US2349629A

US2349629A - Asymmetric device and mounting means therefor

Info

Publication number: US2349629A
Application number: US430642A
Authority: US
Inventors: Lazich Branko; Jr Richard H Williams
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1942-02-12
Filing date: 1942-02-12
Publication date: 1944-05-23
Anticipated expiration: 1961-05-23

Description

B. LAZICH ET AL ASYMMETRIC DEVICE AND MOUNTING MEANS THEREFOR A 4 9 1 3 2 V. M

Filed Feb. 12, 1942 EEC mh S m wwm 5 ma m W kH H f H 5 mm m M 9 n Patented May 23, 1944 AsrMME'mrc DEVICE AND MOUNTING Means 'rnnnnroa Branko Lazich, Wilkinsburg, and Richard B.

Williams, In, Pittsburgh, Pa assignors to The 1 Union Switch & Signal Company. Swissvale, Pa., a corporation of Pennsylvania Application February 12, 1942, Serial No. 430,642

3 Claims.

Our invention relates to asymmetric devices and to mounting means therefor In certain forms of electrical control apparatus which have been proposed for effecting one function or another according as a polarized control circuit is energized by current'of one relative polarity or the other, such for example, as the apparatus disclosed and claimed in an application for Letters Patent of the United States, Serial No. 424,151, filed by Arthur E. Dodd on December 23, 1941, apolar relay and an auxiliary relay are connected in series in the polarized control circuit through one or more elements of an asymmetric device and a polar contact of the polar relay, wherebythe auxiliary relay checks the response of the polar relay to changes in the polarity of the energy supplied to the polarized control circuit.

One object of our present invention is to provide an asymmetric device consisting of a novel assembly of asymmetric'units of the dry disc type for use in control apparatus of the type described, together with an improved mounting base therefor through which external circuit connections with the device may be made, said device and said mounting base being so constructed that the device can be readily plugged inte -gr removed from the mounting base, and that, vi l hen the device is removed from the mounting base any external circuits which are in multiple with any part of the device will be broken;

Another object of our invention is to provide an asymmetric device of the type described with novel means for automatically locking it against accidental displacement from its proper operative position with respect to the mounting base.

A further object of our invention is to so arrange the connecting prongs on the device and the cooperating contact clips in the mounting base that slight differences in the spacing of the connecting prongs, due for example to unavoidable differences in the thickness of the asymmetric units, will not affect the proper cooperative relationbetween the connecting prongs and the contact clips.

According to our invention, the device consists of a stack of asymmetric units, preferably of the well known copper oxide variety, assembled on a. clamping bolt in a manner similar to that in which the asymmetric units of a copper oxide rectifier are usually assembled, except for the fact that special contact plates are provided at each end of the stack and at one or more intermediate points in the stack. These contact plates are each provided with projecting contact prongs disposed at right angles to, and laterally offset from, the plane of the main body portions of the contact plates in such manner that by turning th contact plates around in the stack the distance between the contact plates can be changed to increase or decrease the available space for asymmetric unit without changing the spacing between the contact prongs. At least one of the contact plates is formed with a locking prong for cooperation with a locking spring provided in the mounting base to lock the device against accidental displacement when it is plugged into the base.

The mounting base is designed to partially enclose the-device to protect it from injury, and is provided, in addition to the locking spring referred to above, with contact clips disposed in recesses for cooperation with the prongs of the contact plates of the device.

Other objects and characteristic features of our invention will become apparent as the description proceeds.

We shall describe two forms of asymmetricv devices embodying our invention, and one form of mounting base therefor, also embodying our invention, and shall then point out th novel features thereof in claims.

In the accompanying drawing, Fig. 1 is an isometric view showing an asymmetric device embodying our invention, together with its associated mounting base also embodying our invention. substantially on the line 11-11 of Fig. 1. Fig. 3 is a longitudinal sectional view of the asymmetric device shown in the preceding views. Fig. 4 is a top plan view of the mounting base shown in Figs. 1 and 2 with certain of the parts broken away to better illustrate the construction of the remaining parts. Fig. 5 is an enlarged vertical sectional view of one of the asymmetric units forming part of the asymmetric device shown in Figs. 1, 2 and 3. Fig. 6 is a view showing a modified form of the asymmetric device shown in the preceding views.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawing, an asymmetric device embodying our invention is here shown as comprising a plurality of asymmetric units A of the dry surface contact variety, each consisting of a flat plate I of a metal, such as cop per, having a coating 2 of a compound of the metal, such as copper oxide, formed thereon (see Fig. 5). Asymmetric units of the type described exhibit the characteristic of offering Fig. 2 is a vertical sectional view taken a higher resistance to current which tends to flow from the copper to the oxide than to current tending to flow in the opposite direction through the unit.

The asymmetric units A are stacked on a clamping bolt 3 between two contact plates .4 and 5, and a third contact plate 6 is inserted in the stack in a position to divide the stack into two parts or legs, each preferably containing the same number of units. A thin washer l of an impressionable electrical conducting material, such as lead, is placed adjacent the coating 2 of cuprous oxide of each unit, and interposed in each leg of the stack are one or more spacer washers 8 which are provided to obtain a predetermined spacing between the contact plates. As shown, the units in the two legs of the device all face in the same direction, but the device may, where circuit requirements warrant it, be assembled with the units in the two legs facing in opposite directions, or by providing additional connectors not shown any arrangement of multiple connections within the physical limits of the apparatus may be obtained.

The units, the contact plates, and the yarious washers are all insulated from the clamping bolt by a sleeve 30 of insulating material which surrounds the bolt, and by two insulating washers 9 and Ill. The washer 9 is disposed on the bolt 3 between the head 3a of the bolt and the contact plate 4, and is provided at its outer face with a metal pressure distributing member 9a against I which a spring washer ll bears. The washer i is disposed on the bolt between the nut 3b and and the contact plate 5, and is similarly provided with a metal insert Illa against which a spring washer l2 bears. The two spring washers Ii and I2 serve to maintain a uniform pressure on the parts, whereby the impressionable conducting plates are firmly pressed into intimate contact with the oxide coating of the units.

For many applications, it is desirable to be able to plug an asymmetric device of the type thus far described into a mounting base through which external circuit connections with the device may be made, whereby the device can be quickly removed and replaced with a similar device without disturbing the external circuit wiring. Furthermore, since in many applications the two legs of the device are connected in multiple with various circuit apparatus it is desirable to insure that when the device is removed from the mounting base, all multiple circuits will be broken. To this end, we provide each contact plate with two integral prongs a and b located on opposite sides of the plate. These prongs are disposed at right angles to the main body portion of the contact plates, and are laterally offset -from the main body portion of the plates for a reason which will be made clear presently.

The mounting base in the form here shown comprises two moulded parts It: and i6 secured together by means of two screws 11 which pass through clearance holes provided in opposite corners of the lower moulded part l and are screwed into threaded inserts 18 provided in the upper moulded part It. The remaining corners of the two moulded parts are provided with vertically aligned holes H which align with inserts [8 provided in the part l6 through which screws or bolts may be passed to secure the base to a mounting rack or other convenient support.

The mounting base is adapted to partially enclose the asymmetric device to protect it from injury, and for this purpose the upper moulded part It is formed with a semi-cylindrical recess 2. having a radius oi curvature slightly larger than the radius of curvature of the asymmetric units, and a depth sumcient to receive the major portion of the asymmetric device. A plurality of slots 2| are provided in the part II on opposite sides of this recess in positions to receive the prongs a and b of the asymmetric device when the device is lowered into the recess 20, and these slots each communicate at their lower ends with a recess 22 formed in the part It directly below the associated slot. Disposed in each recess is a female contact clip or connector 23 which is adapted to engage the contact prongs on the device when they are inserted into the slots 2| and thereby make electrical contact therewith. The connectors may have any desired construction, but as here shown each connector comprises two separate contact members, each having a tail portion 23a and a body portion 23b disposed at right angles to the tail portion. Each body portion is formed with a U-shaped return bend so constructed that when the con tact members are in place in the slots 22 their inner legs are urged toward each other due to their inherent resiliency. The connectors are inserted into the recesses 22 before the part it is secured to the part i5 and are held in place in the recess by the part IS. The tail portions 23a of the connectors project through the side of the mounting base, and are provided at their outer ends with through holes 23d, and with notches 23c to facilitate securing circuit wires to the connectors.

In constructing asymmetric devices of the type described it is extremely diflicult to cause the contact plates 4, 5 and 6 to always be spaced apart the same distance for the reason that the thickness of the oxide coating on different units A varies even when the units are made under the most exacting conditions, and for the further reason that when the nut 3b is tightened, the impressionable metal in the washers 1 tends to flow a, slight amount which amount varies somewhat in diflferent devices. In order to allow for this variation in spacing between the contact plates, and still permit the device to be readily plugged into the mounting base, the contact prongs a and b are disposed at right angles to the plane of the plates in the manner previously described, and the slots in the mounting base through which the prongs extend have been made longer than the width of the prongs by an amount which is at least equal to the difierence in spacing between the plate encountered in practice.

It should be particularly noted that with this arrangement of the prongs and slots, variations in the spacing between the contact plates does not change the contact pressure between the contact prongs and the circuit connectors in the base as might happen for example if the prongs were disposed in the same plane as the contact plates and the connectors were rotated through an angle of from the position shown.

When the device is plugged into the mounting base, it is desirable to prevent it from being displaced, due for example, to vibration, and for this purpose one of the contact plates, here shown as the middle contact plate 6 is provided with. a locking prong 24 which projects into aligned

slots

25 and 26 formed in the two base parts l5 and I6, and cooperates with a hair pin spring 21 disposed in a recess 28 formed in the underside of the upper part 16 of the base. When the prong 24 is in place in the

slots

25 and 26, the legs of the spring, due to their inherent resiliency enter notches 28a formed in the opposite sides of the locking prong and thus grip the prong to thereby latch the device in place in the base. The spring 21 is maintained in the desired position in the recess 28 by depending rounded projections 29 moulded on the part it and extending into the recess in the manner shown. To facilitate forcing the two legs of the spring apart when the locking prong is being inserted into the aligned

slots

25 and 26, the lower end of the lockin prong is pointed as shown.

In at least one application of asymmetric devices of the type described each leg of the device is connected in multiple with the winding of a different relay, and the construction of the device described enables all circuits for the relay windings to be completed through the contact plates of the device, whereby when the device is removed from the mounting base, the relay cir- 2o edits are all open, thus insuring against false circult operation due to the removal of the asymmetric device from the circuit.

The eifective resistance of the device between 25 the middle and two outside contact plates depends upon the number of units connected in V series between the plates. It is sometimesdesirable to be able to assemble a greater number of units in each leg of the device to change 30 its resistance characteristics, and still be able to plug the device into the same mounting base.

between the contact plates can be provided by removing the spacer washers I provided in the two legs of'the stack.

If a smaller number of units are desired betwmn the contact plates, additional spacer washers may be provided sumcient in number to maintain the spacing between the plates necmsary to enable the device to be plugged into the moun base.

though we have herein shown'and described two forms of etric devices embodying our invention and one form of mounting base therefor, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

minal members in laterally oitset relation in such manner that by turning the terminal members around in the stack the distance between the ter- 4 minal members can be changed to provide a greater or lesser space for asymmetric units between them without changing the distance between the contact prongs, whereby the same mounting base can be used for different devices having difleront numbers of asymmetric units included therein.

2. An asymmetric device comprising a stack of asymmetric units, terminal members disposed in 0 said stack and provided with contact prongs, a

mounting base provided with slots for receiving said prongs and with recesses communicatin with said slots, and circuit connectors disposed in said recesses and adapted to engage said prongs to make electrical contact therewith, said prongs being disposed in planes extending parallel to the axis of the stack and said slots being made longer than the widths of the prongs and the engaging surfaces of the circuit connectors being disposed in longitudinal alignment, whereby the prongs can be inserted into engagement with the circuit connectors without distorting the parts irrespective of slight diflerences in the longitudinal spacing of the contact prongs.

3. As a new article of manufacture an asymmetric device provided with terminal members having contact prongs for plug-in engagement with a mounting base, said contact prongs being disposed at right angles to and laterally oil-set from the plane of the main body portion of the associated terminal member for the purpose set forth.

BRANKOLAZICH.

1 RI H.