US3871738A - Fuse contacts - Google Patents

Abstract

An electrical contact for a cartridge fuse, the contact being stamped and formed from resilient sheet metal and comprising two superimposed strips forming a composite leg having a mounting foot at one end, in which the mounting foot has a surface facing generally away from the contact portion for engagement with an upper surface of a mounting board, and an axis of a cone of the contact converging with the plane in which the surface of the mounting foot is disposed at a location spaced from a side of the contact at which the end portions are located.

Description

iinitet e States Dechelette 1 Mar. 18, 1975 1 FUSE CONTACTS [75] Inventor: Helen Dechelette, Saint Cloud,

France [73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: Nov. 29, 1973 [21] Appl. No.: 420,181

[30] Foreign Application Priority Data Dec. 14, 1972 France 72.44595 [52] US. Cl. 339/256 C, 339/17 D, 339/52 R, 339/65, 339/150 F, 339/219 F, 339/252 F,

[51] Int. Cl. ..1-ll051 1/04 [58] Field of Search... 339/17 R, 17 C, 17 D, 50 R, 339/50 L, 50 S, 51, 52 R, 52 S, 56, 65, 66,

66 T, 93 R, 93 L, 95 R, 95 T, 119 L, 120,

125,150 F, 219 F, 252 F, 253 F, 256 R, 256

C, 258 R, 258 S, 258 P, 258 F, 262 R, 262 F,

[56] References Cited UNITED STATES PATENTS 2,338,835 l/l944 Bryant 339/52 R 2,621,227 12/1952 McMahon 339/219 F 3,348,189 10/1967 Coldren et a1. 339/32 R 3,360,765 l2/l967 Strange et a1. 339/50 R Primary ExaminerRoy D. Frazier Assistant E.ramt'ner-Terre1l P. Lewis Attorney, Agent, or Firm-William J. Keating; Jay L. Seitchik; Frederick W. Raring [57] ABSTRACT An electrical contact for a cartridge fuse, the contact being stamped and formed from resilient sheet metal and comprising two superimposed strips forming a composite leg having a mounting foot at one end, in which the mounting foot has a surface facing generally away from the contact portion for engagement with an upper surface of a mounting board, and an axis of a cone of the contact converging with the plane in which the surface of the mounting foot is disposed at a location spaced from a side of the contact at which the end portions are located.

4 Claims, 4 Drawing Figures FUSE CONTACTS This invention relates to a contact for a cartridge fuse having conical end caps formed from electrically conductive metal.

The present invention is a unitary electrical contact for a cartridge fuse having conical conductive ends, the contact being stamped and formed from resilient sheet metal and comprising two superposed strips forming a composite leg having the mounting foot at one end, the strips being bent apart at the other end and being integrally joined at the other end by a U channel receptacle having two spaced walls joined by a bight, the channel extending generally along the axis of the composite leg with the walls located in planes generally parallel to the plane of the composite leg, each channel wall being bent at an end portion remote from the bight away from the other wall into the form of a part surface of a cone the apex of which is located between the bight and the end portions and the axis of which extends from the apex away from the bight and between the channel walls, the two part-conical surfaces forming a contact portion.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of two contacts according to the invention, a cartridge fuse and a printed circuit board prior to assembly of the various components;

FIG. 2 is a view looking in the direction of arrow A in FIG. 1, of one of the contacts of- FIG. I mounted on the printed circuit board;

FIG. 3 is a view looking in the direction of the arrow B in FIG. 1 of the two contacts of FIG. I mounted on the printed circuit board prior to full insertion ofa fuse; and

FIG. 4 is a view similar to FIG. 3 but showing the contacts after full insertion of the fuse.

Each contact is stamped from resilient sheet metal and then bent into the form shown. A central portion comprises two superposedstrips 11 forming acomposite leg 12. Thestrips 11 are bent apart at the upper end of the composite leg to form two halves ofastop 13 the purpose of which is explained below. Thestrips 11 are integrally joined at the upper end by aU channel receptacle 15 having twospaced walls 16 joined by abight 17, the channel extending generally along the axis of theleg 12 with thewalls 16 located in planes generally parallel to the plane of theleg 12. Thefree end portion 19 of eachchannel wall 16 is bent away from the other wall at 20 into the form of a part surface of a cone the apex of which is located between thebight 17 and thefree ends 19 of thechannel walls 16 and theaxis 21 of which extends from the apex away from thebight 17 and generally parallel to and between thewalls 16. The two part-conical surfaces 20 define together with the stop 13 a contact portion for receiving an end cap of a fuse as described below. Thefree ends 19 of thechannel walls 16 are bent away from each other at portions 22 remote from theleg 12 to form a flared mouth best seen in FIG. 2.

Thestrips 11 are bent apart at 23 the lower end of theleg 12 and are integrally joined at the lower end by aU channel 24 generally aligned with thereceptacle 15. Thechannel 24 has abight 25 joining twospaced walls 26 which havefree ends 27 projecting laterally beyond theleg 12. The free lower ends of thestrips 11 are formed as spacedtabs 28 extending in directions parallel to theleg 12.

To mount a pair ofcontacts 10 on a printedcircuit board 29 two pairs of spaced throughholes 30 are provided in the printed circuit board. Eachcontact 10 is applied to theupper surface 31 of theboard 29 with its twotabs 28 received throughrespective holes 30 and with thelower edge 32 of theU channel 24 hard against theupper surface 31 as shown most clearly in FIGS. 3 and 4. Thetabs 28 are then bent upwardly and towards each other against thelower surface 33 of the board as shown in FIG. 2 after which the tabs are soldered as shown at 34 to conductors on thelower surface 33. As

shown in FIG. 3 theaxes 21 about which thepartconical surfaces 20 are generated converge between the twocontacts 10 in a direction towards theboard 29.. This is brought about because thelower edge 32 of theU channel 24 of each contact .10 is in a plane which converges with theaxis 21 of the associated partconical surfaces 20 at the side of the contact at which thereceptacle 15 opens into.

FIG. 1 shows a conventional form ofcartridge fuse 35 which is formed with aninsulating body 36 and two conicalconductive ends 37 joined. together by a fusibleconductive strip 38.

Insertion of thefuse 35 into thereceptacles 15 of the pair ofcontacts 10 will now be described. Thefuse 35 is inclined with oneend 37 nearer theboard 28 than the other, and the oneend 37 is introduced into areceptacle 15. In order to insert theother end 37 of thefuse 15 in theother contact 10, the other end 37 (the right-hand end as seen in FIG. 3) is forced towards the board into the flared mouth of thereceptacle 15 of the right-hand contact 10, and thechannel walls 16 flex apart allowing theother end 37 to snap into engagement with the part-conical surfaces 20 and theroof 13. As theother end 37 is being forced into position thereceptacles 15 of the twocontacts 10 are forced apart by flexure of each contact about theparts 23 and 13 joining theU channel 24 and thereceptacle 15, respectively, to theleg 12 to take up the position shown in FIG. 4 on full insertion of thefuse 35. In this position the twoconical axes 21 and the fuse axis are aligned parallel to theboard 29. Thus theconical ends 37 are perfectly seated in the respective receptacles and the outward flexure of the contacts ensures a strong contact force and pull-out force.

In practice the receptacles may be manufactured in strip form and applied by automatic insertion tooling to the printed circuit boards.

What is claimed is:

1. A unitary electrical contact for a cartridge fuse having conical conductive ends, the contact being stamped and formed from resilient sheet metal and comprising two superposed strips having a contiguous portion forming a composite leg disposed in a first plane and having a mounting foot at one end, the strips being bent apart at the other end and being integrally joined at the other end by a U channel receptacle having two spaced walls joined by a bight, the channel extending generally along the axis of the composite leg with the walls located in second and third planes generally parallel to the first plane, each channel wall being bent at an end portion remote from the bight away from the other wall into the form of a part surface of a cone the apex of which is located between the bight and the end portions and the axis of which extends from the apex away from the bight and between the channel walls, the two part-conical surfaces forming a contact portion.

2. A contact according to claim 1, in which the mounting foot has a surface disposed in a fourth plane perpendicular to the first plane, the surface facing generally away from the contact portion for engagement with the upper surface of a mounting board, and the axis of the cone converges with the fourth plane in which the surface of the mounting foot is disposed at a location spaced from a side of the contact at which the end portions are located.

joining two spaced walls which have free ends projecting laterally beyond the composite leg, the free ends of the strips being formed as spaced tabs extending parallel to the composite leg.

Claims (4)

1. A unitary electrical contact for a cartridge fuse having conical conductive ends, the contact being stamped and formed from resilient sheet metal and comprising two superposed strips having a contiguous portion forming a composite leg disposed in a first plane and having a mounting foot at one end, the strips being bent apart at the other end and being integrally joined at the other end by a U channel receptacle having two spaced walls joined by a bight, the channel extending generally along the axis of the composite leg with the walls located in second and third planes generally parallel to the first plane, each channel wall being bent at an end portion remote from the bight away from the other wall into the form of a part surface of a cone the apex of which is located between the bight and the end portions and the axis of which extends from the apex away from the bight and between the channel walls, the two part-conical surfaces forming a contact portion.

2. A contact according to claim 1, in which the mounting foot has a surface disposed in a fourth plane perpendicular to the first plane, the surface facing generally away from the contact portion for engagement with the upper surface of a mounting board, and the axis of the cone converges with the fourth plane in which the surface of the mounting foot is disposed at a location spaced from a side of the contact at which the end portions are located.

3. A contact according to claim 1, in which the end portions of the channel walls are bent away from each other at portions remote from the leg to form a flared mouth.

4. A contact according to claim 1, in which the strips are bent apart at the one end by a U channel generally aligned with the receptacle, the channel having a bight joining two spaced walls which have free ends projecting laterally beyond the composite leg, the free ends of the strips being formed as spaced tabs extending parallel to the composite leg.

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