US2377872A - Multiple contact lamp hanger - Google Patents

Description

June 12, 1945.

T. B.\FARRING'I"ON ET AL ,377,872

MULTIPLE CONTACT LAMP HANGER Filed April 21, 1944 3 Sheets-Sheet l INVENTORS:

THAYER B. FARRiNGTON ROBERT K. FARRMGTON HAROLD L. DALZELL BY Q 2 ATTORNEYS.

June 12, 1945. T. B. FARRINGTON ET AL MULTIPLE CONTACT LAMP HANGER Filed April 21, 1944 3 Sheets-Sheet 2 H H H ii June 12, 1945.

T. B. FARRINGTON ET AL MULTIPLE CONTACT LAMP HANGER Filed April 21, 1944 3 Sheets-Sheet 3 FIG. 4

' INVENTORS:

THAYER B. FARRWGTON ROBERT K. FARRINGTON HAROLD L. DALZE LL ATTORNEYS Patented June 12, 1945 MULTIPLE CONTACT LAMP HANGER Thayer B. Farrington and Robert K. Farrington. Cleveland Heights, and Harold L. Dalzell, Cleveland, Ohio, assignors to The Thompson Electric Company, Cleveland, Ohio, a corporation of Ohio Application April 21, 1944, Serial No. 532.117

4 Claims. (Cl. 248-319) This invention relates to improvements in an electrical device having multiple contacts which are separable and particularly to the application of such a device in a lowering lamp hanger.

An object of the present invention is to provide means for supporting separable contacts in a simple but efiicient manner providing for the necessary adjustment of the coacting pairs of contacts when making and breaking the circuit.

The details of our invention are clearly disclosed in the accompanying drawings and essential features thereof will be set forth in the appended claims.

In the drawings Fig. 1 is a side elevational view partly broken T away in section and illustrating one form of our device; 2

Fig. 2 'is an end elevational view of the device of Fig. 1 partly broken away in section to more clearly illustrate the construction;

Figs. 3 and 4 are transverse sectional views taken along similarly numbered lines of Figures 1, Fig. 4 showing the bracket only, for clearness;

Figs. 5 and 6 are top plan and side elevational views respectively of a contact-supporting bar forming part of the device shown in Figs. 1 to 3;

Figs. 7 and 8 are top plan and side elevational Views respectively of an insulator block for the movable contacts; while Fig. 9 is half a top plan view taken in a position similar to Fig. 3 and showing a modified form of equalizer bar arrangement.

Our device performs a function similar to that disclosed in U. S. Patent No. 2,290,143, granted July 14, 194.2, to Thayer B. Farrington, although the present device utilizes differently constructed parts the advantages of which will be hereinafter pointed out.

As in the above-mentioned Farrington patent, we have shown our device as applied to coacting lamp hanger members wherein the fixed member comprises a canopy I for supporting certain of the parts and for protecting the separable contacts from the weather. Rigidly secured with the canopy is a tubular guide I I adapted to receive within its hollow interior a stem I2 which car-- ries the lamp which. is lowered. When the lamp is held in its raised position. the stem I2 is latched in the guide II by means of a latchdog I3 which is more clearly described in the abovementioned Farrington patent. A chain or other flexible tension member I I has its end I4a secured, in the stem I2. The chain passes upwardly through the hollow stem and around a pulley I which is rotatably supported in a bracket I6, screws I1 uniting the bracket, canopy, and guide in a rigid assembly. It will be understood that the chain I4 passes from pulley I5 to a remote point from wh ch the lamp is manipulated. Two insulator blocks I8 one seen at the right of Fig. 1 and one in similar position at the left hand side not shown.

are fixedly secured to the canopy II). A contact I9 of cup-shape opening downwardly is secured to each of the insulator blocks I8. Electrical conductors not shown are connected between the contacts I9 and a source of current. I

Our improvement is embodied in the separable contacts which coact with the contacts I9 and which are carried by the lowering hanger member connected with the stem I2. A bracket 20 is provided with the centrally located downwardly extending cylindrical spring housing 2011. A spring 2| is held in compression between the flange I2a on the stem I2-and the flange 201) on the bracket. Just above the flange on opposite sides of the opening 200 are provided notched recesses 20d to receive projections I2b of the stem when the parts are in latched position as shown in Figs. 1 and 3. An adapter 22 is threaded into the lower end of stem I2 and in turn carries ,a lamp or other electrical device supplied with current through the conductors 23 which. lead downwardly from the movable contacts and enter through suitable openings 22a of the adapter.

When the parts are in the operative position of Fig. 1, the lowering hanger member is released by pulling on the chain I4, compressing spring 2| until latchdog I3 is released, whereupon the stem 12 Carrying wi t the.bracket 20 with its associated contacts and the adapter 22, lamp, etc., may be loweredto any desired point. When it is again desired to elevate the lamp or other electrical device, the chain I4 i pulled until the stem I 2 enters the guide I I. The parts are always caused to re-engage in a definitely oriented posi tion by means of afin I2c which rides on one or the other of cam surfaces I la until the fin enters a slot at I lb, all as described in the abovementioned Farrington patent to which further reference may be had for details of this orienting mechanism. I

The upper and outer portions of bracket 20 are arranged to support a plurality of electrical contacts for equalized engagement with the contacts I9 when the parts are in the latched position shown in Figs. 1 and 2. For purposes of illustration, we have shown four contacts I9 with four coacting movable contacts although other arrangements of our device are possible as suggested in the above-mentioned Farrington patent.

One place Where a four-contact device is useful i where standard incandescent lamps and mercury-arc lamps are supported in the same fixture attached to adapter 22. In such a case, different voltage is necessary for the two lamps, and, in the present instance, we have shown two contacts for each voltage or a total of four.

The upper portion of bracket 26 is clearly shown in plan view in Fig. 4. This portion of the bracket is generally rectangular in shape and has two openings 20c extending entirely through the bracket at each end thereof on opposite sides of the spring housing 20a. Each of these openings is generally rectangular in shape and is adapted to receive a pair of insulator blocks 24, each of which in turn supports a movable electrical contact 25. The insulator blocks are best seen in Figs. '7 and 8. Each block has a substantially square neck 24b below which is a skirt 240 which has a curved outer surface toward the left-hand side as viewed in Figs. 7 and 8 and a fiat surface 24d on the right-hand side. A central opening 24c through the block serves to receive a bolt 25 which secures the contact 25 in place. It

will be noticed that the top surface of the contact E is arcuately formed so that each contact will tend to center itself with the coacting fixed contact iii. A conductor 23 is electrically connected with each bolt 25 by means of a nut 21.

The purpose of the special construction of the i insulator blocks 24 just described is to enable them to coact with a supporting bar 28 and with the bracket 28. There are two of these supporting bars, each pivotally supported intermediate its ends above one of the openings 206. For this purpose, upstanding ears 28a on each bar are provided with openings which register with similar openin s in cars 28] whi h extend upwar ly from bracket on both sides of each opening 2{!e. Pins 29 pass throu h these re istering openings so as to provide a pivotal mounting for each bar .28 intermediate its ends. On op osite sides of its pi ot, each bar is bifurcated providing parallel arms 28b. These arms are so spaced that they are received in the grooves on opposite sides of the square neck 24b of the insulator blocks. Thus. a pair of blocks 24 may be slid into position entering at the o en space between a pair of arm 28b. Each block is thus held on bar 28 for oscillating movement about pin 29 and for limited latera sliding movement on the arms 2827. In assemblin the parts. the blocks 24 are first placed in position on the arms 28b and then bar 28 is moved into position to receive pin 29. When this pin is in place. the blocks 24 cannot escape from the sunporting bar 28 because the flat side 24d of each block is adiacent a fixed portion of bracket 28 as clearly seen in Fig. 3 at the u'oner right-hand corner. and in dot-da sh lines in Fi 4.

It results from the above construction that when the lowering han er member is raised into position. the bracket 20 may tilt in the plane o the paper as viewed in Fig. 1 due to its resilient mountin on sprint. 2|. There ore. the two conta ts 25 at one end of bracket 20 have an op ortunity to equalize contact pressure with the other pair of contacts 25 at the opposite end of the bracket. At the same time the two contacts 25 at one end of the bracket, say at the right-hand end as viewed in Fies.,2 and 3, have an o portunity to equalize contact pressure by oscillation of bar 28 about the pivot 29. All four pairs of coacting contacts thus equalize their contactin pressure and are all held in resilient engagement b spring 2| as shown in Fig. 1. The device is thus very efiicient for its intended purpose and comprises but a few parts which are easily constructed and readily assembled.

In Fig. 9 we have shown a modified form of equalizer bar, it being understood that Fig. 9 is taken in a position similar to Fig. 3 with the canopy l0 omitted. Since this device is symmetrical about the center line, the right-hand half of the view has been omitted. Here the bracket 23' is exactly like the bracket 20 previously described except for certain differences which will now be pointed out. Instead of forming the opening 20s in the bracket as described in connection with our first form, the bracket is cut off at each end along the line 30. There is only one ear 26) for supporting the equalizer bar at each end of the bracket. Here equalizer bar 3! is provided with a centrally-located upstanding ear 31a through which extends a shoulder bolt M which is threaded into the ear 20/.

This provides a centrally-located pivot for the bar 3!. Each end of the bar is bifurcated but here the bifurcations extend parallel to the pivot bolt 32 as distinguished from the previously described bifurcations of the bar 28 which extended at right angles to the pivot pin 29. One arm of each bifurcation is indicated at 312), the other arm being provided by the central portion of bar 3 l. The opening in each bifurcated arm is adapted to slidingly receive the neck 24?) of insulator blocks 24 which are similar to those previously described. These insulator blocks have a fiat side 24d which is adjacent the end edge 30 of the bra ket 29'. Each insulator block carries a contact 25 for engagement with the contacts I! shown in Figs. 1 and 2. This form of our device is assembled by sliding the insulator blocks 24 into the bifurcations of bar 3| after which bolt 32 is passed through ear am and screwed into ear 23]. Each insulator block is then slidably mounted on bar 3| and prevented from sliding of! bv the ed e 38 of bracket 20'. The device of Fig. 9 is mounted on stem I2 and will operate exactly like the first described form of our device.

It is necessary that the fixed contacts H! be accuratel positioned so as to properly cooperate with the movable contacts 25. To this end each fixed insulator block l8, as best seen in Fig. 2. is provided with. two recesses lBa which are square in cross-section to receive the nut 33 and hold it from tu ning. This nut secures the contact I9 to the block l8. Nibs 34 are cast on the canopv in in the form of a frustum of a cone. It results from this constr c ion that when bolt 35 is pas d throu h a suitable centrally loc ted o ening lflb in block 18 and threaded into canopy i l. the souare recesses 18a ride on the sloping sides of the nibs 34 to accurately position the block so as to insure perfect alinement of ontacts I9 and 25. Preferablv a thin gasket 35 of paper or the like i inserted between ea h block !8 and the can v H! to cushion the compression ex d by bolt 35.

It will be noted in Fig. 2 that the upper face of contact 25 is arcuately formed about center 3! and this center lies substantially in the same horizontal plane as pivot 29. It results from this construction that quite a large variation in the vertical position of the mating contacts l9 and 25 may take place with only a small horizontal movement of contact 25 along its support-.

necessary lateral movement of contacts 25 at right angles to bolt 32.

What we claim is:

1. Lamp hanger electrical contact supporting means comprising bracket means, a contact support having recesses for receiving contact members, a pair of contact members mounted in spaced relation on said support in said recesses and laterally movable therein, there being a fixed portion of said bracket means adjacent the open ends of said recesses holding said contact members in said recesses, and pivot means operatively connecting said support to said bracket means and located between said contact members.

2. Lamp hanger electrical contact supporting means comprising bracket means, supporting means for said bracket means permitting the latter to oscillate about its central portion, contact supporting bars one on each side of the central portion of said bracket means, pivot means operatively connecting each of said supporting bars intermediate its ends to said bracket means, each of said bars being provided with recesses on opposite sides of its pivot means, a contact member in each of said recesses, and there being fixed portions of said bracket means adjacent the open ends of said recesses holding said contact members therein, whereby when engaging mating contacts the contact members on each bar may equalize .pressure about the associated pivot -means and the contact members on the two bars equalize pressure by oscillation of said bracket.

3. Lamp hanger electrical contact supporting means comprising bracket means having an opening therein, a contact support having spaced open-end recesses for receiving contact members, pivot means adjacent said opening connecting said support between said recesses with said bracket means, a contact member slidable into each recess at its open end only, and there being a fixed portion of said bracket means forming a part of the perimeter of said opening and positioned adjacent the open ends of said recesses for holding said contact members therein.

4. Lamp hanger electrical contact supporting means comprising bracket means, a contact support at one side of said bracket means, pivot means connecting said support intermediate its ends with said bracket means, there being recesses in said support one on each side of said pivot means, each recess opening at the side to ward said bracket means only, a contact mem-

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