of said servomotor means for controlling the supply of an inflating fluid under pressure to such hollow article and the exhausting of said fluid therefrom, both of said controlling means being operated by its associated said servomotor means, and piping connecting said fluid controlling means with the interior of such hollow article: of means operatively connected to and governed by the pilot means for the presscontrolling means and connected in said piping between said fluid-supplying means and said article and arranged to positively block the supply to the interior of the hollow article and to connect said interior to exhaust before said pressopening means can act.

4. In a cyclically operated apparatus including a press for heat-processing a hollow article, the combination with a timer, means for governing the closing and opening of the press, and means for controlling the supplying of an inflating fluid under pressure to such hollow article and the exhausting of such fluid therefrom, the sequential actuation of said means being governed by said timer: of means operatively connected with the press-governing means and connected in series with said fluid-supplying means and constructed to positively block the supply to the interior of the hollow article and to connect said interior to exhaust before said press-governing means can act.

a. In a cyclically operable apparatus including a press for heat-treating hollow articles, a timer including a time-operated cam, a control member positionable by said cam, a plurality of pilot means operated by said member, a plurality of servomotor means sequentially governed by said pilot means, means for controlling the operation of the press, means for controlling the supply of an inflating fluid under pressure to such hollow articles and the exhausting of said fluid therefrom, each of said controlling means being actuated respectively by an associated one of said servomotor means, and piping connecting said fluid controlling means with the interior of such hollow articles, means actuated by one of the servomotor means operatively connected with the pilot means governing said press, said lastnamed means being connected in said piping between said fluid-supplying means and said article and arranged to positively block the supply to the interior of the hollow article and to connect said interior to drain before said pressopening means can act.

6. The combination set forth in claim 3, in which said servomotor means are pneumaticallyoperated, and the last named means include a delaying means having a resistance and a shunting check-valve therefor operatively connecting the press controlling means and the last named means so that the check-valve is effective only upon a press-opening movement of the pilot means for governing the opening and closing of the press.

'7. In a timer system for one or more presses each for vulcanizing a hollow article, the combination of a timer including a cam, an electric motor for driving said cam at constant speed, and a controlling member positioned by said cam; a plurality of means controlled by said member comprising means for governing the operation of the press, means for supplying an inflating fluid under pressure to the interior of the hollow article, and means operatively connected in series with the fluid supplying means and constructed and arranged to block the fluid supply to the interior of the hollow article and to connect such interior to exhaust before the press operating means can act to cause the opening of the press; switch means, including a manually-operable starting portion and a cam-operable portion connected to said motor and adapted to cause the latter to advance said cam to a position beyond a press-closing position and a predetermined distance beyond a fluid-supplying position subsequent to said press closing position; a running switch connected to said motor and operated by said cam from a position thereof at a predetermined distance beyond said first named position to that for the end of a cycle, thus leaving a gap in the running of the timer; and means including a pressure operated switch having a pressure sensitive portion connectable to the interior of a hollow article in each press and a portion connectable by said cam to said motor and operable to cause the continued running of the latter in the gap between the first named and the last named position only if during suchgap each press contains a hollow article filled with the inflating fluid under at least a predetermined pressure.

8. The combination set forth in claim 7, in

which the first named means includes a pilot operated by said member and the means for supplying inflating fluid to the interior of each hollow article is servooperated by said pilot, and

including an auxiliary pilot on each press connected in series with said first named pilot and operable to supply such fluid only upon the operation of said member and the closure of all of said presses, whereby said pressure operated switch continues the running of the motor-driven cam through the gap only if each press was closed and contained a hollow article filled with the inflating fluid under at least the predetermined pressure at the first named position of the cam.

9. In a timer system for a press for heatprocessing a hollow article, the combination of a timer including a cam and a pilot actuated thereby, a controlling servooperable member biased toward a safe position and normally governed by said pilot, an electric motor for driving said cam at constant speed relative to said pilot, and a plurality of pilots actuated by said member, each of said pilots being normally connected to a common source of power; and a plurality of servooperable means each biased toward a safe (ill position and normally governable by one of the member-actuated pilots comprising means for governing the operation of the press, means for supplying an inflating fluid under pressure to the interior of the hollow article, and means operatively connected in series with the fluid supplying meansand constructed and arranged to block the fluid supply to the interior of the hollow article and to connect such interior to exhaust before the press operating means can act to cause the opening of the press; whereby, upon the interruption of the power supply, the controlling member assumes the stated safe position and thus prevents the further supply of inflating fluid until after the last named means is in its exhausting position and the press is closed.

10. The combination set forth in claim 9 including switch means, having a manually operable starting portion and a cam operable portion, connected to said motor and adapted to cause the latter to advance said cam to a position beyond a press closing position and a predetermined distance beyond a fluid supplying 1 position subsequent to the attainment of said press closing position; a running switch connected to said motor and operated by said'cam from a position thereof at a predetermined distance beyond said first named position to that for the end of a cycle, thus leaving a gap in the running of the timer; and means including a pressure operated switch having a pressure sensitive portion connectable to the interior of a hollow article in each press and a portion connectable by said cam to said motor and operable to cause the continued running of the latter in the gap between the first named and the last named position only if during such gap each press contains a hollow article filled with the inflating fluid under. at least a predetermined pressure.

ROLF A. F. SANDBERG.

PAUL F. K. ERBGUTH.

ED S. SlVHTH, JR.

CERTIFICATE OF CORRECTION.

June 11, 191m.-

Patent No. 2,20h,5'15.

ROLF A. F. SANDBERG, ET AL.

It is hereby certified that error appears in the above numbered patent requiring correction as follows: Strike out the drawing and insert instead the following June 11, 1940- v R. A. F. SANDBERG El Au SAFETY CONTRQL FOR VULCANIZER 1 835525 Filed may 26, 1937 T e S G (U 2 U mama. E m W5 U N.

m Ed mm 0 9 V n o c A 1 v F 1 AM REE HOTR'ATER and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of August, A. D, 19140.

Henry Van Arsdale,

Acting Commissioner of .Patents.

(Seal)