Welding electrode cap

Abstract

The present invention provides a spot resistance welding electrode cap for welding two or more work-pieces together, including a substantially cylindrical body having an interior surface, an exterior surface, and a tapered interior cavity for frictionally fitting over an electrode shank. The exterior surface of the body includes a plurality of longitudinally extending depressions or flutes formed therein which provide an increased external surface area to the electrode cap, thus increasing the ability to transfer additional amounts of heat. The electrode cap further includes a plurality of fins disposed on the interior surface of the body within the interior cavity. The free ends of the fins are chamfered in order to ease the transition of coolant flowing throughout the shank proximate the electrode cap.

Claims

1. An electrode cap comprising: a substantially cylindrical body having a top domed working end disposed thereon forming an integral structure, the body includes an interior surface and an exterior surface cooperating to define an interior cavity, the body includes a lower terminus, the terminus defining an opening to the interior cavity; and an array of longitudinally extending flutes, each having a first end and a second end, formed within the exterior surface of the body and wherein the interior cavity is tapered to frictionally fit over an end of an electrode shank.

2. The electrode cap of claim 1 wherein the flutes are equidistantly and radially spaced apart.

3. The electrode cap of claim 1 wherein each flute extends from its first end proximate the working end to its second end proximate the terminus.

4. A spot welding resistance electrode cap comprising: a substantially cylindrical body having an interior cavity and a working end integrally formed therewith, the body having a lower terminus defining an opening into the interior cavity, the interior cavity terminating at the interior side of the working end, the body having an exterior surface and an interior surface within the cavity; an array of longitudinally extending flutes provided in the exterior surface; and a plurality of internal cooling fins disposed within the interior cavity and extending from the interior working end and terminating at a chamfered free end, the chamfered free end causing laminar flow of any coolant flow therepast.

5. The electrode cap of claim 4 wherein the plurality of flutes is an equidistantly and radially spaced apart array of semi-cylindrical depressions.

6. The electrode cap of claim 4 wherein each of the plurality of flutes extends from its first end proximate the working end to its second end proximate the terminus, a narrow band being defined between the second end of each flute and the terminus.

7. The electrode cap of claim 6 wherein each of the plurality of fins is equidistantly and radially spaced apart from an adjacent fin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of an externally fluted standard electrode cap in accordance with a first embodiment of the present invention;

(2) FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

(3) FIG. 3 is a view similar to FIG. 2, but showing the electrode cap thereof mounted on an electrode shank;

(4) FIG. 4 is a cross-sectional view of an electrode cap having a plurality of chamfered fins in accordance with a second embodiment of the present invention;

(5) FIG. 5 is a view similar to FIG. 4, but showing the electrode cap thereof mounted on an electrode shank; and

(6) FIG. 6 is a partial perspective view of the electrode cap thereof.

DETAILED DESCRIPTION OF THE INVENTION

(7) At the outset, it is to be noted that the present electrode caps are RWMA (Resistance Welding Manufacturing Alliance) standards compliant. The RWMA is a global industry sponsored professional society that has worked to develop industry standards governing many of the dimensional features related to electrode sizes and shapes. These generally accepted worldwide standards are designed to promote and provide for the universal application and interchangeability of weld components and consumables such as welding electrodes. RWMA replaceable electrode caps are, generally, standard compliant, replaceable resistance welding electrode caps used for, but not limited to, the high volume production of automobiles, appliances, and other durable goods.

(8) Now and with reference to the drawing, FIGS. 4-6 in particular, there is depicted therein a first embodiment of an RWMA electrode cap, generally, denoted at 10.

(9) According to this embodiment, the electrode cap 110 is shown as having a domed working end 118 integrally formed to the body 128, but other configurations may be used.

(10) As shown in FIGS. 4 and 5, the electrode cap 110 has an RWMA standard tapered internal cavity 120 and can be frictionally fitted to an RWMA standard domed nose 122 of a shank 124, similar to that described above in the first embodiment.

(11) The body 128 is provided with a plurality of internally formed fins 112 disposed on the interior surface 129b of the body 128 and a plurality of flutes 126 formed on the exterior surface 129a. This electrode cap 110 is structurally similar to the electrode cap 10 of FIGS. 1-3, with the exception of including the plurality of internal cooling fins 112. The fins 112 are equidistantly and radially spaced apart from one another.

(12) Each fin 112 has a free end 116. A chamfer 114 is formed at the free end 116 of each fin 112. The chamfers 114 are typically cold formed at the intersecting fin/cavity wall plane interfaces along the interior surface 129b of the body 128. As coolant enters the internal cavity 120 of the electrode cap 110, the chamfers 114 function to moderate and ease the directional transition of the fluid and change the coolant flow from turbulent to laminar. Each chamfer 114, preferably, has a minimum and maximum radius of from about 0.020 to about 0.120, respectively.

(13) Further, in this embodiment, as shown in FIG. 6, a plurality of flutes 126 are equidistantly and radially disposed about the exterior surface 129a of the body 128 of the electrode cap 110. The body 128 includes a terminus 131 which defines an opening 132 into the interior cavity 120. Similar to the first embodiment, a lower end 126a of the flutes 126 terminates just short of the terminus 131. A narrow band 130 is defined in the space between the lower end of the flutes 126 and the terminus 131.

(14) It is believed that, as compared to a conventional RWMA electrode cap, the present fluted, chamfered finned, electrode cap will demonstrate a 22% increase in external cap surface area with a corresponding increase in the ability to transfer additional amounts of heat through convection and a 33% reduction in mass with a corresponding reduction in the cost of materials and manufacturing.

(15) Because of the chamfered ends, the present electrode caps have improved thermal heat dissipation properties, thereby improving energy efficiency and extending the useful life of the caps, thus reducing their manufacturing cost through material reduction.

(16) Further, this finned/fluted electrode cap provides the added benefit of reducing the costs of manufacturing electrodes through a significant reduction in the amount of copper or copper alloy required for their production.

(17) Referring now to FIGS. 1-3, there is depicted therein a second embodiment of the present invention. Here, an electrode cap 10 has a substantially cylindrical body 12 and a domed working end or nose 14. The cap 10 is intended to be mounted onto an electrode shank 25.

(18) It should be noted, that the working end 14 of the electrode cap 10 is user application dependent and can take on a variety of different configurations, a domed nose being depicted.

(19) The body 12 includes an exterior surface 13a and an interior surface 13b. A plurality of depressions or flutes 16 having a first end 16a and a second end 16b are circumferentially formed about the exterior surface 13a of the body 12. The electrode cap 10 has a terminus 18. The flutes 16 extend from the first end 16a proximate the working end 14 to the second end 16b just short of the terminus 18 of the electrode cap 10.

(20) Usually, the second end 16b of the flutes 16 ends at a distance of from about 1 mm to about 3 mm above the terminus 18. A narrow band 24 is defined by a space provided between the second end 16b of the flutes 16 and the terminus 18. The narrow band 24 provides the present electrode cap 10 with additional structural support at what would be the thinnest part of the body 12 should the flutes 16 completely extend to the terminus 18 of the electrode cap 10.

(21) The flutes 16 are an equidistantly and radially spaced apart array of semi-cylindrical depressions. Ordinarily, the flutes 16 are formed to a depth of from about 0.020 to about 0.050.

(22) The flutes 16 are, typically, formed by cold forming or the like. The flutes or depressions provide a greater surface area for heat dissipation.

(23) The body 12 further comprises a tapered internal cavity 22. An opening 20 provided at the terminus 18 provides an entrance into the internal cavity 22 of the body 12. As shown in FIG. 3, the internal cavity 22 is tapered from proximate the nose to the opening 20 for receiving the mounting end of the electrode shank 25.

(24) Such shanks typically have a liquid coolant passage 26 for introducing coolant into the internal cavity 22 of the electrode cap 10, as well as a return passage 28 for recirculating the coolant. It is to be understood that the shank 25, itself, is not critical to the present invention, but that the present invention can be used therewith.

(25) It should be noted that, according to the present invention, the utilization of the chamfered fins is equally applicable to standard finned electrode caps as is the fluting. However, a fluted electrode cap having chamfered fins is the optimal electrode cap.