US2868923A - Timing device - Google Patents

Description

1 59 H; D. EPSTEIN 2,868 923 TIMING DEVICE Filed May 8, 1957 United States Patent 9 TIMING DEVICE,

Henry- David Epstein, Boston, Mass., assign or to Metals & Controts Corporation, Attleboro, Mass., a corporation of Massachusetts Application May s, 1957; Serial No. 657,802

8. Claims. (Cl. 2009-87).

This inventionrelates totimingdeviceS, and more particularly to a magnetic timedelay'relay for effecting relatively lohgftime delays. i i

Among, thefseye ral objects of. the invention may be noted the provision iof :an .electromagnctic timing device, and more particularly an adjustable time-delay relay, which utilizes an hourglass type of timer for time-measuring, purposes, whereby variable relatively long time delays may be obtained by appropriate selection and positioning of thevhourgla ss-iype timer; and the provision of atiming'device such as described which is of relatively simple and economical construction and reliable in operation. Other objects and features will be in part apparent and in partpointed out hereinafter.

The invention accordingly comprises the elements and combinations of. element s, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of which will be indicatedin the, following claims.

lnthe ac companying drawings, in which one of various possible embodiments of. the invention is illustrated,

Fig. l isa plan view ofa time-delay relay embodying the invention;

Fig. 2 is a frontelevation of Fig. l, with parts broken awayandin section, showing therelay at the start of a timedelay interval;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 2;

Fig. 4 is a fragment of Fig. 2 showing a moved position of parts; and,

Fig. 5 isa fragment-of Fig. 2 showing an adjusted position of parts.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring to the drawings, a time-delay relay embodying the invention consists of a magnet 1. This comprises a base 2. of nonmagnetic material, such as insulation, and;two magnetic members 3 and 5 constituting the coreQof the-magnet. mounted on the base. These core members may, be made of any suitable ferro-magnetic or magnetizable material such as iron, each being of oshape. They are mounted on the base, with their open sides toward one another, being spaced apart to provide an upper vertical air gap 7 providing a region of normally high reluctance between their upper arms 9 and 11, and a lower gap 13 between theirlower arms 15 and 17. These cores constitute means for providing a magnetic circuit or loop. For energizing this circuit or loop, a coil 19 is provided surrounding the vertical leg of core 5, for example.

A ferromagnetic armature 2 1 ispivotally mounted, as indicated at 23, on the lower arm 15 of core 3. The armature extends over the lower gap 13 (at a second region of normally high reluctance) and over the end of the lower arm 17 of core 5. It is biased by a spring 25 to swing upward to the raised retracted position in which it is illustrated in Fig. 2, wherein it is spaced from arm 17. It swings down on development of magnetizing force thereon sufiicient to overcome the bias of the spring.

2,868,923 Patented Jan. 13, 1959 At 27 is indicated a timer consistingof an hourglass type of container which has-two chambers connected a restricted opening. This hourglass member 27 is filled with a flowable ferromagnetic, low-reluctance material 29 such as finely divided iron, adapted to flowfrom the upper part or. chamber through the constricted central portion 31, to the lower part or chamber in a predetermined period of time. The particles-may be constituted by fine iron filings, carbonyl-Biron particles or the like. The member 27 is mounted to provide, for flow of the fluent magnetic material 29 relative to the upper gap 7 to change the reluctance of. the magnetic circuit provided by the cores 3 and 5 (and armature 21),from one limit to another in all or part of this period of time. For this purpose, the member 7 has its constricted central portion 29 mountedin a collar 33., A pivot pin 35 extends horizontally from the collar abovefthe gap 7 and parallel to the magnetic circuit (parallel to arms 9 and 11) through a bearing 37 which is mounted for vertical sliding move ment in averticalslot 39 in a vertical plate 41 mounted onarm9of core. '3. The bearing 37 has a flange 43, at its end away from theQhourglass member, which bears against the outer face of p late 41, and a spring washer 45 at its other end which bears against the inner face of plate 41. The bearing. 37 is vertically adjustable .by slid; ing itin slot39 and is held inanyadjusted position by the frictional engagement of flange 43 and washer 45 with the plate 41.

Fixedon the outer endof thepivot pin 35 isa knob 47. This knob carries. a spring-biasedball detent 49 engageable either in anupper indentation 51 or a lower indentation 53 formed in the face of flange 43 to determine-avertical position of member 27. Additional indentations such as indicated at 54 in Fig. 3 maybe provided to hold the glass in horizontal position. v The flange 43 carries a pointer 55 readable in conjunction with a time scale 57 on the plate,4 1- (see Fig. 3).

Mounted on the baselinthe gap 13 is a double-pole double-throw switch 59 operable by. the armature 21, This switch is shown as comprising avertically movable stem 61 carryinga pair. ofblades 63 and 65. It-hasan upper set of contact clips 67 and a lower set of contacts 69. Inthe raised position of the stern shown in Fig. 2, blade 63 is engagedin clips 67 and blade 65 is closed on contacts 69. The clips 67 hold the stem raised. The stem has a crosshead 71 at itsupper end engageable by the armature 21. When the armature swings down upon development of sufllcient magnetizing force thereon to overcome the bias of spring 25, it drives .the stem 61 down to disengage blade 63 from clips 67 and to open blade 65 from contacts 69(see Fig. 4). A load 73 isshown as connected in a circuit 75 including contacts 69. The coil 19 is shown as connected in a parallel circuit 77 including contact clips 67.

Operation is as follows:

The time-delay interval of the relay is set by adjusting the pivot pin 35 of the member 27 up or down, so that it takes more or less time for the fluent magnetic material 29 flowing from the upper to the lower part of the member 27 to fill the gap 7 and thereby reduce the reluctance of the magnetic circuit from a maximum to a minimum, Figs. 2 and 3 show the pin inits. lowermost position of adjustment, which means that the device is set for a time-delay interval corresponding to the period of time it takes the fluent material completely to flow from the upper to the lower part of the hourglass member. This is the maximum time-delay interval permitted. To initiate a time cycle, the stem 61 of the switch 59 is raised from its lowered position of Fig. 4 to its raised position of Fig. 3, and the member 27 is rotated to elevate the fluent material. Upon raising the stem of the switch, the coil 19 is energized to energize the magnetic circuit provided by the cores 3 and 5, and the load 73 is energized. At first, the reluctance of the magnetic circuit is near a maximum, since there is little magnetic material in gap 7, and the magnetizing force on armature 21 is a minimum. As the fluent magnetic material 29 flows into the lower part of the member 27 and becomes positioned in the gap 7, the reluctance decreases and the magnetizing force increases.

The device is designed, for example, so that the gap 7 must be filled with material 29 before the reluctance is decreased to the point where suflicient magnetizing force is developed for operating the armature. With the pivot pin 35 of the hourglass member in its lowermost position, as shown in Figs. 2 and 3, all the fluent material must flow into the lower part of the member before the gap is filled. When the flow is completed, the armature is pulled down. Thus, with the setting shown in Fig. 2, there is provided a time delay in the operation of the armature 21 which corresponds to the full time interval of the hourglass member. When the armature is pulled down, the switch 59 is operated to break the circuit 77 for the coil 19 and load circuit 75. Upon the resultant deenergization of the coil 19, the armature is returned to its raised position by the spring 25, but the switch stem 61 remains down until normally reset. To initiate another cycle, the stem 61 of the switch is raised by means of crosshead 71, and the member 27 rotated to elevate the fluent material 29 as before.

Fig. illustrates the pivot pin 35 of the member 27 raised to the top of the slot 39 for setting the minimum permissible time-delay interval. With the pin 35 set in this position, the gap 7 is filled in about half the time it takes the fluent material completely to flow from the upper to the lower part of the member. Settings of the pin 35 at positions between the limits shown in Figs. 2 and 5 provide various time delays between a maximum and minimum.

It will be understood that if the members 3 and 5 are composed of permanent magnetic material, the coil 19 may be omitted from the circuit L1L2. In such event, the sum of the reluctances of the gap 7 and the gap under the armature 21 is such that the armature 21 will not be drawn down when the ferromagnetic particles 29 are out of the gap 7. When they move into the gap, the reluctance is reduced, whereupon the armature 21 is drawn down, thus operating the switch in the circuit to be controlled.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above descripion or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A timing device comprising an electromagnet havingreduced as the fluent magnetic material flows into the lower chamber.

2. A timing device as set forth in claim 1 wherein said mounting means comprises a pivot for the hourglass member and a support for the pivot, the pivot being vertically adjustable with respect to the support and the core for vertical adjustment of the position of the lower chamber in the gap.

3. A timing device as set forth in claim 1 further comprising a switch for controlling a load circuit, and means for operating the switch in response to development of a predetermined magnetizing force by the electromagnet.

4. A timing device as set forth in claim 1 having a magnetizing coil for the core, a magnetizing coil circuit, a switch in said circuit, and means for operating the switch to open the circuit in response to development of a predetermined magnetizing force by the electromagnet.

5. A timing device as set forth in claim 1 having a magnetizing coil for the core, a magnetizing coil circuit, a switch for controlling said coil circuit and a load circuit, and means for operating the switch to open the coil circuit and vary the load circuit in response to development of a predetermined magnetizing force by the electromagnet.

6. A timing device as set forth in claim 5 wherein the means for operating the switch comprises a movable magnetic armature forming a part of said magnetic circuit, said armature being biased to a retracted position wherein there is a gap between it and the core, and being movable against the bias away from retracted position to operate the switch in response to development of a predetermined magnetizing force by the electromagnet.

7. A timing device comprising a base, an electromagnet having a core loop mounted on said base in vertical position, said loo-p having a gap in the upper part thereof, a time-measuring double-chambered hourglass member containing fluent magnetic material, means mounting said hourglass member for rotation on an axis located above the loop and in position to be rotated so that either one of the chambers of the hourglass member may extend down into the gap with the other above the gap for flow of the fluent magnetic material from the upper of the chambers into the lower of the chambers, the reluctance of the core loop being reduced as the fluent magnetic material flows into the lower chamber, said loop having a second gap, and a magnetic armature mounted for movement between a retracted position relative to said second gap and a position bridging said second gap, said armature being biased toward its retracted position, a magnetizing coil for the core loop, a magnetizing coil circuit, and a switch in said circuit operable by said armature.

8. A timing device as set forth in claim 7 wherein said mounting means for the hourglass member comprises a pivot for the hourglass member and a support for the pivot, the pivot being vertically adjustable with respect to the support and the upper part of the core loop for vertical adjustment of the position of the lower chamber in the gap in the upper part of the core loop.

References Cited in the file of this patent UNITED STATES PATENTS 2,086,754 Werner et al July 13, 1937 2,282,933 Cahill May 12, 1942 2,504,681 Hall Apr. 18, 1950 2,550,605 Schenck Apr. 24, 1951 2,555,513 Schweitzer June 5, 1951

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