US3668763A

US3668763A - Wire strip and wrap bit

Info

Publication number: US3668763A
Application number: US34015A
Authority: US
Inventors: Percy Leonard Micklewright; Ernest Victor Scaddan
Original assignee: International Standard Electric Corp
Current assignee: STC PLC
Priority date: 1969-05-09
Filing date: 1970-05-04
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13
Also published as: DE2021548A1; CH523602A; ES379413A1; FR2047456A5; GB1251267A

Abstract

A wire-wrapping bit cuts and strips a wire end and wraps a terminal in one operation using ''''free'''' ends of insulated wire (that is, not intended to be drawn up tight). The cutting elements are removed, and an easy-feed wire hold guide and length gauge are provided, whereby wire may be fed through the guide up to a striker flange on the shank of the bit, for determining the skinner length and the wire held against withdrawal by being trapped in the skinner plate. A collar surrounding the feed guide assists the feed and permits wire to be fed at 45* to the bit and prevents ''''snatch.'''' An expanding bit shank, and a feed channel extending its length, both assist in ejection of the insulation after the wrapping operation.

Description

United States Patent 51 June'13, 1972 Micklewright et al.

[54] WIRE STRIP AND WRAP BIT [72] Inventors: Percy Leonard Mlcklewright, Sawbridgeworth; Ernest Victor Scaddan, London, both of England [21] Appl. No.: 34,015

[30] Foreign Application Priority Data May 9, 1969 Great Britain ..23,745/69 [5 2] U.S. Cl. ..29/203 DT [51] Int. Cl. ..HOSk 13/04 [58] Field of Search ..29/203 D, 203 DT, 628, 203 H, 29/203 R; 8 1/95 [56] References Cited UNITED STATES PATENTS 3,246,381 4/1966 Etchison, Jr. et a]. ..29/628 X Logan et al.. ..8l/9.5 X Dorsey ..29/203 H Primary Examiner-Thomas l-l. Eager Attorney-C. Cornell Remsen, Jr., Walter J. Baum, Paul W. Hemminger, Charles L. Johnson, Jr., Delbert P. Warner and James B. Raden [5 1 A ABSTRACT A wire-wrapping bit cuts and strips a wire end and wraps a terminal in one operation using free" ends of insulated wire (that is, not intended to be drawn up tight). The cutting elements are removed, and-an easy-feed wire hold guide and length gauge are provided, whereby wire may be fed through the guide up to a striker flange on the shank of the bit, for determining the skinner length and the wire held against withdrawal by being trapped in the skinner plate. A collar surrounding the feed guide assists the feed and permits wire to be fed at 45 to the bit and prevents "snatch." An expanding bit shank, and a feed channel extending its length, both assist in ejection of the insulation after the wrapping operation.

5 Claims, 3 Drawing Figures PATENTEDJUH 13 me P. L. Micklewright E. V. Scaddan W A ftorney This invention relates to wire wrapping devices, including bits for such devices, such as are used for making wrapped electrical connections particularly but not exclusively in telecommunications equipment; The bits are mounted in pneumatically or electrically operated guns.

Many prior art devices of this type are known, and the present applicants have described one in prior British specification No. 1,050,211 (L.T.Wood, T.G.Fisherl-l). According to this prior specification, there is provided a wirewrapping bit, which includes a hole at its front end which can receive a terminal towhich a wrapped connection is to be made, a first cutter also at said front end and fonned by a slot in a disc-like portion surroundingsaid hole, which slot is of such a size that when the bit is rotated with an insulated wire in it the insulation but not the wire is cut, and further cutter rear member 3, and an intermediate member 4. As shown in FIG. 3, an extension of the'front member 2 is concentric with and inside the rear member 3, in which it is a running fit,

. and the extension 5 is pinned to the D-section 1.

means between the ends of the bit, which further cutter means includes two adjacent discs one of which is rotatable with the bit while the other is not, one of said adjacent discs having an inwardly-extending slot and the other having a sector removed from its circumference, which further cutter means cuts bothinsulation and wire when an insulated wire is put in, wherein to wrap a wire to a terminal that terminal is fitted into said hole and the wire bent round the terminal and fitted into both cutters, whereafler the bit is rotated, causing the further cutter to cut the insulation and wire, and the first cutter to strip the insulation while the wire is wrapped on the temrinal,

In such a device all the free end of wire emerging from a cable form at a point where a terminal post is to be wrapped is pulled up tight, and the wire end cut to length and stripped by the wrapping operation. v

However, in certain equipment, a need arises for a somewhat different action, whereby only a predetermined length of the free end of wire emerging in the vicinity of the terminal post is engaged for the wrapping operation, so that the severing operation may be omitted, but ensuring that the selected length is held firmly in the end of the bit. The stripping and wrapping action then proceeds without further pull on the slack wire beyond the bit (avoidance of snatch.), and feed of the wire to the bit at an angle of about 45 is made possible.

According to the invention, there is provided a Wirewrapping bit adapted to strip a predetermined length of an insulated wire of specified core diameter and to 'wrap' the stripped wire around a terminal post of specified size: which comprises a rotatable-portion adapted to be driven through a relatively fixed portion by suitable driving means; wherein said rotatable portion is bored axially at its forward end to accept said specified size of terminal post, and comprises wire feeding, guiding and stripping means at its forward end to enable an insulated wire as aforesaid to be fed into a lengthwise channel on said rotatable portion for a predetermined distance as established by a flanged stopping member on said fixed portion, and thereafter to be restrained against withdrawal by locking in said stripping means; whereby on rotation of said rotatable portion in a predetermined direction, the insulation on such wire is severed at said strippingmeans, bare wire is caused to be withdrawn through said bit and wrapped around a terminal post within the end of said bit, and the insulation so severed and stripped is caused finally to be ejected from said bit. I

An embodiment of the present invention will now be described with reference to the accompanying drawing, in which F IG. 1 is an oblique view of a bit according tothe invention, FIG. 2 is an enlarged and exploded view of the front end of the bit in operation with a terminal post and wire in place just prior to wrapping, while FIG. 3 is an exploded view of the rear end of the bit.

The bit is intended for use with a wire-wrapping gun of wellknown type either electrically or pneumatically operated, and at its rear-end it has a D-section portion 1 which fits into the wrapping gun for engagement with the latters driving shaft. The bit includes three main members, a front member 2, a

The rear member 3-does not rotate when the bit is in use,

and has a keyway 6 into which fits a pin on the end of the wrapping gun. This pin keyway combination locks the rear member 3 against rotation. On its front end, the rear member 3 has a plane, disc-shaped flange 7 which abuts against a shoulder 8 raised on member 2, and mounted over flange 7 so as to encloseit is a partially cup-shaped member, the intermediate member 4, which is secured to member 3 by a setscrew 9 traversing a collar 10. As shown,.member 4 has a substantially quadrantal extension 1 lwhich partially encloses end 8 of member 2, and the function of member 4 is in the control of the length of wire stripped and wrapped, and ejection of the stripped insulation.

The front member 2, which rotates in use in a counter clockwise sense (viewed from its, end), as shown' by the arrow in FIGS. 1 and 2, ha a jaw assembly at itsfront end only, and a sloping enlarged portion towards its rear end, giving rise to the. shoulder 8 referred to previously. The jaw assembly is more complicated than the simple jaw member used'hitherto, and consists of a number of separate components, as revealed by the exploded view in FIG. 2. This figure shows, additionally, an insulated wire 12 threaded through the jaw members and taken up to the member 4, and a rectangulartag or terminal post 13 in position in the end bore of member 2 after traversing the jaw assembly.

Referring to FIG. 2, the jaw assembly consists of a collar member 14 into which is fitted a firstguide memberlS consisting of a disc with a carefully contoured aperture 16; this is followed by a second disc providing a hold-and-strip plate 17 having a champfered slot 25 with at least one shearing edge, the slot being adapted to accept a particular gauge of bare wire and to ensure the insulation on the wire being stripped at the edges; and the

parts

15 and 17 are secured to the end of member 2 by screws l8, 19 passed through the parts and lengthwise into the end, 15 and 17being oriented as shown with respect to a shallow flattened channel 20 milled in the end of member 2 and which opens out from the leading side of a narrow channel 21 extending lengthwise of member 2. Covering apart of the opened out channel 20 is a shaped segment '22, tapering towards the rear as regards the tunnel thereby fonned, and acting to provide a second guide member. The parts described for the, jaw assembly are preferably made in silver steel, tempered as required, and softsoldered after assembly to form a rigid structure. An axial hole '27 passes through the jaw members and into the end of 2 to enable the bit to be inserted over a'terminal post, as at 13.

The center line of the screw holes provided for the mounting screws l8, 19, in

members

15, 17 and 2 respectively acts conveniently as a fiduciary line in the shaping of these members, and thus in their ultimate mutual orientation on assembly. The center line in member 2 is parallel to the plane of the shallow channel 20 in this member. Adjacent hold-andstrip plate has its short slot at 25 made parallel to the center line, and thereafter opening out at 45 on the upper (trailing) edge, as shown, and tapering slightly at its lower (leading) edge, so as to provide an easy entry to the slot; the champfer earlier referred to is across the thickness of the plate for I providing the necessary shearing edge(s)..

The succeeding guide member 15 consists of a disc having a central hole for the terminal and a contoured aperture in one quadrant for permitting easy entry of a wire end, being coni toured generally with a bill" 24 on the trailing side having its inner edge straight and at an angle slightly less (10- l5) than a right-angle to the center line, and a radial contour at 26 on the leading side around the hole for screw 18. A shallow concentric recess 23 surrounds the central tag hole and is of a diameter to accommodate a turn of the bare wire being wrapped around the terminal post, so as to ensure the end of the wrapped wire being finished off neatly. The inner edge of bill" 24 is tangential to the outer circumference of this recess. Collar 14 surrounds member 15 thus providing a controlled easy entry for wire being fed to the bit, closing the aperture at the circumference, and permitting the wire fed in being angled back at about 45. It also prevents snatch of the wire,- experienced in previous wrapping tools.

The operation of the bit will now be described with particular reference to FIG. 2. A terminal tag or post 13 to which a length of wire is to be attached firmly by wrapping is inserted into the axial holes 27 in the jaw assembly and member 2, and the wire 12 is fed from the left or right (looking down the bit) into the assembly via the opening 16 in member 15. The wire traverses member 17 and enters the tunnel beneath member 22 on member 2 and is thereafter guided up the milled slot 21 to abut against flange 7 beneath extension 11 of member 4. The insulated wire is thus trapped in the slot of cutter 17 by means of the shearing edge and cannot be withdrawn (i.e. without stripping). The gun is then triggered or switched on. The rotation counter-clockwise of member 2 with the slack wire 12 being held tight causes the insulation on the wire, but not the wire itself, to be severed in slot 25 andthe wire core to be withdrawn through the severed sleeve and back through the jaw members, and to be wound tightly on the terminal post. a

In the operation just described, the rotation is such that the stripped wire is fed back through the bit clear of the stripping edge(s), and the bare wire is not therefore marked or scored.

Thus, the wire is gauged for length of wrap, desleeved and wrapped on a tag, and finally neatened off, in one single operation, and the sleeve readily ejected thereafter, without damage to the wire itself.

it may be noted that the guide member 15 with its surrounding collar .14 are made as separate parts for ease of tooling, being thereafter soft soldered to a unit, but could be made from one disc in the first place; that the segment 22 could be made integral with the member 2 if preferred (ease of tooling apart); and that the member 4, provided as a separate member attached to member 3, could be made integral with member 3. However, member 3 is preferably made of silver steel, while member 4 need not be of other than aluminum or light alloy material, and is in any case more economically made as a separate item in view of its diameter.

We claim:

1. A wire-wrapping bit comprising an elongated rotatable portion and a stationary portion concentric with part of said rotatable portion for supporting said rotatable portion while permitting relative rotational motion between said portions, said rotatable portion having at a first end thereof a jaw member fixed to said rotatable portion, said jaw member having a centrally located axial aperture for receiving the end of a terminal post about which wire is to be wrapped, said jaw member also having an enclosed substantially quadrantal feed aperture, a narrow stripping aperture and a guiding channel extending into a lengthwise channel of said rotatable portion, at least one edge of said stripping aperture being sharpened to permit the stripping of insulation from said wire as said wire is to be wrapped about said terminal post, said quadrantal feed aperture being so contoured and oriented with respect to said strippingaperture and said guiding channel that wire may be fed into said bit at an angle of approximately 45 backwards from said bit, said rotatable portion extending through said stationary portion and having at the second end of said rotatable portion a shaped terminus for plied to said rotatable portion,

allowing torque to be apsaid stationary portion having tion a flanged and partially cowled member enclosing said rotatable portion for determining the length of wire to be fed through said jaw member, said predetermined length being thereafter locked against withdrawal back through said stripping aperture, and rotation of said rotatable member causing stripped wire to be fed back through said jaw member and wrapped around said terminal post.

2. A wire wrapping bit which comprises a cylindrical bit portion rotatable within a relatively fixed portion and adapted to be rotated from its rearward end, and carrying at its forward end a jaw assembly consisting of an enclosed wire feed guide means and a wire hold and strip plate, together with further guide means in the surface of said cylindrical bit portion so orientated with respect to one another than an insulated wire of suitable core size for said bit fed forward-to-rearward into said bit will be trapped by said plate and restrained against withdrawal; said fixed portion carrying at its forward end a flanged member arranged to act as a stop to wire fed into said bit and along said further guide means so as to determine the length of wire to be wrapped; said rotatable portion withsaid jaw assembly being bored axially to accept a terminal of predetermined size around which a wrapped connection is to be made; whereby on feeding an insulated wire as aforesaid into said bit and up to said stop and centering said bit over a terminal to be wrapped and thereafter causing said bit to be rotated, the insulation on the wire fed into said bit is severed at said strip plate and the wire is withdrawn from said bit as a bare wire and wrapped around said terminal, and the severed insulation thereafter ejected from said bit.

3. A wire-wrapping bit as claimed in claim- 2 wherein said further guidemeans in the surface of said cylindrical bit portion comprises a narrow channel cut in the surface of said portion above said axial borehole and extending substantially the length of said cylindrical portion 'up to said flanged stop member, but widening out on its leading edge towards said jaw assembly to provide an entry therefrom, said widened out por-' tion being covered for part at least of the entry by a curved member tapering internally towards the narrower part of the channel so as to guide wire easily into this channel, said rotatable portion being enlarged slopingly towards said stop member.

4. A wire-wrapping bit as claimed in claim 2, wherein said wire hold and strip plate consists of a disc having an axial hole for said terminal and a slot cut across the disc with a shearing edge on the rearward surface of said disc adjacent said cylindrical bit portion, said slot being of a width to accept the core wire of an insulated wire as aforesaid and thereafter widening out towards the leading edge of said disc.

5. A wire-wrapping bit as claimed in claim 2, wherein said wire feed guide means consists of a disc having a central hole and a contoured aperture in one quadrant, a recess around said central hole on the forward side of said disc for accommodating a turn of wire when wrapped around a terminal, said recess merging into said aperture to form a straight edge at the trailing side of said aperture and tangential to said recess, the leading edge of said aperture being curved in a radial direction, and said perture being closed at the circumference.

Claims

1. A wire-wrapping bit comprising an elongated rotatable portion and a stationary portion concentric with part of said rotatable portion for supporting said rotatable portion while permitting relative rotational motion between said portions, said rotatable portion having at a first end thereof a jaw member fixed to said rotatable portion, said jaw member having a centrally located axial aperture for receiving the end of a terminal post about which wire is to be wrapped, said jaw member also having an enclosed substantially quadrantal feed aperture, a narrow stripping aperture and a guiding channel extending into a lengthwise channel of said rotatable portion, at least one edge of said stripping aperture being sharpened to permit the stripping of insulation from said wire as said wire is to be wrapped about said terminal post, said quadrantal feed aperture being so contoured and oriented with respect to said stripping aperture and said guiding channel that wire may be fed into said bit at an angle of approximately 45* backwards from said bit, said rotatable portion extending through said stationary portion and having at the second end of said rotatable portion a shaped terminus for allowing torque to be applied to said rotatable portion, said stationary portion having intermediate said first and second ends of said rotatable portion a flanged and partially cowled member enclosing said rotatable portion for determining the length of wire to be fed through said jaw member, said predetermined length being thereafter locked against withdrawal back through said stripping aperture, and rotation of said rotatable member causing stripped wire to be fed back through said jaw member and wrapped around said terminal post.

2. A wire wrapping bit which comprises a cylindrical bit portion rotatable within a relatively fixed portion and adapted to be rotated from its rearward end, and carrying at its forward end a jaw assembly consisting of an enclosed wire feed guide means and a wire hold and strip plate, together with further guide means in the surface of said cylindrical bit portion so orientated with respect to one another than an insulated wire of suitable core size for said bit fed forward-to-rearward into said bit will be trapped by said plate and restrained against withdrawal; said fixed portion carrying at its forward end a flanged member arranged to act as a stop to wire fed into said bit and along said further guide means so as to determine the length of wire to be wrapped; said rotatable portion with said jaw assembly being bored axially to accept a terminal of predetermined size around which a wrapped connection is to be made; whereby on feeding an insulated wire as aforesaid into said bit and up to said stop and centering said bit over a terminal to be wrapped and thereafter causing said bit to be rotated, the insulation on the wire fed into said bit is severed at said strip plate and the wire is withdrawn from said bit as a bare wire and wrapped around said terminal, and the severed insulation thereafter ejected from said bit.

3. A wire-wrapping bit as claimed in claim 2 wherein said further guide means in the surface of said cylindrical bit portion comprises a narrow channel cut in the surface of said portion above said axial borehole and extending substantially the length of said cylindrical portion up to said flanged stop member, but widening ouT on its leading edge towards said jaw assembly to provide an entry therefrom, said widened out portion being covered for part at least of the entry by a curved member tapering internally towards the narrower part of the channel so as to guide wire easily into this channel, said rotatable portion being enlarged slopingly towards said stop member.

5. A wire-wrapping bit as claimed in claim 2, wherein said wire feed guide means consists of a disc having a central hole and a contoured aperture in one quadrant, a recess around said central hole on the forward side of said disc for accommodating a turn of wire when wrapped around a terminal, said recess merging into said aperture to form a straight edge at the trailing side of said aperture and tangential to said recess, the leading edge of said aperture being curved in a radial direction, and said aperture being closed at the circumference.