US2444146A - Timing switch - Google Patents

Description

June 29, 1948. E. L. scHELLENs TIMING SWITCH Filed Feb. 8, 1944 I Z/ 23 ZZ L nl.

INVENToR (i4 d Wl ATTORNEYS.

Patented June 29, 1948 TIMING SWITCH Eugene L. Schellens, Essex, Conn., assignor to e R. W. Cramer Company, Incorporated,

Centerbrook,-Conn., a corporation of Connecticut Application February 8, 1944, Serial No. 521,529

' 4 Claims.

1 This invention is a novel timing switch of the kind in which there is to be regulation or timing of the operation of some industrial or other process or apparatus, typically where an alternating or other current is to be supplied intermittently to the operation. In the use of such timing switches it is often desired to proportion adjustably the on and off intervals of operation or closed circuit. There are many practical instances wherein such regulation is desirable, for example where there are to be alternate functions or operations desired to bear a definite time relation to each other, for example, each of the `two functions to prevail during an interval which is a definite proportion of the tota-l time period or cycle of the operation. One instance is the case of an electric furnace, oven or heater which is desired to be under electric heat for a certain fraction or percentage of each cycle and free of such .heat during another fraction or interval, or for the balance of the cycle. Other instances include the intermittent feed of chemicals to some operation, for example by the introduction of agents into a vessel or boiler for the treatment of the water therein, which may be desirable for only a few minutes of each hour.

The main object of the present invention therefore is to afford a timing switch which can give automatic control of the percentage or interval of time at which a given regulating or operating circuit is to be closed or open during each predetermined definite period of time, which may be considered as the cycle of operation. Taking the case of a one minute cycle or total period the timing switch of this invention may be used for example to maintain the output circuit of the apparatus open or broken for 40 percent of the cycle and closed for the remaining 60 percent thereof; in other words open for 24 seconds and closed for 36 seconds during each (iO-second period. By ready readjustment the closed interval may be set to 75 or 50 or other percentage.

Further objects are to provide a timing switch of the kind referred to which is accurate and reliable in operation, simple in design and durable in construction. A particular object is to provide such a. switch wherein the proportioning of the time intervals may be readily adjusted at will or in accordance with changes of condition, namely, by an exterior adjusting means or handle, which may be operated manually or otherwise during the running of the apparatus or process and without the need of suspending operations or loosening or removing parts of the switch; so that shutdowns of process may be avoided and any disturbance eliminated of the main operations and the efficiency thereof. Other objects and advantages of the invention will be pointed out in the hereinafter following description of an illustrative embodiment of the invention or will be understood by those conversant with the subject. It is to be understood that while the illustrated example shows the total period or repeating cycle to be subdivided into two intervals, the same principles may be used for proportioning the cycle into three or a greater number of intervals, each of a definite percentage.

In the accompanying drawings,

Fig. l is an exterior elevational view in perspective of a timing switch, embodied in a casing or housing, and embodying the principles of the present invention, the switch being shown with its axis in horizontal position as though mounted on an instrument board.

Fig. 2 is a view of the timing switch of Fig. 1, set up however into a vertical position, and shown with its casing parts in central vertical section but its interior parts in front view elevation.

Fig, 3 is a top plan View of the switch shown in Fig. 2 but with the casing top portion or cover removed, and certain parts omitted which extend above the crooked section line 3 3 of Fig. 2. In

Figs. l, 2 and 3 the parts are shown in what may be designated their zero or initial position, this setting giving no open-circuit interval.

Fig. 4 is a top plan view similar to Fig. 3 but with the operating parts shown in different positions, this setting giving about 40 percent open and percent closed intervals.

Fig. 5 is a righthand elevation view of certain interior parts, looking from the righthand side of Fig. 3.

Fig. 6 is a rear elevation view of the timing switch shown in Fig. 1, or a bottom view of the same in its Fig. 2 position, and showing diagrammatically certain elements of the operating and output circuits of the switch.

The invention may be considered as an automatic timing switch having a predetermined total period of cyclical operation, repeated cycle after cycle, and operable to reverse a controlling or output circuit as between the closed and open condition thereof, namely, at an adjustably variable fraction or percentage or interval of each cycle or period. Before describing the details the p invention may be outlined as comprising the following combination. There are a plural number of substantially similar spiral-contoured rotary cams 35 and 45 mounted for independent but coaxial rotation, the first or passive cam 35 being case with an interval of 40 percent followed by y an interval of 60 percent of each total cycle; the second or active spiral cam 45 having a driving means or motor 25 for rotating it steadily during each cycle; a lirst switch arm 35 movable outwardiy from its zero position to a selected or set position by the adjustable turning of the first cam, as seen by comparing Figs. 3 and 4; a second switch arm 45 shiftable outwardly in a steady manner during each cycle from an initial or inward position by the driving rotation of the second cam 45 until released to return to initial position after reaching the outer terminus of the spiral and dropping off therefrom; a pair of electrical contacts 4I and 5I adapted to meet and separate mutually to control the circuit, said contacts being so arranged and related to the first and second switch arms that when the arms are in corresponding positions, due to the first and second cams being in corresponding positions, the contacts are in Amutual contact, but

when the first arm is by its cam set outwardly g beyond the second arm the contacts mutually 'separate and break the circuit. By this simple arrangement, when the first cam is once adjustably set beyond its zero position the second cam in eachcycle, by its steady motor drive, effects the following actions, (a) it throws the second arm outwardly through a predetermined interval of the cycle until thisarm overtakes the selectively set first arm and thus brings the contacts into contact, and (b) therebeyond through the remaining interval causes the second arm to thrust the first arm, both arms moving outwardly and thus maintaining closed the circuit, until at the cycle end the second arm drops or runs off the second cam, allowing both arms to return, the rst arm to its selected position and the second arm to its initial position, ready for immediato repetition of operations.

In the preferred and simplest arrangement the first and second contacts are mounted directly upon the first and second switch arms, being so arranged that the set position of the first contact stands in the path of the second contact as the second cam shifts outwardly the second arm, whereby in each cycle the second contact catches up and overtakes the first at a selected point of time depending upon the adjustment of the first cam, and from and beyond this point the second arm and contact thrusting outwardly the first contact and arm, as permitted by the spring yielding thereof, thus maintaining closed the circuit until at the cycle end the two arms and their contacts return respectively to their selected and initial positions.

Referring to the detalls of the illustrated structure the casing or housing preferably comprises a back half or base section Il) and a front or top half II .constituting a cover; the entirety being preferably cylindrical and composed of a nonconducting plastic such as Bakelite. The interconnection of the base and top sections is by means of upright bolts I2 passing through interior bosses or lugs. The top section is preferably formed with an outstanding flange I3 by which the switch may be mountedflushly on a switchboard or elsewhere, where it may be secured by means of clamping rings or straps I4.

The casing top wall I5 gives support to a dial I8 which may be calibrated in various convenient ways, such as in percents of the cycle, although the calibrating may be designed for special uses, indicating special magnitudes or quantities, as of gallons, pounds and the like. As seen in Fig. l the dial may have a zero point I1 from which the calibrations start, and when the switch is so set the first or settable cam stands in a zero position corresponding to the initial position which the second or driven cam assumes between cycles, as seen in Figs. 2 and 3.

In general the interior parts may be positioned and held in place within the casing by means of a cross wall or diaphragm I in the nature of a circular partition or plate which is located and clamped between the base and top sections of the casing. A principal elementcarried by the partition I8 is a fixed vertical stud or axle Il, which may be welded to the partition or otherwise secured and stands upwardly to serve as an interior bearing or axle for the rotating parts to be described.

Upon the fixed upright axle I9 as a bearing there turns a hollow shaft 20, which is motor driven, and is in the nature of a hub carrying, slightly above the partition, a spur gear 2| and thereabove the driven cam to be further described. For the purpose of steady rotation of the hollow shaft or hub 25 and the cam carried thereby there is shown provided a pinion 22 which engages and drives the gear 2I and whichl in turn is driven through its mounting at the top end of the output shaft 23 of the gear box 24 of a continuously rotating motor 25. The pinion shaft 23 passes through an offset aperture 25 in the partition plate I5. The motor should have steady speed of rotation, and may be a synchronous electric motor, the speed of which, as reduced by the gearing in the gear box 24 and by the pinion 22 driving the gear 2l determines the rotation speed of the driven shaft or hub 2D and thereby predetermines the period of each cycle of the operation of the switch.

Referring now to the mountings and operations of the first spiral cam 35, this preferably takes its bearing upon the upright axle or stud I9, above the second cam 45. A convenient mounting is by means of a collar 25 surrounding the axle I9, this collar being in the nature of a split hub or socket, positioned coaxially above the driven hub 20 and preferably providing frictional resistance between the fixed axle and the upstanding spindle 29 which carries thel collar 28 and the first cam l5. This slip mounting of the cam spindle permits the spindle and first cam to be set to a selected position, where they tend to remain stationary by reason of the friction provided between the axle and the spindle as described. The spindle is shown extending through the top half of the casing and out through the casing top wall I5 to an exteriorly accessible point, with further friction means interposed between the spindle and the wall I5 if desired. At its upper or outer extremity the cam adjusting spindle 29 is provided with a setting handle shown in the form of a manual knob 35; and this knob or the spindle carrying an index or pointer 3l which plays around the dial I5. When the index finger 3l stands at the zero position I1 as seen in Fig. i the spindle and connected parts take the zero position as shown in Figs. 2 and 3,

of operation. When the handle 3l! is set to the zero position the electrical contacts are always in contact, so that there is no open condition of the switch, which remains with its contacts closed throughout 100 percent of the cycle. When however the pointer is rotated around counterclcckwise in Fig. 1 to an advanced selected position, such as at the 40 percent mark, the switch will remain open for 40 percent of each cycle followed by closing for the remaining 60 percent lnterval, as will further appear.

The first or settable spiral cam 35 is the uppermost one and is mounted on the spindle 25 and is thereby adjustable by the turning of the spindle by the 'handle 30. The cam is described as a spiral cam, and it is preferably a regular spiral, being an open cam with a uniform rate of rise causing the outswing of the first switch arm as the parts are moved to their selected set position. Cooperating with the first spiral cam is the first switch arm 36, adapted to shift outwardly by the thrust of the cam. The arm 36, and as well the arm 46 lto be described, are shown as swingable upon a fixed stud or axle 3l mounted upon the upper side of the diaphragm or partition plate I8; and preferably both of the switch arms are of non-conducting` material such as Bakelite. For cooperation with the cam 35 the arm 36 is provided with a follower 38, which may be a separately constructed wear-part attached to the extremity of the arm, and `the tapered extremity of this follower is arranged to bear upon the periphery of the spiral cam, so that the turning of the cam swings outwardly the switch arm, there being provided a spring means,shown as a tension spring 39, with one end attached to an upright post 40 and pulling inwardly upon the arm, thereby to maintain the follower 38 in contact with the open cam. By this arrangement the first switch arm can be selectively adjusted from its innermost or zero position outwardly to the selected position, for example as seen in Fig. 4 while at the same time the spring pull of the arm toward the cam permits a further yield of the arm for the purposes of the cooperative action already described.

The second spiral cam 45 is driven steadily by its motor and it cooperates with the second switch arm 46 whose follower 48 bears on the cam periphery, a spring 49 attached to pos-t 4@ holding the arm to the cam and, when the fcllower passes oil' of the outer terminus of the spiral, restoring the arm to initial inward position, with a quick or snap action. The two cams 35 and 45 are substantially equivalent or similar in contour, or preferably identical for simplicity in manufacture and operation, and the spiral shape affords a desirable gradual outthrow and sudden return or snapback of the second switch arm.

Coming next to the pair of contacts 4| and these are operated relatively to each other by the joint action of the two switch arms. Thus, the first contact 4| is shown mounted on the settable arm 36, with a binding post 42 for connection of a circuit wire 6|. 'Ihe second contact 5l is shown mounted on the regularly oscillated or driven arm 46. By an offset piece 50 the two contacts are arranged in the same path of swing, so that the second contact, on each outthrow, meets the first contact and thus `closes or reverses the circuit condition; in this case the contact 5| being offset from its arm so as to. overtake and strike the contact 4|. The contact 5| is connected with a binding post 5! from which extends a second circuit wire or connector l I.

The operations of setting the selectively adjustable or passive cam 35, and of' driving the active or operating cam 45, and the resulting proportional or percentage control of the output circuit through contacts 4| and 5| have been indi-` tom wall, with interior conductors 51 from the lterminals to the motor 25. By an exterior switch 58 the energizing current can be applied or cut off at will. The motor 25 may be of the synchronous kind and for example of the shift-unit type, with speed-reduction gear-box 24 and terminal shaft 23, for further details of which reference may be made to the Schellens Patent No. 2,334,040, patented November 9, 1943.

For the output circuit the casing carries screw terminals 60 which respectively are connected by interior conductors or wires 6| with the timing switch contacts 4| and 5| on th-e movable switch arms 36 and 46. Exteriorly are shown conductors 63 extending to the load or place of operation of any sort, for which any source of current may be provided, conventionally indicated as a battery t4.

While the invention may be embodied in various arrangements of elements, that shown has proven satisfactory. rThe two arms swing about a common axis parallel to but spaced from the axis of the cams. The fol-lowers both face inwardly toward the cam axis, and that on the settable arm is longer than the other so that the first arm stands ahgularly further out, in all `positions, including the case when the settable cam is at zero and the driven cam at initial position. By this is afforded a convenient angular space between the arms for locating on the arms the electrical contact-s, the first outwardly of and in the path of the second. The two cams as well as the followers are preferably of hardened metal, for wear, so that the followers may have simple tapered extremitieswithout the need of rollers.

vThe combined arrangement of the switch contacts and the plurality of cam-actuated switch arms is for the purpose of affording relative movability so that the relative cam operation of the arms causes the contacts to come together in one action or to separate in the reverse action, thus closing or opening the switch circuit.

What is claimed is:

l. In a percentage timing switch with cyclical operation, of the kind disclosed, a first and a second spiral disk cam of similar outline mounted coaxially for independent turning, their spiral contours trending outward from their axis; the first cam being adjustably settable to a selected position representing subdivision of each cycle into predetermined intervals of desired percentage and when set acting passively as a stationary stop, the second cam having driving means for rotating it steadily through cycle after cycle; a first arm with follower spring-pressed inwardly toward the cam axis to maintain engagement with the rst cam and adapted to take a selected position by the setting of its cam and yleldingly to swing outwardly therefrom in a plane at right angles to the cam axis, a second arm with follower spring-pressed to maintain engagement with the second cam and thereby to be driven swingingly outwardly from its initial inward position in a plane at right angles to the cam axis until dropping of! the outer terminus of the cam at the end of each cycle for return to initial position, a ilr'st electrical contact associated with the rst arm and a second contact associated with the second arm, the nrst contact being in the path of the outwardly moving second contact: whereby during each cycle, with a given setting of theilrst cam, the second arm and contact approach the rst during a ilrst interval while the circuit of the contacts is open, until the second arm and contact overtakek the ilrst causing the closing of the circuit, which'remains closed for a second interval as the first arm and contact yield outwardly with the thrustof the second arm and contact until at the cycle-end the second arm is restored inwardly to its initial position while the first arm returns to its selected position, forl position of the first relatively to the second arm and contact, and the second cam having means to drive it steadily to cause gradual outward and quick return movements of themsecond arm and contact in each cycle; said arms being mounted to move outwardly and inwardly in planes at right angles to the common axis of said cams;

whereby during the rst interval of each cycle the contacts are separated until the second overtakes the adjusted rst contact whereafter the contacts remain in contact substantially to the end of the cycle.

3. A timing switch as in claim 2 and wherein is a casing having a partition wall with a ilxed axle thereon, the settable cam having a friction collar engaging said axle and extended lfrom said collar a spindle carrying an exterior setting handie, and the driven cam having a hub or sleeve turning on said axle with a gear by which it is continuously drivenj the driving means comprising a synchronous motor and reduction gearing from the motor to the driven hub gear. f

4. A timing switch as in claim 2 and wherein the arms are swingable about a common axis paralle] to but spaced away from the common axis of the spiral cams. with the arm followers facing inwardly toward the cam axis; the follower of the settable arm being longer than thatl of the driven arm. whereby at zero position the settable arm stands spaced angularly outward of the driven arm at initial position, and the respective contacts being accommodated in the angular space between the two arms.

EUGENE L. SCHELLENS.`

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

UNITED STATES PATENTS Number Name Date 594,306 Williams Nov. 23, 1897 2,275,912 Newell Mar. 10, 1942 2.294,961 Carlson Sept. 8, 1942 2,366,454 Patee Jan. 2, 1945

Images