US2946038A - Terminal lug for wire wound resistor - Google Patents

Description

July 19, 1960 c. JASIK ETAL 2,946,038

TERMINAL LUG FOR WIRE WOUND RESISTOR Filed Sept. 19, 1956 United States Patent .0

TERMINAL LUG FOR WIRE WOUND RESISTOR Filed Sept. 19, 19 56, Ser. No. 610,796 4 Claims. or. 339-217 This invention relates to a wire Wound electrical component and more particularly to conductor terminals therefor. Specifically, the present invention is primarily concerned with a novel conductor terminal construction for a wire-wound resistor.

The general organization of a wire-wound resistor comprises a plastic or ceramic spool or bobbin on which wire is wound in length to determine the value of the resistor. The resistor may then be coated or encapsulated with an insulating material. Before such insulation is applied, however, the bobbin is provided at its ends with some form of metallic lug to which the respective wire ends are fastened or soldered and which lugs serve to make connection to other components of the circuit in which the resistor is used.

It is an object of the present invention to provide a bobbin and co-acting terminals or soldering lugs which are readily and cheaply manufactured in mass production by an ordinary stamping mill.

It is another object of the invention to provide a connecting lug which requires no particular tools for assembling on bobbin ends and which is devised to snap into locking engagement with the bobbin.

It is a further object of the invention to provide a soldering lug which effectively grips the bobbin and is removable therefrom for replacement if necessary.

. The objects of the invention are brought about by means of a lug constructed of resilient sheet metal material and formed as a yoke having a pair of legs which fit into a groove disposed at a bobbin end, and being provided with ears that snap into indentations where the legs are forced into the groove. The terminal or lug is also provided with a pair of small ears to either of which the end of a resistance winding may be soldered.

A detailed description of the invention is now given in conjunction with the appended drawing, in which:

Figure 1 is an exploded end view showing a terminal in position above a bobbin and about to be moved into gripping engagement therewith.

Figure 2 shows a cross-section of the bobbin showing the terminal with the legs of the yoke slightly spread as they come into engagement with the bobbin and just prior to being snapped into place thereon.

Figure 3 shows an end view wherein the terminal is fully engaged with the bobbin.

Figure 4 is a perspective showing a bobbin with two terminals snapped into place and. in position to have the wire Winding of the bobbin soldered thereto.

Referring now to the drawing, the invention comprises a molded plastic bobbin body having an end portion 12 at each end set off by a groove 14 for accommodating the legs 18 of a terminal conductor or soldering lug 20. The free end of each leg 18 is provided with an car 24 terminating in a shoulder 26 which shoulder grips against respective shoulders 30 effected by radial slots 32 in the end portions 12 and which slots 32 extend into the surface of the bottom 33 of the groove. Thus, as viewed in Figure 2, the legs 18 have been 2 V forced apart from the dotted position to the spread position as shown in the full lines, the ears 24 riding against the bottom 33 of the groove 14 just prior to being moved into the slots 32. It will be understood by comparing Figure 2 with Figure 3 that further downward movement of the terminal 20 results in ears 24 sliding past the outer edges of the respective shoulders 30 and snapping into place in the slots 32, at which time the shoulders 26 ,are below and in engagement with respective shoulders 30.

In order to provide suitable resiliency for sidewise' movement of the legs 18, the body of the terminal 20 is provided with a slot 36, the sides of of the slot emerging from the body to form the legs 18. Thus, lengthened leverage is provided so that stress on the legs 18 tending to force the legs apart is not sufliciently great to make the terminal diflicult to snap into locked condition in the groove 14. When the terminal has been snapped into place it will be apparent that the arcuate inner edges 34 of the legs 18 substantially conform with the circular periphery of the bottom 33 of the groove to form a compact and snug fit thereagainst, although actual engagement is not essential.

Preferably, the thickness of the material from which the terminal is stamped should be such as to effect an easy but not wobby fit in groove 14.

Extending laterally outward from each car 24 is a small soldering lug 40 to either of which the end of a wire wound resistor accommodated in the recesses 44 of the bobbin, may be soldered in a well known manner.

For convenience in fabricating the bobbin, the slots 50 of the bobbin partitions 52 are in alignment with the slots 32. Slots 50 are required to conduct the wire leads outwardly of the windings in a well known manner.

It will be noted from the above description that the invention effects a completely symmetrical terminal lug which may be snapped into place on the end of a bobbin without orienting the lug in any particular position as to left or right, it being only required that the lug be pushed into the groove and thence rotated until the cars 24 snap into place in the'respective grooves 32. Alternately, the lug 20 may be simply juxtapositioned with respect to the bobbin 10 as shown in Figure 1 and pushed directly into the groove, in which case there would be no need to rotate the lug to bring about the ear and slot engagement.

Since all portions of lug 20 lie in the same plane it can be said that lug 20 is a fiat member.

Having thus described our invention, we are aware that changes may be made without departing from the spirit thereof and accordingly we do not seek to be limited to the precise illustration herein given except as set forth in the appended claims.

We claim:

1. In a wire wound resistor, a bobbin, a terminal element comprising a yoke having resilient relatively movable legs, said bobbin having a formation engageable by said legs wherein said legs grip said bobbin by virtue of their resilience, said legs being provided with shoulders lockingly cngageable with said formation, said formation comprising a peripheral groove formed in the material of said bobbin, said legs when being so engaged substantially conforming to said peripheral groove; said formation further comprising at least one radial slot ex tending longitudinally from an end of said bobbin to said groove, a wall of said slot forming a shoulder lockingly engageable by the shoulder of one of said legs.

2. In a wire wound resistor as set forth in claim 1', said formation further including another slot diametrically spaced from said first mentioned slot and having a wall forming a shoulder to lockingly engage with the shoulder of the other of said legs.

3; In awire wound resistor as set forth in claim 1, saidone leg having a'projection for soldering an end of"'Wire'woi1nd on'said bobbin, said projeetion being disposed in registration with said slot so as to be accessible therethrough. v

"4.? In awire" Wound resistor, a plastic bobbin having a'"peripheral' groove provided with shoulders iiidented 'in the bottom thereof, a terminal element including a'p'air ofre'sili'ent legs arcua'tely disposed to dorm a yoke slidable into said groove and adaptedto be' dive'rged'fby 10 forced engagement with the bottom of said groove, said legs being arranged in anarc having an internal shape snbst-antially' conforming to that of the bottom'of said groove so as to"straddle a portion thereof, and" projections carried by said legs for lockingly engaging" said 15 2,685,016

' 4 shoulderswhen said" legs are disposed 1 in- "said" groove; said terminal also including a stem joining said pair of =l'egs,"a slbtextending from the'points of juncture" of said legs With said stem for only a portion of the length 5 of said stem.

References Cited in the file of this patent UNITED STATES PATENTS 2,158,969 -O1iver a- -May 16,1939 2 ,533,483 Losquad-ro Dec. 12, 1950 2,636,067 Kraft Apr. 21', 1953 2,667,624 Bels Jan. 26, 1954 Blaekburn J uly 27, 1954

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