US3586873A - Electric timer - Google Patents

Abstract

An electrical appliance timer having a vibratory ratchet drive coupled to a solenoid-operated armature.

Description

United States Patent Carmen P. Cairelli Flrmington, Conn.

Dec. 6, 1967 June 22, 1971 Dynamics Corporation of America New York, N.Y.

lnventor Appl. No. Filed Patented Assignee ELECTRIC TIMER 3 Claims, 7 Drawing Figs.

U.S.Cl. 307/141, 317/156 1nt.Cl 1101b 7/00 Field of Search 200/38 A;

References Cited UNITED STATES PATENTS Estes Harris... Richtmyer et al. Jacobs Reifel Rowell Primary ExaminerRob ert K. Schaefer Assistant Examiner-H. J. Hohauser Attorney-Richard P. Schulze 307/141 307/141 X 58/23X 307/141 307/132X 317/141 X ABSTRACT: An electrical appliance timer having a vibratory ratchet drive coupled to a solenoid-operated armature.

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SHEET 3 BF 3 CARMEN P CAIRELLI ELECTRIC TIMER This application relates generally to an electric timer and more specifically to a timer which is usable with a standard commercially available power supply.

The use of timing devices for supplying electrical current to loads such as electric motors and the like is well known and in great use today. However, most of the operative devices in use today include a spring-wound timer which is used in conjunction with the electrical device. In this type of timer the mechanism is set in accordance with a spring mechanism and operates to the set degree and ultimately closes an electrical contact leading to the device to be used.

One of the inherent problems of the spring-wound timer is lack of accuracy due to the fact that all springs are not alike and the progressive function of the device varies due to the particular tension varying in the spring itself. When a timer is used which operates over a rather lengthy time period such variation may not be too critical. However, when a timer device is used with any piece of equipment such as an electric blender wherein the time of operation is a matter of seconds, exact measurements become critical due to the particular usage of the device.

Accordingly, it is an object of this invention to provide a compact reliable timer for use in electrical devices.

A further object of the invention is to provide an electrical interlock between the timer and the particular closing mechanism of the device to be used.

These and other objects of the invention will become apparent from the following description when taken in conjunction with the drawings wherein:

FIG. 1 is a plan view of the basic timer mechanism and associated switching elements;

FIG. 2 is an exploded view of part of the basic gearing and cam structure of FIG. 1; I

FIG. 3a, 3b and 3c are basic illustrations of the operating mechanism of the timer of the present invention;

FIG. 4 is a schematic of the basic electrical circuitry involved in the present invention; and M FIG. 5 is a partial view of a modification of the operating mechanism of FIG. 1.

Briefly, the invention consists of a vibratory ratchet drive which is coupled to a solenoid-operated armature. The armature is so designed that it operates once for each half-cycle for the standard 60-cycle operating current, and an associated gear train provides the equivalent timing for operation of a cam wheel which opens or closes an electrical switch to the device to be operated.

Referring now more specifically to the drawings, there is shown in FIGS. 1 and 2 a base 11 on which is mounted a coil 13 which receives current from a standard electrical supply (not shown). Within the coil 13 there is a core structure 15 which in effect provides a standard solenoid construction. The coil 13 and core structure 15 are supported by means of a frame 17 which is mounted on the base 11.

An armature 19 is biased in an upward position by means of an armature return spring 21. The armature is secured to the core structure 15 by means of a screw 23 which is adjustable so as to provide a variance for the desired airgap in the solenoid and armature structure.

For the present illustrated purposes, it is desired that the armature be actuated at each half-cycle of the energizing alternating current so that with a standard commercial supply the armature could be activated at 60 cycles per second. This can be accomplished through the use of a diode as shown in the schematic in FIG. 4 or through the use of a ceramic magnet 25 in series with the magnetic circuit of the electromagnet. With this arrangement, when the coil 13 is excited by the alternating current, the resulting flux will be alternately additive and subtractive with the magnetic flux of the permanent magnet and the net flux will be zero at one-half of the cycle and will approach a double value at the other half of the cycle. In either case, the armature actuation is determined by the fixed frequency input of the alternating current. Accordingly, the mechanical movement of the timer will be in equally timed incremental steps. A detailed explanation of the operational characteristics of such a device may be found in my copending application entitled Half Wave Vibrator Ser. No. 688,419, filed Dec. 6,1967.

In order to provide the necessary mechanical movement, a ratchet spring 27 is shown secured to the armature 19 by means such as a rivet 29. Spring 27 is associated with and turns ratchet 31 with each particular. armature movement. As will be explained in greater detail as the description proceeds, there is also provided a spring member 33 which prevents the ratchet 31 from backing in the counterclockwise direction.

Any gear arrangement may be provided so as to obtain the desired ultimate movement for operating the final switching device. In the present illustration, this gear train is illustrated as gear 35, driven by ratchet 31, which drives associated gear 35, gear 36, gear 37, gear 39, and gear 43.

The main arbor 41 is provided for attachment of a knob (not shown) for positioning thecam wheel 47 to the particular time desired for operation of the particular load involved. As shown more clearly in FIG. 2, cam wheel 47 is substantially fixed to and moves with arbor 41.

As shown more clearly in FIG. 2, the arbor 41 is coupled to I the gearwheel 43 by means of a friction disc 42 for purposes which will become apparent'as the description proceeds.

It will be obvious that through the properselection of gear trains, almost any displacement relationship can be obtained for movement of arbor 41. For the particular use designed herein, for instance, the gear train was selected at a 310 displacement in 60 seconds with the remaining 50 being reserved for purposes other than actual timing.

The main purpose for the remaining 50 is to provide a manual operation of the device wherein the ultimate load be allowed to operate with the timer disabled. This particular function has been provided in timers in the past only through the use of two sets of contacts, one for the load control and the other for the timer control. However, the present invention disposes of one of the sets of contacts, thereby reducing the cost of the device and further simplifying the mechanism involved therein.

In FIG. 1 the timer is shown in the manual position discussed above. The main arbor 41 has been turned to the position wherein contacts 45 are closed by cam 47 on the disc 59. Contacts 45 complete the circuit through leads 46 and 48 and further leads (not shown) to the device to be operated. Thus, the device is operative when the ON/OFF switch, 69 of FIG. 4, is closed.

The cam item 49 is integral with the.disc 40 and therefore turns in response to the manual rotation of the arbor 41. In the position shown in dotted lines indicated as 49a, the cam has been turned away from stop lever 51 and associated lobe 55 so that it has no action at all on the lever 51. If cam 49 is in the position as shown by the solidlines in FIG. 1, it can be seen that it has passed over lobe 55 and bears against the outer end of stop lever 51, forcing the lever to rotate clockwise about pivot 53. It will be noted that the other end of lever 51 ter minates in a downwardly extending finger 54. When the lever is rotated to the position as shown by the solid lines in FIG. 1, the finger 54 bears downwardly against armature 19 and prevents the armature from moving in response to the input current. This effectively disables the timer and removes it from control of the operating electrical circuit. Thus, there is provided a MANUAL" operating position.

Disc 40 contains an aperture therein which is associated with the closing of the contacts 45 so as to provide a quick break of the contacts 45. This is accomplished by the'associated use of the lost motion allowed by the slot 61 and pin 63 which is a technique well known in the time switch art. The upper cover plate 56 (a fragmentary view of which is shown in FIG. I) has an integral stop member 57 extending below the underside thereof. When cam 49 is in the full line position shown in FIG. 1, it is prevented from any further substantial counterclockwise rotation by stop member 57. Additionally, when cam 49 is turned to maximum time setting position 49b, it is prevented from further clockwise rotation by stop member 57.

When arbor 41 isturned clockwise to any desired time setting between an interval of time such as zero to 60 seconds, cam 47 in disc 59 and disc 40 are positively driven by arbor 41 and effect closures of contact 45. It should be noted that for very short operating time, because of the lost motion provision, the knob must be turned past the desired time and then returned in a counterclockwise direction to the desired setting.

During the above setting procedure, the timer gear train remains stationary due to the fact that the main arbor is frictionally coupled to the gear train as set forth above.

When the appliance start button (not shown) is depressed, the vibrator motor, which consists of the solenoid and armature, is energized so that for every half-cycle the spring 27 is moved downwardly so as to move the ratchet 31 in the sequence as shown in FIG. 3. FIG. 3a shows the device in the deenergized position with the airgap 65 open and the noback spring 33 preventing a counterclockwise rotation. FIG. 3b shows the energized position with the airgap closed at the end of the stroke and the no-back" spring in an unlocked position behind the tooth until the inertia of the entire system causes the full clockwise motion of the ratchet 31. FIG. 30 shows the device in a nonoverthrow condition. This occurs if the ratchet should continue to rotate beyond the required point. Under this condition, the ratchet spring 27 will butt against a stop 67 so as to prevent the passing of more than one tooth beyond the ratchet spring 27. In this position, it will be noted that the no-return spring 33 rides over and beyond one of the ratchet members.

FIG. 4 shows the general electrical layout schematically wherein an ON/OFF switch 69 is connected in series with the switch 45 controlled by the timing mechanism as described above. The coil 13 is connected in parallel with the load device which, in this case, is shown as motor 73. The coil effectively operates a gear train which is mechanically coupled to the cam 47 attached to the arbor which controls contact 45. As mentioned above, a ceramic magnet may be used in place of diode 14 to provide the half-cycle operation of the timer.

FIG. discloses a modification of the operating mechanism. In the operating sequence shown in FIG. 3, it will be noted that ratchet wheel 31 is rotated when the armature is energized, and the spring 21 merely biases the armature upwardly.

It may be preferable to operate ratchet wheel 31 upon the return of the armature whereby the force of the spring provides the mechanical force of rotation. Such an arrangement provides a constant-output torque driver, and is shown in FIG. 5 wherein the actuating spring 71 extends downwardly from the armature to form an elbow 73 and terminates at a slight angle at its outer end 75. Thus, spring 71 will pass over the associated tooth on the downward movement of the armature and will rotate the ratchet wheel on the return stroke. For this return stroke operation, the teeth 81 are angled in a direction opposite to that of FIG. 3. Therefore, the "no-back spring 71 is shaped with elbow 79 at its outer end to prevent clockwise rotation of the ratchet wheel.

As will now be obvious, the present invention provides a timer device which is accurate within a small error percentage of any time setting and is settable anywhere between a time interval such as zero to 60 seconds, or an interval as required by the design gear train. Further, it provides a hold feature which deactivates the timer and allows for manual operation of the electrical load.

it is to be noted that the above description and illustrative drawings are for purposes of description only and that the invention is to be limited only by the scope of the following claims.

I claim:

I. An electric timer comprising,

a solenoid including an armature responsive to one polarity of an alternating current in ut, ratchet spring means secure to and movable with said armature,

a ratchet wheel rotatable by means of said ratchet spring means,

manually settable means for closing a set of electrical contacts,

a gear train coupled at one end to said ratchet wheel and coupled at the other end to said manually settable means so that the movement of said ratchet spring means returns said manually settable means in predetermined incremental steps to the position wherein said electrical contacts are opened, and

a ceramic magnet abutting against said solenoid,

the flux of said magnet being in series with the flux of the coil of said solenoid so as to limit operation to said one polarity.

2. An electric timer comprising,

a solenoid including an armature responsive to one polarity of an alternating current input,

ratchet spring means secured to and movable with said armature,

a ratchet wheel rotatable by means of said ratchet spring means,

manually settable means for closing a set of electrical contacts,

a gear train coupled at one end to saidratchet wheel and coupled at the other end to said manually settable means so that the movement of said ratchet spring means returns said manually settable means in predetermined incremental steps to the position wherein said electrical contacts are opened, and

means for disabling the armature of said solenoid so that said timer is removed from control of said electrical contacts.

3. The timer of claim 2 wherein said means for disabling said solenoid comprises,

a pivoted lever arm,

cam means activated by said manually settable means for pivoting said arm, and

finger means on said arm for bearing against said armature when activated by said cam means.

Claims (3)

1. An electric timer comprising, a solenoid including an armature responsive to one polarity of an alternating current input, ratchet spring means secured to and movable with said armature, a ratchet wheel rotatable by means of said ratchet spring means, manually settable means for closing a set of electrical contacts, a gear train coupled at one end to said ratchet wheel and coupled at the other end to said manually settable means so that the movement of said ratchet spring means returns said manually settable means in predetermined incremental steps to the position wherein said electrical contacts are opened, and a ceramic magnet abutting against said solenoid, the flux of said magnet being in series with the flux of the coil of said solenoid so as to limit operation to said one polarity.

2. An electric timer comprising, a solenoid including an armature responsive to one polarity of an alternating current input, ratchet spring means secured to and movable with said armature, a ratchet wheel rotatable by means of said ratchet spring means, manually settable means for closing a set of electrical contacts, a gear train coupled at one end to said ratchet wheel and coupled at the other end to said manually settable means so that the movement of said ratchet spring means returns said manually settable means in predetermined incremental steps to the position wherein said electrical contacts are opened, and means for disabling the armature of said solenoid so that said timer is removed from control of said electrical contacts.

3. The timer of claim 2 wherein said means for disabling said solenoid comprises, a pivoted lever arm, cam means activated by said manually settable means for pivoting said arm, and finger means on said arm for bearing against said armature when activated by said cam means.

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