US2249237A

US2249237A - Electric circuit controller

Info

Publication number: US2249237A
Application number: US306692A
Authority: US
Inventors: Rolland S Fulton
Original assignee: National Time and Signal Corp
Current assignee: National Time and Signal Corp
Priority date: 1939-11-29
Filing date: 1939-11-29
Publication date: 1941-07-15
Anticipated expiration: 1958-07-15

Description

July 15, 1941. R. s. FULTON 2,249,237

ELECTRIC CIRCUIT CONTROLLER Filed Nov. 29, 1939 4 Sheets-Sheet l 1k: 2 11v VENTOR A TTORNEY July 15, 1941. s FULTON 2,249,237

ELECTRIC CIRCUIT CONTROLLER Filed Nov. 29, 1939 4 Shets-Sheet 2 INVENTOR July 15, 1941; R. s. FULTON 2,249,237

ELECTRIC CIRGUIT CONTROLLER Filed Nov. 29, 1939 4 Shee'tSTSheet 3 INVENTOR' E BY . M ATTORNEY July 15, 1941. R. s. FULTON 2,249,237

ELECTRIC CIRCUIT CONTROLLER Filed Nov. 29, 1959'- 4 Sheets-Shqet 4 [NVENTOR Patented July 15, 1941 ELECTRIC CIRCUIT CONTROLLER Rolland S. Fulton, Detroit, Micln, asslgnor to National Time & Signal Corporation, Detroit, Mich., a corporation of Michigan Application November 29, 1939, Serial No. 306,692

8 Claims.

This invention relates to electric circuit controllers and the object of the invention is to provide a rotary timer for controlling electric circuits where it is desired to close and. open different circuits successively, or simultaneously.

One of the particular objects of the invention is to provide a rotary timer utilizing cams and rollers arranged so that the rollers in moving over the cam surfaces will make and break electric circuits in the desired order and provided with means for driving the cams at various speeds to close or open the circuits at desired time intervals.

Another object of the invention is to provide a variable speed gear mechanism consisting of a series of gears spaced along a shaft and a movable gear on the cam drive shaft movable into mesh with the different gears to produce different speeds of rotation of the cam drive shaft.

A further object of the invention is to provide a five speed variable gear train into which a gear on the cam drive shaft is movable, the said gear train being so arranged with the axes-at an angle to the axis of the common gear so that the common gear may be moved through the teeth of the different gears in the gear train to bring any one of the gears into operation to drive the cam shaft at the desired speed.

A further object of the invention is to provide a rotary timer including a series of cams and a series of rocker arms each carrying .a roller riding on the respective cam, one type of rocker arm being arranged to drop to make the circuit and the other type of rocker arm being arranged to drop to break the circuit whereby the lag in movement of the rocker arms is compensated by the same movement of the rocker arms to either make or break the circuit.

Another object of the invention is to provide a rotary timer so arranged that the making and breaking of the circuit may be accurately con trolled as to time interval.

Ihese objects and the several'novel features of the invention are hereinafter more fully described and claimed and the preferred form of construction by which these objects are attained is shown in the accompanying drawings in which" Fig. 1 is a perspective view of a rotary timer designed for controlling welding circuits and embodying my invention.

Fig. 2 is a front elevation thereof.

Fig. 3 is an end view of the timer.

Fig. 4 is a section taken on line 4-4 of Fig. 2.

Fig. 5 is a section taken on line 55 of Fig. 2.

Fig. 6 is a section taken on line 6-5 of Fig. 2.

Fig. 7 is a top plan view of the rotary timer.

Fig. 8 1s a schematic diagram of the circuits to. the different rocker arms.

Fig. 9 is a view of the trip spring switch for closing the secondary circuit at the completion of rotation of one of the cams.

Fig. 10 is a schematic diagram of the circuit which is controlled by the trip spring switch shown in Fig. 9.

The device, as shown in Fig. 1, comprises a casting I having a frame extension 2 provided with an upright end 3 in which one end of the shaft 4 is rotatably mounted. The opposite end of the shaft 4 as shown in Fig. 2 is rotatably mounted in the

plates

5 and 6 which are supported on arms 1 extending from the frame I and shown more particularly in Fig. 7.

The portion of the shaft 4 between the

plates

5 and 6, as shown in Fig. 2, is provided with a key-way 8 and a gear 9 is mounted on the shaft 4 and is provided with a screw I0 in the hub extending into the key-way 8 so that the gear 9 may be moved longitudinally of the shaft between the

plates

5 and 6 and Will rotate with the shaft. Rotatably mounted in the top of the

plates

5 and 5 is a shaft II which extends at a slight angle to the shaft 4 and is provided with a series of pinions I2 secured thereto and each of a different diameter. These five pinions each have a different number of gear teeth but all have the same pitch and the shaft H is set at an angle so that the gear 9 may be moved into engagement with any one of the pinions it of the gear train. This construction is not standard gear engineering practice and required the maleing of a special setof gear cutters which de parted from standard technical text book data to obtain this result. These pinions provide five different speeds at which the cam shaft t may be rotated through the same gear 9. By changing the gear 5 different speed ranges may be covered. On the end of the shaft I I extending beyond the plate 8 is a gear l4 meshing with a pmion shown in Figs. 2 and 'l and a large gear it is sacured to rotate with the gear l5 and meshes with the drive pinion secured to the shaft of an electric motor l8 which is supported on the support arms 5.

Any number of cams may be secured to the cam shaft 4 and the particular form of the device illustrated is for use with a welding machine in which four cams are utilized to close or'open two circuits.

The outer cam I9 .is what is called the on pressure cam and is utilized to close an electric circuit to an electrically operated valve (not here shown) to apply pressure to the welding electrode and is shown more particularly in Fig. 3. The second cam is arranged to close the electric circuit to the welding electrode to provide welding current to the electrode and is shown more particularly in Fig. 4. The cam 2| is designed to open the electric circuit providing welding current to the welding electrode and is shown more particularly in Fig. 5. The last cam 22 is called an oiT pressure" cam and is adapted to open the circuit to the electric valve controlling the pressure on the electrode.

The cams are so designed that, first, pressure is applied to the electrode, next, welding current is applied to the electrode and subsequently the welding current is cut oil and then the pressure on.the electrode is released. While the particular form of the device shown is designed for this purpose, this is only one application of the invention as the electric circuits controlled by the cams may do any one of a number of diilerent operations, The cam I9 is shown more particularly in Fig. 3 and is provided with a high Dortion 23 and with a low portion 24 having a sloping face 25 leading from the low to the high portion and a direct drop 25 from the high portion to the low portion. As shown in Figs. 1, 2 and 7 the frame :1 is provided with a boss 21' from which two

stationary arms

28 and 29 extend. The arm 22 provides a support for the several insulating blocks which turn on the arm 29. The insulating block 3% is provided with an arm 32 of insulating material and on the end of this arm is a bracket 33 carrying a roller 34 which rides on the surface of the cam 29 as shown in Fig. 3.

Mounted on the block 3| is a contact arm 35 to which a wire 38 is connected and this contact arm is arranged to engage a contact 31' mounted in the arm 38 which is formed of insulating material and is also shown in Figs. 2 and 7. This arm is supported in the casting and carries the several contacts which are opened and closed by the cams. The contact 3'! is connected by a wire 39 into a circuit so that current may flow through the wire 35, contact arm 35, contact 3! and through the wire 39 to complete a circuit when the contact arm engages the contact 37 at the time that the roller 34 drops ofi from the high part of the cam onto the low part of the cam. The cam is turnable in a clockwise direction so that as the roller 34 passes over the shoulder 25 the spring 38 will push the roller down onto the low part of the cam and, at the same time, will move the insulating block 3| in a clockwise direction bringing the contact arm 35 into engagement with the contact 31.

The cam 25 is shown more particularly in Fig. 4 and is provided with a high portion 40 and with a shoulder at providing a direct drop onto the low portion 42 of the cam 29. This cam 20 is also provided with an angular portion 43 leading from the low to the high portion of the cam. A shutter 44 is pivotally mounted on the shaft 49 shown in Fig. 4 and may be adjusted on the cam 20 by means of the machine screw 45 and the apertures 46 on the shutter through which the screw may be inserted and threaded into the cam 20. By adjusting this shutter on the cam shaft 4 and securing it in place by the screw 45 the high portion of the cam may be lengthened or shortened as desired and this shutter is provided with an angular face 41 leading from 75 the low to the high portion of the cam when the shutter is in the position shown in Fig. 4.

A roller 48 rides on the periphery of the cam 20 and shutter and is carried in a bracket 48 which is secured to an insulating arm 50 on the insulating block 5|. This insulating block 5| is similar to the block 3| shown in Fig. 3 and carries a contact arm 52 arranged to contact a contact 53 in the insulating bar 3 8, as will be understood from Figs. 4 and 7. A spring 30 is also provided to place downward pressure on the arm 50 so that when the roller drops over the shoulder 4| the arm 52 will make contact with the contact 43. This cam 20 is secured to the cam shaft 4 to rotate in a clockwise direction with the cam l9 and by this arrangement as the shoulders of these cams pass beneath the rollers the rollers will drop so that the contact arms 35 and 52 make contact with the contacts 31 and 53 by dropping movement of the roller.

Fig. 5 shows the double cam formed from the two parts 2| and 54. The cam 2| is provided with a series of high cam portions while the cam 54 is provided with a series of high cam portions 56 which are duplicates of the cam portions'55 of the cam 2|. As will be understood from Fig. 5 these cams may be adjusted on their axes so that the earns 55 and 56 provide longer or shorter high cam portions for the roller 51 and these cams may be adjusted in relation to each other by means of the bolt 58 extending through the slot 59 in the cam portion 54. This cam is designed particularly to provide an interrupted weld which is the latest development and provide a means for rapidly making and breaking the weld current during rotation of the timer cam through 360 degrees or one complete turn. The adjustment of the cam allows the interruption periods to be lengthened or shortened as desired in accordance with the work bemg done. When it is not desired to use the machine for an interrupted weld, the double cam 2| and 54 may be replaced by a cam having continuous high and low portions.

Ihe roller 51 for this cam is supported in a bracket 60 on the insulating arm 6| which is secured to the insulating block 62 rotatably mounted on the shaft or arm 29. Secured to this block 52 is a contact arm 63 arranged to contact a contact 64 inthe insulating arm 38. It will be noted that this contact 84 and arm 63 is reversed in position from the contact 53 and arm 52 shown in Fig. 4. By this arrangement the contact arm 63 is held in contact with the contact 84 when the roller 51 is riding in the high part of the cam shown in Fig. 5 but when this roller drops into the notches in the cam the arm 63 will be turned in a clockwise direction on the axis 29 to break its engagement with the contact 64. It will thus be seen that the roller 48 in Fig. 4 will drop to make the contact while the roller 57 in Fig. 5 will drop to break the contact. This cam arrangement shown in Fig. 5 is called the oil-weld timer cam while the cam arrangement shown in Fig. 4 is known as the on-weld timer cam.

The last cam shown in Fig. 6 is the oil'- pressure cam and is arranged by means of an electric circuit and an electrically operated valve (not here shown) to release the pressure from the welding electrode. This cam 22 is provided with a high portion 65 and with a shoulder 66 providing a direct drop to the low portion 51 of the cam. A roller 68 rides on this cam and is supported on an insulating arm 68 secured to an insulating block 10 and having a contact arm I I arranged to contact the contact 12 mounted in the insulating arm 38. This contact arm II is also arranged so that when the roller 68 drops it will open the circuit by moving the contact arm ll out of contact with the contact I2.

The on-pressure contact arms 35 and 1| are electrically connected together by the wire 36 shown more particularly in Figs. 3 and 7 and the on-weld and on-weld contact arms 52 and 63 are electrically connected together by a wire 13 shown in Fig. 7. As shown in Fig. 2, an arm I4 extends outwardly from the base I and an insulating block 15 is mounted on the end of this arm and carries spring contact arms I6 and TI which are normally in contact as shown in Figs. 3 and 8. The spring contact arm "I6 extends outwardly into the-path of movement of a pin I8 on the cam I9 and this pin may be mounted in the diiferent apertures "I9 in this cam. As the cam revolves in a clockwise direction it will contact the end 80 of the contact arm I6 which opens the circuit momentarily at this point drops an electrically locked-in relay, which opens one side of the line and stops the motor as will be understood from Fig. 8. This trip spring switch is connected by means of contacts to each arm into the motor circuit and is used where it is desired to stop the motor at the completion of one full revolution of the cams.

A set of terminal blocks ill and 82 are mounted on the base member I as shown in Figs. 3 and '7 and these terminal blocks are also shown in Fig. 8.v The electric current supply for the motor is carried over the wires 83 and 84 from 115 volt AC supply and these wires are connected to the terminals 85 and 35. The terminal 86 is connected to a terminal Bl by the'wire 88 and this terminal 8i is connected through a switch 89 to the terminal 90 so that these

terminals

81 and 90 may be electrically connected by closing the switch button 89. The terminal 90 is connected by means of a wire 9! to the electric motor I8 shown diagrammatically in Fig. 8 and the terminal 8G is connected by means of a Wire 92 to the opposite side of this motor.

The terminal 86 is connected'by means of a wire 93 to the switch arm ll shown in Figs. 3

and 8 and the switch arm I6 is connected by means of the wire 94 to a relay switch 95 of which the coil 58 is connected across the wires 9| and as shown in Fig. 8. The terminal block ill is provided with terminals 9i and 98 which are connected by means of wires 99 and 800 to the electrodes of a welding machine (not here shown) and the terminals NH and E02 are connected by wires I03 and I04 to an electrically operated pressure valve (not here shown) for applying pressure to the Welding electrode. The wire I leads from the terminal 91 to the contact 04 shown in Figs. 3 and 8 which is the offweld contact. The wire I06 is connected to the terminal 98 and leads to the contact 53 which is the on-weld contact and is shown in Fig. 4%. A wire I01 leads from the terminal Elli to the contact 72 which is the off pressure contact and is shown in Fig. 6. The wire I08 is connected to the terminal I02 and leads to the contact 31 which is the on-pressure contact and is shown in Fig. 3.

The trip spring switch shown in Figs. 9 and is the reverse of that shown in Figs. 3 and 8 and is shown as an alternative form and is so arranged that the pin I8 will engage the trip springarm I09 and momentarily close the circuit to actuate a relay circuit shown in Fig. 1Q to break the motor circuit thus stopping the cam after one complete revolution. However, as the trip pin will tend to carry past the endof the trip spring switch arm I09 due to the ar reduction this switch automatically re-setsitself so that upon subsequent closing the starting button 89 shown in Fig. 8 the motor may be started for another complete revolution. In fact, the switch 89 shown in Fig. 8 may be utilized to start the revolution of the cams by the motor with either circuit shown in Figs. 8 or 10.

The series of pinions shown in Fig. 2 drive a gear 9 to rotate the cam shaft 4. The pinions shown may be arranged through the use of the 'gear 9 meshing with the teeth of the different pinions to rotate the shaft 4 from forty-two to eighty revolutions per minute. To increase the revolutions a diiferent gear 9 may be substituted to give a speed of rotation from ninety to one hundred fifty revolutions per minute while by substitution of another gear 9 a speed of one hundred twenty to two hundred revolutions per minute may be obtained. This of course, is a matter of design depending upon the time intervals in making or breaking contacts that it is desired to produce. Assuming the gears to be set to turn the shaft 4 at a speed of sixty revolutions per minute this would mean that each cam is rotating at one revolution per second and by I dividingthe circumference of the respective cam carefully any part of a second of make contact or break contact may be produced. Also, by sub stituting different gears for the gear 9 different speeds may be attained to further increase the speed or time interval of the make or break contact. It is when the time interval for the make and break contacts to be made is a small fraction of a second that the importance of the rollers dropping both to make or break the contacts becomes important, becaus? it is then absolutely essential that the lag or delay in movements of the rollers be at the same interval during the break contact as during the make contact so that the interval of electric current flow may be accurately controlled.

To operate a single circuit it is only necessary to use two cams rather than the four shown, as the four shown, as hereinbefore described, will operate a pressure control circuit as well as the welding electrode circuit and the device may be used with a welder in which the operator applies the pressure manually and it is only necessary to equip the machine with on-weld and off weld cams. While I have described the device as utilized in connection with a welding machine it is designed for use wherever it is necessary to provide timed electrical operations either where it is necessary to make a single contact and maintain it for a certain time interval or to maintain a movement of contacts of predetermined intervals spaced over a certain time interval.

From the foregoing description it becomes evident that the device is very eflicient in operation, provides an accurate and exact means for controlling the time interval of an electric circuit, allows the device to be set to produce any combination of circuit intervals and provides a device which accomplishes the objects described.

Having thus fully described my invention, its utility and mode of operation, what I claim-and desire to secure by Letters Patent of the United shaft, a series of cams mounted to rotate with the cam shaft, 9. series of rocker arms pivotally mounted adjacent the cams, a roller supported in the outer end of each rocker arm and riding on one of the cams, each cam being provided with high and low portions and a contact arm on each rocker arm movable into and out of engagement with a contact, the arrangement providing that one of the contact arms is movable into engagement with its contact when the roller drops onto the low portion of its cam and another of the contact arms is movable out of e gagement with its contact when the roller drops to the low portion of its cam, the two contact arms being connected into a single series circuit whereby the time interval of the dropping of one roller from its high point to the low point offsets the time interval required for the other roller to drop from its high point to its low point on the cam.

2'. In an electric circuit controller having a cam shaft, a series of cams mounted to rotate with the cam shaft, a series of rocker arms pivotally mounted adjacent the cams, a roller supported in the outer end of each rocker arm and riding on the respective cam, each cam being provided with a high and a low portion, a contact arm on each rocker arm movable into and out of engagement with a contact of an electric circuit, the parts being so arranged that one of the contact arms is movable into engagement with its contact when the roller drops onto the low portion of its cam and another of the contact arms is movable out of engagement with its contact when the roller drops onto the low portion of its cam, the pair of dissimilar contact arms being connected into a single series circuit wherein both contacts must be closed to permit a flow of current in the circuit, the arrangement providing that, when one contact arm drops to close its portion of circuit the other contact arm drops to open its portion of circuit, the respective cams being adjustable by rotating of one or the other said cams on the cam shaft to vary the spacing between the drop off portions thereof.

3. In an electric circuit controller having a cam shaft, a series of cams mounted to rotate with the cam shaft, a roller riding on the periphery of each cam, a rocker arm supporting each roller, a contact arm carried by each rocker arm, a stationary contact for each contact arm, the parts being arranged with some of the contact arms being in engagement with their contacts when the respective roller is on the high part of its cam and some of the contact arms being in engagement with their respective contacts when the respective roller is on the low part of its cam, the contacts being connected in circuits so that one of each type of contact arm is connected into each circuit in series, to provide identical movement of contact arms in one direction to alternately make and break said circuit as the roller of each contact arm drops off its respective cam step, to sequentially make and break .the circuit.

4. In an electric circuit controller having a shaft, a series of cams arranged in pairs on the shaft and each having a high and a low portion and a step therebetween, a roller riding on each cam, a rocker arm supporting each roller, each rocker arm being provided with a contact arm, the parts being so arranged that one of the arms is arranged to make contact when its roller drops off its cam step and the other arranged to break contact when its roller drops off its cam step, said contact arms being connected in pairs in a single series circuit, and actuated by respective 7 pairs of cams on said shaft, whereby one contact arm always closes the circuit, and the other contact arm always opens the circuit, said cam pairs being rotatively positionable on the shaft to vary the "on" period of circuit with respect to its total rotating time cycle, or with respect to other circuits controlled by other similar means on said cam shaft and means for driving the cam shaft including a series of pinions and a common gear movable into mesh with any one of the plnions to vary the speed of rotation of the cam shaft.

5. In an electric circuit controller, a cam shaft, 8. pair of cams secured to the cam shaft, a roller riding on each cam, a rocker arm supporting each roller, a contact carried by each rocker arm, one contact being arranged so that when its roller drops the rocker arm contact will close the circuit and the other contact arm being arranged so that when its roller drops the rocker arm contact will open the circuit, said pair of contact arms being connected into one single series circuit wherein both contacts must be closed to complete the circuit, the circumferences of the two cams being of a form to provide accurate intervals during which the rollers drop, means for driving the cam shaft at various speeds, and

-means for rotatively adjusting the cams on the cam shaft to vary the time period of interruption of the circuit.

6. In an electric circuit controller, a cam shaft, a series of cams arranged in pairs on the cam shaft to rotate therewith, a series of rocker arms, one pivotally mounted adjacent each cam, a roller carried by each rocker arm each riding the companion cam of the pair, each cam of the series being provided with a high and a low portion, a contact arm on each rocker arm, a stationary contact of an electric circuit for each contact arm, one of the contact arms being movable into engagement with its contact when the companion roller drops onto the low portion of its cam, and another of the contact arms being movable out of engagement with its contact when its roller drops onto the low portion of its cam, the contact arms for each pair of cams being connected in the circuit and the circuit requiring both contacts to be closed to permit flow of current therein, the cams, rollers and contact arms being so arranged that'one contact arm drops onto the low portion of its cam to close the respective contacts, and the other contact arm drops onto the low portion of its cam to separate the respective contacts, means for adjusting the companion pair of cams rotatively on the cam shaft to thereby vary the position of the low portion on one cam rotatably of the cam shaft in respect to the low portion of the companion cam and thereby vary the period of closing of the electric circuit.

7. In an electric circuit controller, a cam shaft, a series of cams each having a high and a low por tion mounted to rotate with the cam shaft, a roller riding on the said portions of each cam consecutively, a rocker arm supporting each ro1ler, a contact arm carried by each rocker arm, a contact of an electric circuit for each contact arm, some of the contact arms being in engagement with their contacts when the respective roller is on the high part of its cam and some of the contact arms being in engagement with their respective contacts when the respective roller is on the low part of its cam, the contacts being connected in electric circuits so that one of each type of contact arm is connected into each circuit in series to provide identical movement of the contact arms in one direction to alternately make and break said circuit as the roller oi each contact arm drops onto the low portion of its respective cam to make and breakthe respective circuit.

8. In a controller for a pair of electrical circuits, a cam shaft, a pair of cams for each cir' cuit mounted on the cam shaft, means for driving the cam shait, including an electric motor, and a series orvariabie reduction gears, means controlled by each pair of cams for making and 1