GB1601685A - Wire wrap bit - Google Patents

Description

(54) WIRE WRAP BIT (71) We, STANDARD TELEPHONES AND CABLES LIMITED, a British Company of 190 Strand, London W.C.2, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a wire stripping and wrapping tool.

Our UK patent 1 052480 describes such a cut and strip wire wrapping tool which enables an operator to apply an insulated wire to a terminal using the wire wrap technique. A disadvantage we have experienced lies in the use of modern plastics insulations on wire which is stronger than the materials in use around the time when the above patent was taken out. This causes the stripping action of the tool to be unreliable.

US patent 2765 684 discloses a wire stripping and wrapping tool in which two cutting jaws mate with each other to completely sever the insulation. This is a bulky tool which is very expensive to manufacture.

According to the present invention there is provided a wire stripping and wrapping tool comprising a first part having a bight for locating an insulated wire laid in it, a second part constrained to slide adjacent the first part backwards and forwards past the bight, there being an elongate space extending between the parts from adjacent the bight in the direction of relative movement for accommodating the insulation, there being a blade mounted on the second part transversely of the space and defining with the first part an aperture smaller than the insulated wire, whereby with a wire in the bight relative movement between the parts will cause the wire insulation to be caught on the edge of the bight and cut on one side by the blade as the blade advances past the bight, continued relative movement causing the insulation to tear at the other side, the tool having an aperture at its end which fits over a terminal to be wrapped, whereupon the parts can be rotated to cause the wire to be wrapped around the terminal and simultaneously stripped of its insulation.

In order that the invention can be clearly understood reference will now be made to the accompanying drawings, in which: Fig. 1 shows in perspective the end portion only of a side loading stripping and wrapping tool according to an embodiment of the invention, Fig. 2 shows part of the tool of Fig. 1 on an enlarged scale and Fig. 2A shows alternative forms of blade for the part shown in Fig. 2, Fig. 3 is an end view of the tool shown in Fig. 1 and Figs. 4, 5 and 6 are cross-sectional views on an enlarged scale of the end of the tool at three stages of stripping an insulated wire and wrapping it on a terminal.

Referring now to Fig. 1 (which is somewhat schematic) the tool is constructed of three main components, a first part consisting of the inner wrapping bit 1 carrying a replaceable blade 2, and a second part formed by an outer sleeve 3. The wrapping bit 1 can slide axially within the bore of the sleeve 3. The sleeve has a bight 4 formed in an opening 5 and aligned with a slot 6 in the sleeve 3 and an elongate space formed by a groove 7 which extends axially, between the sleeve and the bit, on the surface of the bit 1 and is also aligned with the bight 4 and the slot 6.

The wrapping bit 1 has a blind hole 8 in its end for accommodating a terminal to be wrapped with wire. The other side of the sleeve 3 has an axially-extending slot 9 which communicates with the opening 5.

As can be seen in Fig. 2 on a larger scale the inner wrapping bit 1 carries the blade 2 in a slot such as 10 or 11 transversely of and at right angles to the groove 7. The blade shown in Fig. 2 has a V-shaped cutting edge 12 and the broken lines indicate how it can be slid into and out of the slot 10. It could alternatively be fitted in the adjacent slot 11. This choice of positions enables the operator to select the length of wire which is to be stripped. The blade will strip more insulation off the wire in slot 10 than it will in slot 11. In wrapping the wire the result is that the first turn or so around the terminal to be wrapped will have insulation on it. This is discussed more fully later.

Fig. 2A shows alternative forms of blade, one blade 2a having a rectangular cutting edge 12a and another blade 2b having a U-shaped cutting edge 12b. The blades we have used are made of hardened spring steel about 5 thou thick. With thin insulation, of the order of 8 thou thick the blade may not require sharpening but with thicker insulation such as 14 thou and more, the blade works better if it is sharpened. For blades with parallel-sided cutting edges we find the clearance between the edges and the wire should be about 2 thou.

Fig. 3 is an end view of the tool of Fig.

1 on an enlarged scale.

In assembling the tool the cutter blade 2 is placed into its slot (10 or 11) in the inner wrapping bit 1, and the outer sleeve 3 is positioned over the inner wrapping bit so that its axial slot 6 is in line with the axial groove 7 in the surface of the inner wrapping bit. The assembly is fixed together (e.g. by a pin - not shown) so that no rotation between the outer sleeve and the inner wrapping bit can take place, but the outer sleeve can slide axially over the inner wrapping bit so that in the closed position of the tool the ends of the inner wrapping bit and the outer sleeve are in line, and the outer sleeve can move forward of the inner wrapping bit sufficient for the slot 9 and opening 5 in the outer sleeve to lie in front of the end of the inner wrapping bit.

Referring now to Figs. 4, 5 and 6, particularly Fig. 4, when the outer sleeve is in its open position an insulated wire 13 is placed in the bight 4 in the opening 5 and lies also on the lower edge of the slot 9.

The wire lies at 90" to the main body of the tool with sufficient wire extending beyond the tool to enable it to complete a desired number of wraps around a terminal.

Referring now to Fig. 5 the sleeve 3 has moved to its closed position a nose just forward of blade 2 bends the wire 13 and the bight 4 at the end of the slot 6 "wipes" the wire into the groove 7 in the inner wrapping bit and also pushes the conductor of the wire into the cutting blade. When the bight 4 in the outer sleeve is in line with the blade 2 only the conductor 14 of the wire 13 has sufficient room to be pushed into the cutter blade 2. Therefore, the insulation at the bight is forced beyond the bottom of the V-shaped cutting edge so that the insulation is cut. As seen in Fig. 5 the insulation 15 above the cutter blade builds up in front of the groove 7 until the insulation must shear under the force of the outer sleeve 3 closing. When the insulation has sheared the outer sleeve 3 continues until the closed position is reached and a gap is produced in the insulation of the wire, and the wire to be wrapped plus the insulation 1 Sa which is to be discarded lies in the slot 6 in the outer sleeve.

As shown in Fig. 6 the tool is then placed over a terminal 16 to which the wire is to be connected. The wire 13 is held while the outer sleeve and inner wrapping bit are rotated together by a motor (not shown).

This rotary motion wraps that portion of the wire 13 having the insulation 15 on it around the terminal for the first turn and this is followed by the stripped wire 14, the insulation lSa being removed as the wire is drawn down to be wrapped. When the wrap is complete the discarded piece of insulation l5a falls out of the slot 6 in the outer sleeve. When the wrap is complete the tool is removed from the terminal 16 and the outer sleeve returned to its open position for the cycle to be repeated.

As can be seen the cutter blade 2 and 2a is a replaceable item, to be inserted into the inner wrapping bit. It contains a slot or cutting edge 12, 12a or 12b of sufficient width and depth to allow only the conductor diameter of the wire into it.

The outer sleeve 3 is a metal tube with an internal diameter sufficiently large enough to allow the inner wrapping bit 1 to slide smoothly within it. At one end of the tube lies the opening 5 at right angles to the tube major axis and wide enough to allow the overall wire diameter including insulation into it so that when the wire is at the bottom of the slot 5, i.e. in the bight 4, the centre of the wire lies substantially on and across the centre of the outer sleeve.

The slot 6 is wide enough for the wire diameter including insulation to enter it and meet the tube's inner diameter and coincides with the groove 7 but does not continue to the end of the outer sleeve.

As can be seen in Fig. 6 the amount of insulation which is wrapped onto the terminal post, if any, is dependent on the position of the cutter blade 2 and therefore if the cutter blade 2 is positioned in the slot 11 shown in Fig. 2, then a second turn of the wire 13 with insulation such as 15 would occur on the terminal post. This initial turn 15 with insulation is not essential but helps to prevent the wire being unduly strained when it initially engages the edge of the terminal 16. The terminal % has an angular cross section, such as square or rectangular with relatively sharp edges and these edges bite into the turns 14 of the wire so as to provide good electrical connection.

Clearly it can be seen that the replaceable cutting blade offers the advantage that the tool does not have to be dispensed with when the first blade has become blunt. All that is required is for a new blade to be inserted and the outer sleeve replaced on the inner wrapping bit. The outer sleeve serves to hold the blade in position in the slot during operation.

It may not be necessary to have a groove such as 7 which accommodates the insulated wire. For example the groove could be replaced by a flat on the inner part.

WHAT WE CLAIM IS: 1. A wire stripping and wrapping tool comprising a first part having a bight for locating an insulated wire laid in it, a second part constrained to slide adjacent the first part backwards and forwards past the bight, there being an elongate space extending between the parts from adjacent the bight in the direction of relative movement for accommodating the insulation, there being a blade mounted on the second part transversely of the space and defining with the first part an aperture smaller than the insulated wire, whereby with a wire in the bight relative movement between the parts will cause the wire insulation to be caught on the edge of the bight and cut on one side by the blade as the blade advances past the bight, continued relative movement causing the insulation to tear at the other side, the tool having an aperture at its end which fits over a terminal to be wrapped, whereupon the parts can be rotated to cause the wire to be wrapped around the terminal and simultaneously stripped of its insulation.

2. A tool as claimed in claim 1, wherein the blade is removably mounted in a slot so as to be replaceable.

3. A tool as claimed in claim 2, comprising at least two such slots, axially spaced from one another, whereby the length of insulation to be stripped can be altered, as desired.

4. A tool as claimed in any preceding claim, wherein the first part comprises a sleeve having a transverse opening and the bight at the bottom of the opening, the second part comprising a rod which can slide axially in the sleeve, the rod having a flat or groove in it to form the space.

5. A tool as claimed in any preceding claim wherein the blade has a V-shaped cutting edge.

6. A tool as claimed in any preceding claim, wherein the second part has a nose just forward of the blade and which serves to bend a wire lying in the bight before the blade cuts the insulation.

7. A wire stripping and wrapping tool, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. when the first blade has become blunt. All that is required is for a new blade to be inserted and the outer sleeve replaced on the inner wrapping bit. The outer sleeve serves to hold the blade in position in the slot during operation. It may not be necessary to have a groove such as 7 which accommodates the insulated wire. For example the groove could be replaced by a flat on the inner part. WHAT WE CLAIM IS:

1. A wire stripping and wrapping tool comprising a first part having a bight for locating an insulated wire laid in it, a second part constrained to slide adjacent the first part backwards and forwards past the bight, there being an elongate space extending between the parts from adjacent the bight in the direction of relative movement for accommodating the insulation, there being a blade mounted on the second part transversely of the space and defining with the first part an aperture smaller than the insulated wire, whereby with a wire in the bight relative movement between the parts will cause the wire insulation to be caught on the edge of the bight and cut on one side by the blade as the blade advances past the bight, continued relative movement causing the insulation to tear at the other side, the tool having an aperture at its end which fits over a terminal to be wrapped, whereupon the parts can be rotated to cause the wire to be wrapped around the terminal and simultaneously stripped of its insulation.

2. A tool as claimed in claim 1, wherein the blade is removably mounted in a slot so as to be replaceable.

3. A tool as claimed in claim 2, comprising at least two such slots, axially spaced from one another, whereby the length of insulation to be stripped can be altered, as desired.

4. A tool as claimed in any preceding claim, wherein the first part comprises a sleeve having a transverse opening and the bight at the bottom of the opening, the second part comprising a rod which can slide axially in the sleeve, the rod having a flat or groove in it to form the space.

5. A tool as claimed in any preceding claim wherein the blade has a V-shaped cutting edge.

6. A tool as claimed in any preceding claim, wherein the second part has a nose just forward of the blade and which serves to bend a wire lying in the bight before the blade cuts the insulation.

7. A wire stripping and wrapping tool, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.