TOOL DRESSING APPARATUS AND METHOD

Abstract

A tool is provided for dressing the worn or damaged tip of a welding electrode tip. Electrode tips are typically nominally frusto-conical, and have a pre-determined design taper. The dressing tool has a body. The body has a bore formed to receive the frusto-conical electrode tip. When so received, the body is rotated about the tip. The bore has a dressing member for engagement with the frusto-conical member, the two parts having corresponding design tapers. The body has a torque input interface by which, in use, the tool may be turned by an input torque to cause said tool to turn about the electrode tip, and in so doing to cause said dressing member to hone the tip. The dressing member includes a region of abrasive grit. Different grades of grit may be used. The tool may have an opposed socket suitable for seating on the opposed electrode tip, thereby centering the device automatically and correctly. The tool may be in either male or female form. The handle used to turn the tool may carry information.

Description

This application claims the benefit of priority under 35 USC 119 on the basis of U.S. Provisional patent application U.S. Ser. No. 61/616,066 filed Mar. 27, 2012 of the same title, the specification and drawings thereof being incorporated by reference herein in their entirety.

FIELD OF INVENTION

This Application relates to a tool dressing apparatus, or hone, and a method of operating that apparatus.

BACKGROUND OF THE INVENTION

In the manufacture of mass-produced products a production line may involve the sequential assembly of parts using a large number of welding stations. At each welding station there may be a welding tool having first and second electrodes. Each welding operation involves establishing the two parts to be welded in a position between the first and second electrodes, closing the electrodes on the assembly at the location to be welded, making the weld, and then releasing the weld and moving on to the next location to be welded. Often the welding machine is a robot. Often the production line is designed for the manufacture such things as automobiles, or for white goods such as refrigerators, freezers, stoves, and so on.

The welding tools generally have two such electrodes that come together to make the weld, with the parts being squeezed under some contact pressure between them. The electrodes typically have an electrode arm that ends in the electrode. The electrode is most generally made of copper. The end of the electrode generally carries a cap, which may have a size and shape suitable for making the desired weld. The cap is also typically made of copper or a copper alloy, and may be hollow. The root, or base, of the cap may be substantially annular, and may have the form of a truncated conical section. The tip of the cap will have a size and shape suitable for the objects to be welded. The end of the welding electrode will have a truncated conical exterior wall, similar to that of the cap. In use, the conical skirt of the cap will seat on the conical exterior of the electrode in a tight interference fit. This is desirable, since the better the fit, the better the conduction of electricity from one to the other. The electrode may sometimes be hollow, and may include a coolant delivery tube or conduit mounted within a return passage (which may be co-axial), the coolant being delivered to circulate inside the welding cap, generally with the objective of cooling the cap and thereby increasing the number of welds that can be made per unit of time with the tool, or increasing the service life of the cap. It may be noted that the skirt of the cap may not always have the exactly the same taper as the conical wall of the electrode.

The welding, work-piece contacting, contact end of the cap may, at least initially, be substantially spherical, or it may have the shape of a truncated cone, or it may have some other shape. At the tip of the cap there may be a coating of some kind, be it titanium carbide or titanium boride, or some other coating, such as may tend to delay deterioration of the cap.

The caps are consumable items. Over time, the repeated welding, and closing pressure, and high temperatures applied while the tool is forming the weld nugget in the objects to be welded tends to cause the cap to deteriorate. After some period of time, perhaps several hundred or possibly a thousand or more welds, the cap will no longer be fit for service. The cap will then be removed from the electrode.

The electrode may also typically have a shoulder adjacent to the frusto-conical portion. When the cap is due for replacement, a tool, such as a fork with tapered tines, or a bifurcated chisel, is thrust between the shoulder and the bottom face of the skirt of the welding cap. The fork may then be used to pry the old cap off the frusto-conical end of the electrode. The process of removal may not necessarily be overly fastidious. In the event that the fork tool has been lost or mis-laid, or in the event that the tool operator is not inclined to take the time to use the correct tool, the welding cap may sometimes be removed in a process lacking both subtlety and finesse, by means of a clamping or other tool having jaws that can grip the used cap. Tools sold under the commercial trade name “Vise-Grip” (t.m.) are sometimes used for this ungentle purpose. The removal step may then not be the predominantly axial prying associated with a fork, but rather a twisting and yanking motion to loosen the cap by rotation about the end of the electrode, the loosening being accompanied by a component of axial dis-engagement. As may perhaps be imagined, incautious removal in this manner may not necessarily tend to enhance electrode life.

Once the old cap has been removed, a new cap may be installed. One method of installing a new cap is to place the cap on the electrode, and gently to tap it into place using a leather-covered mallet or soft rubber hammer. The tool is then closed, with no electric power, and the closing pressure of the two electrode heads mating will cause the cap to seat fully. Alternatively, some operators may place the welding cap on the associated electrode and drive it into place with a hammer, such as may be convenient.

In a high volume production line it may be necessary to change welding caps several times per day. In aluminum welding, cap changes may be quite frequent. It is typically not convenient to shut a production line down to changing welding caps. Usually, one machine can be temporarily shut down to allow electrode cap replacement without shutting down the entire line. The temporary disruption may be of the order of 30 seconds to a minute, and possibly up to 90 seconds. It is unlikely to exceed 2 minutes. A single machine operator may thus be responsible for removing and replacing welding caps for many machines in a production line, either sequentially as he moves along the line, or on an as-needed basis.

Over time the installation and removal of the welding caps on the electrodes may tend to result in damage to the tapered end portions of the electrodes, making it more difficult to obtain proper seating of the new welding caps. Welding caps, which are intended to be consumable, tend to be relatively inexpensive (perhaps $2 each, or less) and easily replaced. By contrast, welding electrodes, or electrode arms, which may be several feet long, which may include internal cooling passageways and delivery systems, and which may be formed in a particular shape according to the needs of the manufacturing process are replaceable, but relatively much less frequently, and a relatively far higher cost.

Furthermore, the time required to replace a welding arm may be very much greater than the length of time required to replace a welding cap. The cost of shutting down a production line even for a brief period may be very much higher than the cost of replacing an arm. Quite often it may be desirable to avoid changing the electrode arms during production, and to wait instead until the line is shut down for planned maintenance, be it on the night shift, a weekend shift, or as may be.

One cause of a need for removal and replacement of the electrode arm is that the frusto-conical end of the electrode is no longer serviceable to receive new welding caps. When the end of the welding electrode is damaged, it may be difficult properly and quickly to change welding caps. It may be desirable to have a tool that may tend to permit the frusto-conical end of the welding arm to be dressed between tool replacement intervals more closely to resemble its original un-damaged form, and to do so relatively quickly, without necessarily requiring the entire production line to be stopped, such as may permit the electrode arm to continue to function until a more convenient replacement time, be it the end of the a shift or until the next planned maintenance interval may permit more cycles of production to occur between electrode arm replacement.

SUMMARY OF INVENTION

The following summary is provided to introduce the reader to the more detailed discussion to follow. The summary is not intended to limit or define the claims.

According to an aspect of the invention, there is a tool for dressing a nominally frusto-conical member, the frusto-conical member having a pre-determined design taper.

The dressing tool has a body. The body has a bore. The bore is formed to receive the frusto-conical member therewithin and to permit rotation of the body about the frusto-conical member when so mounted. The bore has a dressing member for engagement with the frusto-conical member, the dressing member having a taper angle corresponding to the design taper of the frusto-conical member. The body has a torque input interface by which, in use, the tool may receive an input torque to cause the tool to turn about the frusto-conical member, and in so doing to cause the dressing member to hone the frusto-conical member. The dressing member includes a region of abrasive grit.

In a feature of that aspect of the invention the apparatus has an handle. The handle has a seat for receiving the body. The handle has a torque transmission member that, when assembled, engages said torque input interface of said body of said tool and permits a person grasping said handle to cause said body to turn. In another feature, the handle has the form of a spider. The spider has an interior portion defining the seat. There is at least one web portion extending away from the seat in a direction having a component tending radially away from the seat. The spider has an exterior portion most radially distant from the seat and extending predominantly peripherally relative thereto. The exterior portion defines a grip by which to grasp the spider and turn the tool about the frusto-conical member. In another feature, the abrasive grit is one of: (a) a sintered powder comprising the abrasive grit; and (b) a coating of the abrasive grit deposited on an interior wall of the bore. In a still further feature, the tool has an exterior wall, and the exterior wall includes a flat portion. In yet another feature, the tool has an exterior wall, and the exterior wall has an at least partially crenelated portion. In a further feature, the tool is encapsulated in a moulded carrier.

In another feature of the invention the seat is a first seat, and the tool also has a second seat. The second seat is formed to engage another member located co-axially relative to the frusto-conical member to be honed. The first and second seats are on opposite sides of the tool. In still another feature, the second seat has a bearing mounted therein to facilitate rotation of the tool relative to the co-axial other member. In a further feature, the tool includes an handle having a seat for receiving the body. The handle has a torque transmission member that, when assembled, engages the torque input interface of the body of the tool and permits a person grasping the handle to cause the body to turn.

In another aspect of the invention, there is a method of dressing a welding electrode member using a tool for dressing a nominally frusto-conical member of the welding electrode, the frusto-conical member having a pre-determined design taper, the dressing tool having a body having a bore formed to receive the frusto-conical member therewithin and to permit rotation of said body about the frusto-conical member when so mounted, the bore having a region of abrasive grit, the bore having a taper angle corresponding to the design taper of said frusto-conical member, the welding electrode member having a tapered tip defining the frusto-conical member. The method includes establishing the electrode in an open condition relative to an opposite, mating, electrode; removing an existing welding cap from the electrode tip to expose the frusto-conical member; seating the tool on the exposed frusto-conical member; and rotating the tool about the frusto-conical member, thereby honing the frusto-conical member.

In a further aspect of the invention there is a tool for dressing a nominally frusto-conical member, the frusto-conical member having a pre-determined design taper. The said dressing tool has a body that may be suited for either a male or a female tool to be honed. That body has one of (a) where the frusto-conical member is a male part, an accommodation, that accommodation being formed to receive the male frusto-conical member therewithin and to permit rotation of the body about the frusto-conical member when so received, the accommodation having a dressing member for engagement with the frusto-conical member, the dressing member having a taper angle corresponding to the design taper of said frusto-conical member; and (b) where the frusto-conical member is a female part, a protrusion, that protrusion being formed to engage the female frusto-conical member therewithin and to permit rotation of the protrusion within the female frusto-conical member when so received, that protrusion having a dressing member for engagement with the frusto-conical member, the dressing member having a taper angle corresponding to the design taper of the female frusto-conical member. Whether male or female, the body has a torque input interface by which, in use, the tool may receive an input torque to cause the tool to turn relative to the frusto-conical member, and in so doing to cause the dressing member to hone the frusto-conical member. The dressing member includes a region of abrasive grit.

In a further feature of that aspect of the invention, after the step of seating and before the step of rotating, the method further includes the step of closing the electrode relative to the opposite, mating, electrode. In a still further feature, the tool has a second seat, and the step of closing includes seating the opposite electrode in the second seat whereby the tool is stabilised relative to the axis of the frusto-conical electrode member. In a further feature, the method includes removing the tool, reversing the tool and honing a corresponding frusto-conical member of the opposite electrode as well.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

The foregoing aspects and features of the invention may be explained and understood with the aid of the accompanying illustrations, in which:

FIG. 1a is a general arrangement view on a cross-section of a welding apparatus with a dressing tool in position to hone a worn electrode;

FIG. 1b is a perspective view of a welding gun with its welding caps removed, ready for dressing of the electrodes;

FIG. 1c is a perspective view of the dressing tool of Figure la seated on the lower electrode;

FIG. 1d is a perspective view showing the movable electrode entered into a guide of the dressing tool, ready for honing to commence;

FIG. 2a shows an insert of the honing tool of Figure la in isometric view;

FIG. 2b shows the insert of FIG. 2a in plan view;

FIG. 2c shows the insert of FIG. 2a in side view;

FIG. 2d shows the insert of FIG. 2a on section 2d—2d of FIG. 2a;

FIG. 3a shows a carrier for the insert of FIG. 2a in perspective view, showing the seat for the insert;

FIG. 3b shows a back side perspective view of the carrier of FIG. 3a;

FIG. 3c is a plan view of the carrier of FIG. 3a;

FIG. 3d is a side view of the carrier of FIG. 3a;

FIG. 3e is a section of the carrier of FIG. 3a on section 3e—3e of FIG. 3c;

FIG. 4a is a plan view of an alternate insert to the insert of FIG. 2a;

FIG. 4b is a side view of the insert of FIG. 4a;

FIG. 4c is a section of the insert of FIG. 4a;

FIG. 5a is an end view of an alternate embodiment of dressing tool insert to that of FIG. 2a; and

FIG. 5b is a side view of the dressing tool insert of FIG. 5a.

DETAILED DESCRIPTION

The description that follows, and the embodiments described therein, are provided by way of illustration of an example, or examples, of particular embodiments of the principles of aspects and features of the invention. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the invention. In the description, like parts are marked throughout the specification and the drawings with the same respective reference numerals. The drawings may be taken as being to scale, or generally proportionate, unless indicated otherwise.

The scope of the invention herein is defined by the claims. Though the claims are supported by the description, they are not limited to any particular example or embodiment, and any claim may encompass processes or apparatuses other than the specific examples described below. Other than as indicated in the claims themselves, the claims are not limited to apparatuses or processes having all of the features of any one apparatus or process described below, or to features common to multiple or all of the apparatus described below. It is possible that an apparatus or process described below is not an embodiment of any claimed inventions.

The terminology used in this specification is thought to be consistent with the customary and ordinary meanings of those terms as they would be understood by a person of ordinary skill in the art in North America. Following from the decision of the Court of Appeal for the Federal Circuit in Phillips v. AWH Corp., the Applicant expressly excludes all interpretations that are inconsistent with this specification, and, in particular, expressly excludes any interpretation of the claims or the language used in this specification such as may be made in the USPTO, or in any other Patent Office, other than those interpretations for which express support can be demonstrated in this specification or in objective evidence of record in accordance with In re Lee, (for example, earlier publications by persons not employed by the USPTO or any other Patent Office), demonstrating how the terms are used and understood by persons of ordinary skill in the art, or by way of expert evidence of a person or persons of experience in the art.

Reference is made herein to welding electrode tips and caps. In respect of each tip or cap, it may be helpful to define a polar-cylindrical co-ordinate system, in which the axial, or z-direction defines the axis about which the cap or electrode tip is formed, or has a surface, on a body of revolution, the term radial refers to a distance away from the z-axis, and circumferential refers to an angular direction about the z-axis.

Referring to the general arrangement of FIGS. 1a and 1b, there is a welding apparatus, indicated generally as 20. It includes a first welding arm, indicated generally as 22, and a second welding arm, indicated generally as 24. Each arm includes a respective welding electrode 26, 28, each of which, in operation, has a welding cap, 30. In use, arms 22 and 24 are brought together by a closing motion in the axial direction, or z-direction, such that their respective caps close on either side of, and sandwich together under a closing force, the two work-piece members that are to be welded. It may be that each electrode has a cooling passage formed therein for a coolant delivery tube or conduit 32, and a return passage 34.

At the end of each arm is an electrode end, or tip, or termination 40. Termination 40 may have the form of a truncated cone, i.e., a frusto-conical section, having an upper end or margin shown as a flat cut top as at 42, and a descending, outwardly tapered peripherally extending conical skirt or wall as at 44. The conical wall has a lower margin that terminates at a radially outwardly extending shoulder 46 that extends radially proud of the surface of revolution (i.e., the conical surface) in which the outer face of wall 44 lies. If electrode termination 40 is hollow, so as to admit circulation of cooling fluid, wall 44 may also have an internal face 48. The taper of wall 44 is shown by angle alpha. This taper, and the geometry of the electrode end more generally, may be subject to an industry standard, whether in Japan or the United States or elsewhere, such that welding caps of different welding cap suppliers are supposed to fit and be interchangeable on the welding end geometry specified by the standard.

A dressing tool, or hone, or apparatus is shown generally as 50. In the embodiment described it may include a body 52, and a carrier 54. Body 52 may have the general shape of an annular boss having an outer wall 56 and an inner wall or inner bore 58, and end walls or end faces 57 and 59. Top and bottom end faces 57 and 59 may lie in radially extending planes perpendicular to the axial direction. To the extent that body 52 has greater depth than the height of wall 44, indicated as H₄₄, inner bore 58 may be a blind bore. However, inner bore 58 may conveniently be a through-bore 60, having a first open end 62 defined by an opening in top end face 57 and a second open end 64 at the opposite end of through-bore 60 defined by an opening in bottom end face 59. The ends of through-bore 60 may be chamfered, or radiused, or otherwise relieved as indicated at 61. Inner bore 58 has a wall 66 that is tapered at an angle beta. Beta may generally be taken as being the same angle as angle alpha. It may be appreciated that only one end of the bore need be tapered, namely the end that is to engage the object to be honed.

Inner bore 58 includes a dressing member or feature or element 70, such that when apparatus 50 is engaged with a worn or damaged electrode, element 70 will dress the surface of the electrode to return it to its proper shape for receiving a new welding cap. Element 70 may have the form of an abrasive grit. The abrasive grit may be a diamond-based abrasive grit. The abrasive grit may be quite fine. In some embodiments it may be 400 grit or finer. (Or, alternatively, there may be several versions of apparatus 50, with progressively finer grits for coarse, medium, and fine dressing.) It may be that a modestly fine grit may leave a surface that is “roughened” in a manner suitable for receiving a new welding cap and, as the cap seats more tightly, the more-or-less random asperities of this roughness may deform to give good contact engagement. To the extent that a diamond grit or coating or plating may be applied to surface 70, that coating may be applied not only to the tapered or main portion of wall 66 but also to the radiused portion as at 61.

The grit may be incorporated by any suitable means. For example, the grit may be incorporated in a sintered powder in the form of a sintered powder insert. Alternatively, the grit may be deposited on the inner surface of the bore by such means as chemical vapour deposition, or such other plating process as may be appropriate. The thickness of the abrasive grit coating or powder need not be great. It may be less than 0.020″. In some embodiments it may be less than 0.010″. In one embodiment it may be about 0.006″.

Although inner bore 58 is shown as being formed on a continuous circumferential circular (at any given z) axially tapered wall, this need not be so. Bore 58 may have one or more segments defining a non-continuous footprint when engaged with the electrode tip, with spacing between the segments, as may be. A three-, or four-leafed pattern might be used, for example.

Outer wall 56 may have, or include, an external torque transmission interface 72, which may have many forms. In one embodiment, outer wall 56 has a first portion 74 and a second portion 76. First portion 74 may be formed on a substantially circular cylindrical arc. Second portion 76 may be formed as one or more flats 78. It may be that the entire peripheral of outer wall 56 may be formed of flats, such that the outside of body 52 defines a multi-sided nut that can be grasped by a suitable corresponding wrench, or apparatus having a wrench-like function of transmitting torque to body 50, and then, ultimately, to the electrode tip to be dressed. Where it is envisioned that more than one grade of grit may be used for coarse and fine honing, or possibly including intermediate “medium” grit tools, each such tool may be given an identifier in its respective body 52, whether by means of a number of dots or dimples or a letter or numeral embossed or engraved in an end face.

It is possible that apparatus 50 could include body 52, and no more. However, not all persons may be possessed of such finger and hand strength as may be appropriate merely to grasp body 50 and turn it to provide the desired honing. For whatever reason it may be convenient for apparatus 50 to include a carrier 54 into which body 52 may seat. Carrier 54 may play the double role of being a carrier for body 52, and also of providing a torque transmission element that may itself be grasped any turned to drive body 52.

To that end, carrier 54 may include a radially inner portion, or spindle, or hub, defining a bore, or pocket, or accommodation, or seat, 80. Seat 80 may be formed as the negative image of outer wall 56, and, in some instances, the fit between seat 80 and body 52 may be established by moulding seat 80 about body 52. This may be expressed, equivalently, by indicating that seat 80 may be an insert placed in the mould of carrier 54, and the matrix of carrier 54 may be cast in the mould about body 52, thus capturing it. Seat 80 includes a torque transmitting element 81, whether being the negative image of the outside face or shape or form of body 52, or merely including one or more features that define a geometric arrangement oriented to engage body 52 in a torque transmitting relationship. It is not, however, necessary that seat 80 fully surround body 52, or that the seat be a zero-tolerance (i.e., full, permanent contact) seat. Rather, in some embodiments a seat may be defined by a segment, or number of segments, which may be segregated from each other, sufficient to transmit torque to body 52. That is, in some instances, such as where different grades of grit may be used progressively, it may be desirable to be able to substitute the various grades by removing and replacing one body 52 with another. In such a case, the socket-and-wrench relationship may include a detent, which may be spring-loaded, by which body 52 snaps into place, and removal being achieved by pushing on the upper end face 57.

Alternatively, for each different grade of grit, body 52 may be supplied with a permanent carrier 54, from which it is intended to be inseparable other than by, for example, destruction of the carrier. In that case, carrier 54 itself may bear an identifier by which the grade of grit may readily be determined, be it by a physical feature such as an embossment or engraved feature, or series thereof, that can be determined by feel; or by making the carrier of a different colour of plastic (e.g., red, green blue, etc.), or both, as may be. Indeed, carrier 54 may be labeled in writing “coarse”, “medium”, “fine”, and so on. Although fabrication of carrier 54 by plastic moulding is suggested herein by the inventor, there is nothing preventing other embodiments from being made by casting metal, be it aluminum, steel, bronze, brass or some other alloy, or by being made of wood, of it being machined from solid, of otherwise fabricated. On the whole, however, plastic moulding may be expedient.

Carrier 54 may include not only the interior portion or hub, such as seat 80, but also an exterior portion 82, and a radially intermediate portion 84 extending between seat 80 and exterior portion 82. Exterior portion 82 may define a handle, or hand grip, with one or more features, such as knobs, or scallops, or finger grips, or a roughened, or knurled, surface such as may enhance grip. Exterior portion 82 may extend fully circumferentially, as a ring or rim, or fully continuous peripheral wall. However, this need not be so. Exterior portion 82 could be formed of a single arm, or a plurality of arms, or sectors.

Intermediate portion 84 defines a torque or moment couple transmission medium extending between seat 80 and exterior portion 82. Intermediate portion 84 may have the form of a substantially continuous radially extending web 86, the web functioning in shear to transmit torque. Alternatively, web 86 may have openings formed therethrough, as at 88, and those openings may be flanged or have radially extending ribs as at 90, 91 such that the elements of web 86 lying between the openings defined predominantly radially extending arms as at 92. Arms 92 may extend directly radially, as illustrated, or may extend in a manner that has a radial component and a circumferential component, and which may possibly have an axial component. It may be that arms 92 have a curved shape when seen in plan view, for example. Many alternatives are possible, both in shape and number. While arms 92 and openings 88 may be arranged symmetrically, or in a regularly repeated array about the inner portion, seat 80, that need not be so.

Carrier 54 may also have, on its opposite side, or face, a central portion having a socket or accommodation or bore 100 having a shape suitable for receiving, and defining a seat for, the other electrode tip when one electrode tip is being dressed. That is, it may be desirable to align carrier 54 prior to commencing dressing. One way to obtain the correct orientation of the honing tool is to close the respective electrodes, at least partially, to the point where body 52 seats on the electrode tip to be honed, and the opposite electrode seats in bore 100, thus centering apparatus 50, and permitting it to be turned, or spun, about the axis of the electrodes, without the operator having to attempt to ensure correct axial orientation manually.

Inasmuch as it is foreseen that carrier 54 may be made of an high density, relatively slippery UHMW plastic, such as a nylon, rotation about the passive electrode (i.e., the electrode that is not being honed at the moment) is not expected unduly to be impeded by such engagement. However, it is also foreseen that in some embodiments it may be desirable to form bore 100 to carry a bearing, that bearing being of appropriate inner diameter, and possibly having an insert of appropriate taper, to seat on the passive electrode tip.

The radially extending member or component, which transfers torque in shear from the outer region of the handle to the inner region of the handle may present one or more generally flat surfaces. It is foreseen that such surfaces may be imprinted or otherwise formed to carry information, be it pertaining to the tool or to such person or entity as may supply the tool, the electrodes, the tips, or an materials required in the procurement or maintenance of the electrodes, and so on.

In the further embodiment of FIGS. 4a, 4b and 4c, there is a body 102, otherwise similar to body 52, that is substantially annular, and rather than having a single flat has an exterior array of radially variant features or protrusions or dimples, etc., indicated as 104 such as may be cast into a plastic handle, such as carrier 54, and provide a suitable torque transmission interface.

In the further alternative embodiment of FIGS. 5a and 5b, there is a honing tool insert indicated generally as 110. Body 152 may be used with any of the handles shown or described hereinabove, be it 54 or some other, as may be suitable. Whereas body 52 is a female body, i.e., it has a cavity into which the male electrode tip fits, body 112 is a male body suitable for use with a female welding tip or socket. That is, while some, or most, welding caps may seat on a male welding tip, there are welding tips that have a hollow, or female, form into which a male welding cap shank seats. This hollow form may include a coolant delivery supply pipe or conduit, or tube, such as may tend to be mounted co-axially within the welding tip. As can be seen, body 112 has a first, central, or middle, portion 114 which may have the form of body 52 and may include a torque transfer interface feature, or features, 116 such as described above, which, may be a flat, or set of flats, such as may be symbolized by item 118. As above, whatever form the torque transfer interface may take (and it may have the form of any of the other embodiments shown or described herein) it serves the purpose of providing a means by which to receive torque from the handle. Body 112 may also include end faces or shoulders, identified as 120.

Body 112 includes second component or portion, namely a first end portion 122. In contrast to the female socket of body 52, first end portion 122 is, or defines, a male end portion, which is to say that it includes a stub, or nipple, or mandrel, or protrusion 124, however it may be called, that stands lengthwise proud of, and away from, the respective shoulder 120. Protrusion 124 includes or presents a honing surface or land, or array 126 which, in this case, may have a frusto-conical form i.e., (of a truncated cone), that form having a taper from a relatively wider base adjacent shoulder 120 to a relatively narrow end 128 distant therefrom. The angle of taper may correspond to the angle of taper of a welding cap according to a welding cap standard, for example. As with the inside face of body 52, the outside face of body 112 may have an abrasive grit formed or embedded therein, in the same manner as described above. That grit may be coarse, medium or fine, as may be, and it may include, or be, a diamond grit, and the handle may be coloured or otherwise marked or identified according to the coarseness or fineness of the grit.

In the male form of hone, the protruding portion, i.e., protrusion 124, has a central cavity, or relief or accommodation, or bore, indicated as 130. Bore 130 may be of a suitable outer diameter and of a suitable length to provide clearance for the tip of the coolant delivery pipe of the welding arm. Bore 130 may be blind, or may be a through-bore extending the full way through body 112.

Body 112 may also include a second protrusion, 132, which may be the same as, or similar in structure to, first protrusion 124. The function of second protrusion 132 is the same as the function of the opposite seat of body 52, namely to provide a pick-up datum, or reference, or centering point at which to locate the opposite welding arm tip, such that, when so engaged, the tool is centered and axially aligned with the mating opposite tool, such that the hone is oriented correctly. Once oriented correctly in this way, the hone can be turned and the surface dressed as described above. In one embodiment, the tapered surface 134 of second protrusion 132 is smooth, and may be treated with a low friction surface coating, such as an UHMW polymer or a nylon, to facilitate easy rotation, i.e., as a passive guide. In another embodiment tapered surface 134 is treated with an abrasive grit in the same manner as land 126, such that when the welding apparatus is moved to its closed position, turning of the tool hones both surfaces at the same time.

In use, when the electrode tips are closed sufficiently to engage the honing tool, as described above, the operator may then turn the honing tool several times to clean up the end of the electrode tip. When one tip has been dressed, the electrodes may be spread apart again, the device reversed, the electrodes closed again and the procedure repeated on the other tip. Once the tips have been honed, new welding caps may be installed, and the machine may resume production. If more than one grade of grit is to be used, the procedure can be repeated, progressively, with finer grit tools, as may be.

Although the apparatus has been described in the context of welding electrode tips, it may also be used in other applications in which it is desired to dress, or hone, the tip of a mandrel or other similar spindle, axle, pipe nipple, or similar object. The features of the various embodiments described above may be mixed-and-matched as may be appropriate, without further redundant description of each possible combination or permutation.

What has been described above has been intended illustrative and non-limiting and it will be understood by persons skilled in the art that other variances and modifications may be made without departing from the scope of the disclosure as defined in the claims appended hereto. Various embodiments of the invention have been described in detail. Since changes in and or additions to the above-described best mode may be made without departing from the nature, spirit or scope of the invention, the invention is not to be limited to those details but only by the appended claims.

Claims

1. A tool for dressing a nominally frusto-conical member, the frusto-conical member having a pre-determined design taper, wherein:

said dressing tool has a body, said body having a bore, said bore being formed to receive said frusto-conical member therewithin and to permit rotation of said body about the frusto-conical member when so mounted;

said bore having a dressing member for engagement with the frusto-conical member, said dressing member having a taper angle corresponding to said design taper of said frusto-conical member;

said body having a torque input interface by which, in use, said tool may receive an input torque to cause said tool to turn about the frusto-conical member, and in so doing to cause said dressing member to hone the frusto-conical member; and

said dressing member includes a region of abrasive grit.

2. The tool of claim 1 and further comprising an handle having a seat for receiving said body, said handle having a torque transmission member that, when assembled, engages said torque input interface of said body of said tool and permits a person grasping said handle to cause said body to turn.

3. The tool of claim 2 wherein said handle has the form of a spider; said spider having an interior portion defining said seat; at least one web portion extending away from said seat in a direction having a component tending radially away from said seat; and said spider having an exterior portion most radially distant from said seat and extending predominantly peripherally relative thereto, said exterior portion defining a grip by which to grasp said spider and turn said tool about the frusto-conical member.

4. The tool of claim 1 wherein said abrasive grit is one of:

(a) a sintered powder comprising said abrasive grit; and

(b) a coating of said abrasive grit deposited on an interior wall of said bore.

5. The tool of claim 1 wherein said tool has an exterior wall, and said exterior wall includes a flat portion.

6. The tool of claim 1 wherein said tool has an exterior wall, and said exterior wall has an at least partially crenelated portion.

7. The tool of claim 6 wherein said tool is encapsulated in a moulded carrier.

8. The tool of claim 2 wherein said seat is a first seat, said tool has a second seat, said second seat being formed to engage another member located co-axially relative to the frusto-conical member to be honed, said first and second seats being on opposite sides of said tool.

9. The tool of claim 8 wherein said second seat has a bearing mounted therein to facilitate rotation of said tool relative to the co-axial other member.

10. The tool of claim 8 and further comprising an handle having a seat for receiving said body, said handle having a torque transmission member that, when assembled, engages said torque input interface of said body of said tool and permits a person grasping said handle to cause said body to turn.

11. The tool of claim 10 wherein said handle has the form of a spider; said spider having an interior portion defining said seat; at least one web portion extending away from said seat in a direction having a component tending radially away from said seat; and said spider having an exterior portion most radially distant from said seat and extending predominantly peripherally relative thereto, said exterior portion defining a grip by which to grasp said spider and turn said tool about the frusto-conical member.

12. A method of dressing a welding electrode member using a tool for dressing a nominally frusto-conical member of the welding electrode, the frusto-conical member having a pre-determined design taper, the dressing tool having a body having a bore formed to receive the frusto-conical member therewithin and to permit rotation of said body about the frusto-conical member when so mounted, the bore having a region of abrasive grit, the bore having a taper angle corresponding to the design taper of said frusto-conical member, the welding electrode member having a tapered tip defining the frusto-conical member, wherein the method includes:

establishing the electrode in an open condition relative to an opposite, mating, electrode;

removing an existing welding cap from the electrode tip to expose the frusto-conical member;

seating the tool on the exposed frusto-conical member; and

rotating the tool about the frusto-conical member, thereby honing the frusto-conical member.

13. The method of claim 12 wherein, after the step of seating and before the step of rotating said method further includes the step of closing the electrode relative to the opposite, mating, electrode.

14. The method of claim 13 wherein the tool has a second seat, and the step of closing includes seating the opposite electrode in the second seat whereby the tool is stabilised relative to the axis of the frusto-conical electrode member.

15. The method of claim 12 wherein said method includes removing the tool, reversing the tool and honing a corresponding frusto-conical member of the opposite electrode as well.

16. The method of claim 14 wherein said method includes removing the tool, reversing the tool and honing a corresponding frusto-conical member of the opposite electrode as well.

17. A tool for dressing a nominally frusto-conical member, the frusto-conical member having a pre-determined design taper, wherein:

said dressing tool has a body, one of

(a) where the frusto-conical member is a male part, an accommodation, said accommodation being formed to receive said male frusto-conical member therewithin and to permit rotation of said body about the frusto-conical member when so received, said accommodation having a dressing member for engagement with the frusto-conical member, said dressing member having a taper angle corresponding to said design taper of said frusto-conical member;

(b) where the frusto-conical member is a female part, a protrusion, said protrusion being formed to engage the female frusto-conical member therewithin and to permit rotation of said protrusion within the female frusto-conical member when so received, said protrusion having a dressing member for engagement with the frusto-conical member, said dressing member having a taper angle corresponding to said design taper of the female frusto-conical member;

said body having a torque input interface by which, in use, said tool may receive an input torque to cause said tool to turn relative to the frusto-conical member, and in so doing to cause said dressing member to hone the frusto-conical member; and

said dressing member includes a region of abrasive grit.