Cutting, Stripping, And Wrapping Bit For Insulated Conductor Wire

Abstract

A bit and sleeve assembly for cutting, stripping and wrapping an insulated conductor comprising a rotary wrapping bit mounted within a fixed tubular sleeve. The bit includes a longitudinal conductor receiving groove having disposed therein a transverse cutting edge or blade insert cooperable with the sleeve to cut the conductor insulation upon commencement of the wrapping operation. The sleeve includes a radially extended wall portion forming an opening to the bit end face which is alignable with the conductor receiving groove to facilitate loading an insulated conductor into the groove. An opening in the sleeve alignable with the conductor receiving groove defines a cutting edge cooperable with the bit to cut a predetermined length of wire to be wrapped.

Description

BACKGROUND OF THE INVENTION

In the art of making solderless electrical connections by wrapping a flexible conductor wire about a terminal in a series of helical convolutions, devices are known which are operable to cut a predetermined wire length to be wrapped, strip the insulation, and wrap the bare conductor on the terminal. Such devices are commonly known as combination wrapping bits or tools and they are particularly advantageous for use in making wrapped connections in field installation and repair of communications equipment because they eliminate the need for separate tools to perform each operation. Combination cutting, stripping and wrapping bits are disclosed in U.S. Pats. Nos. 2,682,063 to H.A. Miloche; 2,807,810 to E. Belek et al; 3,393,715 to F.G. Finn; and 3,544,243 to R.A. DeRose et al.

A deficiency realized with certain prior art stripping and wrapping tools includes the provision of a sleeve which only partially surrounds a rotatable bit device. These bit and sleeve combinations are designed to provide for loading the conductor wire into the bit device by substantially transverse movement of the wire with respect to the longitudinal axis of the bit to lay the wire into the receiving portions of the bit and sleeve. Partial sleeves whether fixed or rotatable do not provide for suitable containment or support of the wire prior to and during the stripping and wrapping operations nor do they suitably retain the stripped piece of insulation to prevent entanglement of same in the bit as it rotates. It has been determined that containment of the conductor portion which is to be stripped and wrapped to prevent any kinking or bending is important to providing wrapped connections which are consistently tight on the terminal within close tolerances. Also, it has been determined that stripping and wrapping devices having rotating sleeves and devices having bits without sleeves have proven to be troublesome in use with hand-held conductor wrapping tools because they usually catch and entangle the length of wire leading away from the end portion being wrapped.

Prior art stripping and wrapping bits are also characterized for the most part by integrally formed cutting edges for cutting through the insulation to be stripped. Integral cutting notches or edges are disadvantageous in that damage to or dulling of the cutting edge requires costly repair work on the bit or replacement of the complete bit.

Another longstanding problem in the art of combination conductor wrapping bits concerns the provision of a bit and sleeve construction which does not require the sleeve to be axially movable with respect to the bit but which still provides for rapid and easy insertion of the conductor end to be stripped and wrapped into the conductor receiving groove in the bit without bending or kinking the conductor itself. Particular care must be taken not to kink or bend the conductor before wrapping because such action will increase the extraction force required to withdraw the wire from the conductor receiving groove and will, accordingly, result in overstressed wrapped connections.

SUMMARY OF THE INVENTION

The present invention provides improved means for cutting, stripping and wrapping insulated conductor wire whereby a single rotary tool of simple construction and requiring a minimum of operator skill may be used to prepare and wrap insulated conductors.

The present invention also provides a combination bit for cutting a predetermined length of conductor to be wrapped, stripping a predetermined length of insulation from the conductor end, and wrapping the stripped conductor end portion about a terminal in one continuous operation. With the stripping and wrapping bit of the present invention superior containment of the conductor portion to be stripped and wrapped is provided to prevent bending and entanglement of the conductor or insulation. Furthermore, with the present invention entanglement or damage to the conductor portion leading away from the stripped end portion is also prevented.

The present invention further provides a combination stripping and wrapping bit for insulated conductor wire in which the stripped insulation portion is retained in the conductor-receiving groove during the wrapping operation and is automatically ejected by inserting the next piece of insulated conductor preparatory to a stripping and wrapping operation. Moreover, the present invention provides for a stripping and wrapping bit for insulated conductor wire which is easily loaded with a conductor end portion without bending or jamming the conductor itself.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side view of a portable rotary tool including the combination conductor wrapping bit and sleeve assembly of the present invention;

FIG. 2 is a transverse view of the end face of the conductor wrapping bit and sleeve assembly of the present invention;

FIG. 3 is a longitudinal section view taken along the line 3--3 of FIG. 2;

FIG. 4 is a transverse section view taken along the line 4--4 of FIG. 3;

FIG. 5 is a transverse section view taken along the line 5--5 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing a rotary power tool is illustrated in FIG. 1 and generally designated by the numeral 10. The tool 10 illustrated is of the self-contained electric type having a battery contained within the handle portion 12 for driving a suitable motor, not shown, disposed within the tool housing. The tool 10 is intended to be exemplary of a type of tool which may suitably be used with the present invention. Those skilled in the art will recognize that other types of tools including fluid operated as well as manually actuated types may also be used.

The tool 10 is adapted to support and drive an improved device, generally designated by the numeral 14, for cutting, stripping, and wrapping an insulated conductor on a terminal. The tool 10 includes a hollow nose portion 16 in which is journaled a rotary spindle 18 suitably connected to the aforementioned motor. The nose portion 16 also includes a stationary cylindrical collet and nut assembly 20 comprising means for removably retaining an elongated tubular sleeve 22 nonrotatably with respect to the tool 10. Rotatably disposed within the tubular sleeve 22 is an elongated cylindrical member 24 comprising a bit which is cooperable with the sleeve to operate on a flexible insulated conductor wire by cutting and stripping a predetermined length of insulation from the conductor end portion and wrapping the stripped end portion on a suitable terminal. The bit 24 includes a cylindrical end portion 26 having a transverse surface 28 and a projection 30 which is in driving engagement with a complementary projection 32 on the spindle 18. As shown in FIG. 1 the transverse surface 28 is engaged with one end of the sleeve 22 within the collet 20 to prevent unintentional displacement of the bit from the sleeve.

Referring to FIGS. 2 through 5, the bit 24 includes at its opposite end a transverse end face 34. A terminal receiving bore 36 is disposed in the bit and opens to the end face 34. Disposed about the bore 36 is a generally U-shaped axially sloping surface 38 which intersects the transverse end face 34 and a parallel transverse surface 40. The surface 38 is provided for camming a flexible conductor wire onto a terminal post in a known way and disclosed in detail in U.S. Pat. No. 3,078,052 to W.L. Olds et al. The end face configuration of the bit 24 is intended to be exemplary and it will be understood that the novel features of the improved stripping and wrapping device 14 may be used with other wrapping bit end face configurations.

The bit 24 is further characterized by an elongated conductor receiving groove 42 parallel to and radially offset from the terminal receiving bore 36. The groove 42 has a generally U-shaped cross sectional configuration and opens to the periphery of the bit. The groove 42 also opens at one end to the end face 34 of the bit. The opposite end of the groove 42 is characterized by a sloping surface portion 44 which is adjacent an opening 46 in the wall of the tubular sleeve 22. The bit 24 also includes a substantially transverse slot 48 spaced a predetermined distance from the end face 34 in which is removably disposed a thin metal blade 50 having a notch forming an insulation cutting edge 52. The spacing of the blade 50 from the end face 34 provides for at least a partial convolution of insulated conductor to be wrapped on a terminal. The slot 48 is formed at a slight angle, about five degrees, with respect to a plane perpendicular to the longitudinal axis of the bit 24 to facilitate the cutting action of the edge 52. The cutting blade 50 is retained in the slot 48 by the surrounding sleeve 22. The cutting edge 52 may also be formed integral with the bit 24, however, the removable blade 50 provides for rapid and economical replacement of the cutting edge without replacing the entire bit. As may be appreciated from viewing the drawing, the conductor receiving groove 42 is dimensioned to accommodate an insulated conductor and the notch forming the cutting edge 52 is dimensioned to be slightly greater in width than the diameter of the conductor wire. Accordingly, when an insulated conductor is forced radially, with respect to the bit axis, into the groove 42 the edge 52 makes at least a partial circumferential cut through the conductor insulation.

The tubular sleeve 22 substantially surrounds the bit 24 in close fitting relationship and encloses a major portion of the groove 42. The sleeve 22 includes a pair of notches 54 and 55 opening to the end of the sleeve adjacent the end face 34 and disposed diametrically opposite each other. The sleeve 22 further includes a radially outwardly relieved tubular wall portion 56 which also extends axially away from the end of the sleeve and beyond the insulation cutting blade 50. The wall portion 56 forms a guide surface 58 having a portion 61 which slopes radially inwardly with respect to the longitudinal axis of the bit. The guide surface 58 provides means for inserting an insulated conductor longitudinally from the open end of the sleeve past the cutting blade 50, into the groove 42, and toward the opening 46 in the sleeve. As shown in FIGS. 2 and 4 the blade 50 includes relieved portions 53 which provide clearance for inserting a conductor along the guide surface 58 and past the blade. The guide surface 58 may be formed by a suitable metal forming process by displacement of the tubular sleeve wall.

As shown in FIGS. 2 through 5 the guide surface 58 and opening 46 in the sleeve are disposed in alignment with the conductor receiving groove 42 prior to insertion of a conductor to be stripped and wrapped. A suitable indexing mechanism 59 in the tool 10 provides for indexing the rotatable bit 24 to the position shown at the termination of the previous operating cycle of the tool. An insulated conductor C, shown by dashed lines in FIGS. 2 and 3, may be manually inserted from the open end of the sleeve 22 through the opening formed by the extended wall portion 56 and guided into the groove 42 by the guide surface 58. The conductor C is inserted into the groove until a small portion 63 extends out through the opening 46 in the sleeve to assure that a predetermined length of stripped conductor portion will be provided for wrapping. When the conductor C is inserted in the groove the tool operator trains the conductor through the notch 54, FIG. 2, and holds the portion 62 leading away from the inserted end along the exterior of the sleeve. The direction of bit rotation is indicated by the arrow in FIG. 2. If it was desired to rotate the bit in the opposite direction, the notch 55 would be used.

After insertion of the conductor in the bit 24, the tool is placed over a terminal, not shown, in a known way and the tool motor is energized to rotate the bit. Almost immediately on commencing rotation the conductor end portion 63 is severed by the cutting edge 60 formed by the longitudinal side of opening 46 in the sleeve as the groove 42 moves past the opening. The conductor C, held stationary with respect to the sleeve 22 at the notch 54, is pulled down into the notch in the insulation cutting blade 50 due to the rotational movement of the bit whereby a partial cut through the insulation is made without nicking the conductor wire. The forcing of the conductor C into the notch forming the cutting edge 52 is assisted by engagement of the conductor by the inner wall surface of the sleeve as the groove 42 rotates away from the opening formed by the wall portion 56. Many types of insulation require only a partial transverse cut to provide for total severance by tearing the remaining uncut portion without extruding the insulation remaining on the conductor. Accordingly, with the bit and sleeve assembly disclosed, continued rotation of the bit 24 will cause complete severance of the insulation at the blade 50 as the conductor is withdrawn from the groove 42 and wrapped around a terminal.

As the conductor C is withdrawn from the groove 42 by continued rotation of the bit the severed insulation will be retained in the groove by the completely circumferential tubular sleeve and the blade 50 and will be prevented from becoming entangled in the bit or sleeve. Moreover, due to the fact that the sleeve 22 is stationary there is no danger of entangling the conductor portion 62 leading away from the bit end face 34. The severed insulation portion will remain in the groove 42 and will be ejected through the opening 46 by insertion of an insulated conductor in preparation for a succeeding operation of the tool 10.

As may be appreciated from the foregoing description, the improved bit and sleeve combination disclosed herein provides for a relatively simple operation to load an insulated conductor into the groove 42 without bending or kinking the conductor wire thanks to the guide surface 58 formed by the extended wall portion 56. Moreover, the superior containment characteristics of the bit and sleeve prevent accidental displacement and entanglement of the conductor or the insulation portion being stripped during the stripping and wrapping process. It is particularly significant that the stripped insulation portion is retained in the groove 42 until completion of the operating cycle of the tool whereby the insulation portion is not free to fall into the work area or become entangled in the conductor during routing of same to the next terminal.

Claims

We claim:

1. In a device for stripping insulation from a flexible conductor wire and wrapping said wire on a terminal in a series of helical convolutions:

a rotatable wrapping bit comprising;

a bit end face;

a terminal receiving bore opening to said end face;

a longitudinal wire receiving groove disposed on the periphery of said bit and radially offset from said terminal receiving bore and opening at one end to said end face; and

a cutting edge disposed in said groove for cutting the insulation of a wire disposed in said groove; and,

an elongated tubular sleeve fixed substantially axially with respect to said bit and disposed around said bit to substantially enclose a major portion of said groove, one end of said sleeve being disposed adjacent said end fae, said sleeve including means comprising a radially outwardly relieved tubular wall portion extending axially from said one end of said sleeve toward said cutting edge and forming an opening to provide for inserting said wire longitudinally with respect to said bit past said cutting edge and into said groove.

2. In a device for stripping insulation from a portion of a flexible conductor wire and wrapping said portion on a terminal in a series of helical convolutions:

a rotatable wrapping bit comprising;

a bit end face;

a terminal receiving bore opening to said end face;

a conductor receiving groove disposed on the periphery of sad bit parallel to and radially offset from said terminal receiving bore and opening at one end to said end face; and

a cutting edge disposed in said groove for cutting the insulation of an insulated conductor wire disposed in said groove; said cutting edge being formed on a cutting blade removably retained in a transverse slot formed in said bit and intersecting said groove; and,

an elongated tubular sleeve fixed axially with respect to said bit and disposed around said bit to substantially enclose a major portion of said groove.

3. The invention set forth in claim 2 wherein: said cutting blade is retained in said groove by said sleeve.

4. The invention set forth in claim 1 wherein:

said radially outwardly relieved wall portion forms a guide surface extending from said one end of said sleeve to said cutting edge.

5. The invention set forth in claim 4 wherein:

said sleeve includes an opening disposed adjacent the end of said groove opposite said one end and forming a cutting edge for severing an end portion of a wire disposed in said groove in response to rotation of said bit.

6. The invention set forth in claim 5 wherein: said guide surface is axially aligned with said opening forming a cutting edge for severing an end portion of a wire.