Snap-in Type Lamp Bulb Socket

Abstract

A lamp socket normally used on automotive vehicles which is snapped into an opening in a panel for mounting featuring T-shaped spring retaining prongs projecting axially from the shell of the socket. Each prong has two knees depending from each side of the T-shaped prong which are axially spaced apart to provide improved socket retention in panels of varying thicknesses. A lock-in feature is also provided which allows the socket to be snapped into a keyed opening in a mounting panel, but which requires the socket to be indexed relative to the opening before the socket can be removed therefrom. The lamp-receiving shell includes an integrally formed grounding terminal adapted to be connected to an electrical ground for conducting electric current away from the lamp.

Description

This invention relates to lamp sockets and specifically to sockets of the type normally used on automotive vehicles which are snapped into an opening in a panel for mounting.

Lamp sockets of the snap-in type are frequently unable to accommodate mounting panels which vary substantially in thickness while still providing good retention characteristics. Generally these sockets feature spring mounting prongs cantilevered from the socket body and formed so as to provide a single knee which is designed to engage the edge of a panel opening. As the socket is inserted into the panel opening the prongs deflect until the knee extends beyond the inner surface of the panel, the spring characteristic of the prongs thereby retaining the socket in the mounting panel. If the mounting panel is too thin the socket is loosely retained, and if the panel is too thick the socket cannot be inserted so that the knee extends beyond the inner surface of the mounting panel. The removal of the snap-in socket from the mounting panel is accomplished by bodily pulling the socket out of the opening, which can be done regardless of the rotational orientation of the socket relative to the panel opening.

The usual construction of a snap-in type lamp socket comprises a body portion, or shell, crimped to a prong ring which carries the mounting prongs. In this arrangement the ground path for the electric current from the lamp bulb is through the shell and then through a terminal on the prong ring to a ground connection. Since the shell is crimped to the prong ring the resistance of this attachment contributes to the total resistance in the circuit, thereby reducing the electric efficiency. Furthermore, since the terminal is formed as a radial extension on the prong ring, the size of the blank from which the prong ring is formed is substantially larger than the diameter of the ring itself.

In the light socket assembly of the present invention the prong ring is crimped to the open upper end of the shell so that it extends radially outwardly therefrom and, thus, does not interfere with the insertion of a lamp bulb into the socket portion of the shell. The prong ring is fashioned with a plurality of spring members for snapping the assembly into engagement with an opening in a body panel. Each spring member is fashioned with a pair of spring fingers, some of which are specifically formed with axially spaced bends or knees to enable mounting the assembly in body panels of different thicknesses. The spring fingers of other spring members are circumferentially located relative to notches in the periphery of the panel opening to lock the assembly on the panel after it is inserted therein and rotated slightly.

The lower end of the shell is formed with an end wall having an opening therein to accommodate the end of the internal bulb contact block. The latter opening is so formed that a portion of the metal removed remains integrally connected to the shell and forms a blade which serves as a ground terminal which is in direct electrical contact with the shell.

It is an object of the present invention to provide a lamp socket of the snap-in type which provides improved retention to a mounting panel.

It is another object of this invention to provide a snap-in type lamp socket which can accommodate a range of thicknesses of mounting panels.

Still another object of this invention is the provision of a snap-in type lamp socket which must be rotated before it can be removed from the mounting panel so as to provide a lock-in feature.

Another important object of this invention is the provision of a ground terminal for a lamp socket which is formed integrally with the socket shell from material which is otherwise discarded.

In the drawings:

FIG. 1 is a front view of the lamp socket of the present invention mounted on a panel, with a portion broken away and a lamp bulb inserted in the socket.

FIG. 2 is an enlarged left-hand side elevational view of FIG. 1 with the lamp bulb removed from the lamp socket.

FIG. 3 is a view taken in the direction of arrow 3 in FIG. 2.

FIG. 4 is a side elevational view of the arrangement of FIG. 3.

FIG. 5 is a view taken in the direction of arrow 5 in FIG. 2.

FIG. 6 is a view taken in the direction of arrow 6 in FIG. 2.

FIG. 7 is a view taken in the direction of arrow 7 in FIG. 2.

FIG. 8 is a side elevational view of the arrangement shown in FIG. 7.

FIG. 9 is a view showing a portion of a mounting panel with a suitable opening for receiving the lamp socket of the present invention, the scale of the figure being slightly reduced from that of FIG. 2.

FIG. 10 is a fragmentary view of the bottom right-hand side of FIG. 1 illustrating the integrally formed grounding terminal.

FIG. 11 is a right-hand side elevational view of FIG. 1, but shown during the process of forming the grounding terminal.

Referring to FIG. 1, the lamp socket 12 of the present invention is shown having a dual filament lamp bulb 14 retained therein in the customary manner as at 16. Also referring to FIG. 2, socket 12 comprises a prong ring 18 having an annular prong base 19 and radially projecting tabs 20 to which is crimped a generally tubular shell 22 as at 23 so that shell 22 and prong ring 18 are substantially coaxial. The crimped flange portion 24 of shell 22 is radially disposed from the axis of shell 22 and forms an abutment which engages the outer surface 25 of a mounting panel 26 when socket 12 is retained in panel 26. A contact core, or block, 27 extends through an opening 28 in the base 29 of shell 22 and carries a contact arrangement 30 which feeds lamp 14 in the usual manner. Prongs 32, 34, 36, 38 and 40 project perpendicularly relative to base 19 and are adapted to retain socket 12 to mounting panel 26.

Prongs 32 and 38 are identical and are better shown in FIGS. 3 and 4. Each prong comprises a spring leaf 46 substantially T-shaped as shown in FIG. 3 and projecting upwardly relative to base 19. As leaf 46 extends from base 19 it has its lower portion inclined radially outwardly from the axis of shell 22 and then is bent so that its upper portion is inclined radially inwardly. Prong legs 42 and 44 depend from each side of the top of leaf 46 downwardly toward base 19. Leg 42 has a knee 48 axially spaced from crimp 24 while leg 44 has a knee 50 axially spaced from crimp 24 a distance less than the spacing of knee 48 from crimp 24.

Referring to FIGS. 5 and 6, prong 34 is shown to be generally similar to prongs 32 and 38 but has a shorter right-hand leg 52. Prong 36 is likewise similar to prongs 32 and 38 but has a shorter left-hand leg 54.

FIGS. 7 and 8 show the details of prong 40, which is significantly different from the other four prongs. Prong 40 comprises a support 56 adjacent one side of which a leg 58 is supported, and adjacent the opposite side of which a tab 60 is turned inwardly.

FIG. 9 shows a portion of mounting panel 26 which has a suitable opening 64 for receiving socket 12. Panel 26 is provided with a stop 66 having radially disposed sides 68 and 70 and extending arcuately about the center of opening 64 so as to project radially inwardly of the circumference of the opening. Notches 72, 74 and 76 are disposed around the periphery of opening 64 and extend radially outwardly of the circumference of the opening.

Referring to FIGS. 1 and 10, a grounding terminal 78 is integrally formed with shell 22. The way in which terminal 78 is formed can be better understood from FIG. 11. After shell 22 is drawn, the solid shell base 29 is blanked along the closed line 79 to form a scrap piece 77 which, when removed, defines terminal 78 and a portion of the elongated opening 28. Terminal 78 is turned outwardly perpendicular to base 22 to complete the definition of opening 28. Two curved notches 79' are provided at the ends of a bend line 75 along which terminal 78 is turned outwardly. As should be readily apparent, the length of terminal 78 is substantially equal to the width of opening 28. However, opening 28 may be formed as required to provide adequate length for terminal 78. For example, in the illustrated arrangement of FIG. 11, bend line 75 is offset radially outwardly of the adjacent lengthwise edge of opening 28 so that the length of the formed terminal 78 is slightly greater than the nominal width of opening 28. With terminal 78 turned outwardly, the elongate opening 28 can receive contact block 27. The outer edge 81 of terminal 78 is coined to the shape illustrated for telescopic interengagement with a grounded connecting terminal (not shown). Because terminal 78 is integrally formed with shell 22, the electrical circuit between lamp bulb 14 and ground does not depend upon the mechanical engagement of the shell and the prong ring, as is the case where the terminal is formed in the prong ring and the prong ring is mechanically attached to the shell.

The socket mounting aspect of this invention can be better appreciated by describing the installation of socket 12 in panel 26 and its subsequent removal therefrom. Socket 12 is preferably mounted on panel 26 by first rotationally orienting socket 12 so that stop 66 is interposed between prongs 32 and 40, with side 70 being more closely adjacent leg 42 of prong 32 than is side 68 of tab 60. Socket 12 is next bodily moved toward panel 26 so that prongs 32, 34, 36 and 38 by virtue of their engagement with the edge of opening 64 are deflected radially inwardly. When crimp 24 abuts the outer surface 25 of panel 26, socket 12 is retained on panel 26. With socket 12 retained as shown in FIG. 1, knees 48 of legs 42 of prongs 32, 36 and 38 retain the socket to the panel. If the mounting panel were thinner as indicated in FIG. 4, knees 50 of legs 44 of prongs 32, 34 and 38 would retain the socket. Thus, it will be appreciated that substantial variations in thickness of mounting panels may be accommodated by the particular arrangement of the knees relative to crimp 24.

Furthermore, the design of the prongs is such that the retention characteristics are substantially enhanced. Prong ring 18 is preferably formed of spring steel material and since the prongs are cantilevered on base 19, the upper end of leaf 46 is radially deflectable. By also cantilevering legs 42 and 44 from the deflectable end of leaf 46, this prong design provides a doubly resilient retaining prong which may be readily deflected to provide excellent socket retention in the mounting panel. This is true regardless of whether one or more legs are depended from spring leaf 46.

With socket 12 mounted in panel 26, legs 52, 54 and 58 project radially outwardly beyond the circumference of opening 64. This prevents socket 12 from being directly pulled out of opening 64 and provides a lock-in feature. In order to remove socket 12, it must first be rotated until tab 60 of prong 40 abuts side 68 of stop 66. In this condition, leg 52 of prong 34 registers with notch 72, while leg 54 of prong 36 registers with notch 74, and leg 58 of prong 40 registers with notch 76. Socket 12 may now be bodily pulled out of opening 64.

While the invention has been described with reference to the preferred installation and removal method, it will be understood that socket 12 may be inserted into opening 64 so long as stop 66 is interposed between prongs 32 and 40. For example, if socket 12 is inserted in opening 64, with legs 52, 54 and 58 registering with notches 72, 74 and 76 respectively, there is no need to rotate socket 12 to accomplish its removal from panel 62. Also, it should be apparent that a socket having the improved retention characteristics of the present invention may be designed to accommodate smaller or larger ranges of panel thicknesses by the number of prongs employed and the particular axial displacements of the prong knees 48, 50 relative to crimp 24.

Claims

I claim:

1. In a snap-in type lamp socket having a generally tubular shell adapted to receive a lamp bulb at one end thereof and a contact arrangement at the other end thereof for conducting electric current to said bulb, the combination with said shell comprising abutment means on said shell radially disposed from said shell axis and adapted to engage one surface of a socket mounting panel when said socket is inserted into an opening in said panel and a plurality of prongs circumferentially disposed about the axis of said shell and projecting generally axially relative to said shell, said prongs being adapted to be inserted into said opening, some of said prongs comprising a spring leaf extending substantially in said axial direction and having one end fixed on said shell and the other end radially deflectable in a cantilever fashion and a pair of spring legs cantilevered from the last-mentioned end of the spring leaf and extending generally axially toward the first-mentioned end of the spring leaf, said legs being radially deflectable and each having a knee axially spaced from said abutment means, one of said knees being spaced axially from said abutment means a distance greater than the other knee whereby, when said socket is inserted into said opening in said panel, said prongs are radially deflected to cause the panel to be retained between one set of said knees and the abutment means and, when the socket is inserted into an opening of a thicker panel, the prongs are radially deflected to cause the panels to be retained between the other set of knees and the abutment means.

2. The combination called for in claim 1 wherein the two spring legs on said spring leaf are located circumferentially adjacent said spring leaf and on opposite sides thereof.

3. The combination called for in claim 2 wherein said knees on said spring legs are equally radially spaced from the axis of the shell and the two spring legs terminate axially of said abutment means a distance less than the thickness of said first panel.