Stamped dual snowmobile runner and method of manufacture

Abstract

A runner and method of making a runner for mounting on a snow ski including a runner body fabricated of one piece of stamped metal which includes a central base portion and a pair of longitudinally extending runner portions which are bent downwardly from the base portions in laterally spaced relationship to one another. Carbide wear strips are secured to the lower edges of the runner portions, while the base portion 18 is fitted with mounting structure 48 which extends upwardly from the base portion and does not extend into the channel 36 . The mounting structure 48 may be formed as one piece with the runner body 16 of the same material, has one or more tab features, and may be threaded and/or pierced to accommodate an associated net or mounting pin as desired for mounting the runner.

1 . A traction increasing runner for mounting on the underside of a snowmobile ski, comprising:
 a runner body fabricated of one piece stamped metal having a predetermined hardness, a central base portion having upper and lower faces and extending longitudinally between opposite longitudinal ends and laterally between opposite sides, and including a pair of longitudinally extending runner portions provided along said laterally opposite sides of said base portion and fabricated of the same one-piece stamped metal as that of the base portion and fixed to said base portion by intervening bent portions of said runner body such that said runner portions project transversely downwardly of said base portion and terminate at lower free edges thereof and defining a generally U-shaped channel on an underside of said runner body; and   mounting structure, secured to said runner body in spaced relation to said U-shaped channel, operative to mount said runner body on the underside of the snowmobile ski.   
     
     
         2 . A traction increasing runner for mounting on the underside of a snowmobile ski, comprising:
 a runner body fabricated of one piece stamped metal having a predetermined hardness, a central base portion having upper and lower faces and extending longitudinally between opposite longitudinal ends and laterally between opposite sides, and including a pair of longitudinally extending runner portions provided along said laterally opposite sides of said base portion and fabricated of the same one-piece stamped metal as that of the base portion and fixed to said base portion by intervening bent portions of said runner body such that said runner portions project transversely downwardly of said base portion and terminate at lower free edges thereof and defining a generally U-shaped channel on an underside of said runner body; and   a mounting structure, secured to said runner body in spaced relation to said U-shaped channel, operative to mount said runner body on the underside of the snowmobile ski; said mounting structure being formed as one piece with said runner body.   
     
     
         3 . A traction increasing runner for mounting on the underside of a snowmobile ski, comprising:
 a runner body fabricated of one piece stamped metal having a predetermined hardness, a central base portion having upper and lower faces and extending longitudinally between opposite longitudinal ends and laterally between opposite sides, and including a pair of longitudinally extending runner portions provided along said laterally opposite sides of said base portion and fabricated of the same one-piece stamped metal as that of the base portion and fixed to said base portion by intervening bent portions of said runner body such that said runner portions project transversely downwardly of said base portion and terminate at lower free edges thereof and defining a generally U-shaped channel on an underside of said runner body; and   mounting structure, secured to said runner body in spaced relation to said U-shaped channel, operative to mount said runner body on the underside of the snowmobile ski—said mounting structure comprising at least one mounting tab fabricated of the same one piece stamped metal as that of the runner body projecting from said upper face of said base portion in a direction away from said runner portions.   
     
     
         4 . The runner of  claim 3  wherein said at least one mounting tab is spaced from said longitudinally opposite ends of said base portion. 
     
     
         5 . The runner of  claim 3  wherein said base portion includes a cut-out region separating edge portions of said at least one mounting tab from said base, and wherein said mounting tab extends upwardly away from said cut-out region and is joined to the base portion by a bent base end of said at least one mounting tab. 
     
     
         6 . The runner of  claim 5  wherein there are a plurality of said mounting tabs. 
     
     
         7 . The runner of  claim 3  wherein said at least one mounting tab includes screw threads. 
     
     
         8 . The runner of  claim 3  wherein said at least one mounting tab is formed with an opening adjacent a free end thereof for receiving a fastener. 
     
     
         9 . (canceled) 
     
     
         10 . A traction increasing runner for mounting on the underside of a snowmobile ski, comprising:
 a runner body fabricated of one piece stamped metal having a predetermined hardness, a central base portion having upper and lower faces and extending longitudinally between opposite longitudinal ends and laterally between opposite sides, and including a pair of longitudinally extending runner portions provided along said laterally opposite sides of said base portion and fabricated of the same one-piece stamped metal as that of the base portion and fixed to said base portion by intervening bent portions of said runner body such that said runner portions project transversely downwardly of said base portion and terminate at lower free edges thereof and defining a generally U-shaped channel on an underside of said runner body; and   a mounting structure, secured to said runner body in spaced relation to said U-shaped channel, operative to mount said runner body on the underside of the snowmobile ski; said lower free edges of said runner portions being formed with a notch recessed into said runner portions from said lower free edges, and said wear strips comprising carbide wear bars disposed in said notches, said carbide wear bars being the same width as the lower free edges of the runner portions.   
     
     
         11 . The runner of  claim 3  wherein said mounting tabs and said base portion have the same thickness. 
     
     
         12 .- 17 . (canceled) 
     
     
         18 . A method of fabricating a runner for mounting on the underside of a snowmobile ski, comprising:
 preparing a single generally planer sheet of metal material having a predetermined hardness, a generally uniform thickness and upper and lower faces;   separating a shaped workpiece from the planer sheet;   bending predetermined runner portion side regions of the shaped workpiece out of the plane of the workpiece to extend the runner portions downwardly from laterally opposite sides of a central longitudinally extending base portion of the workpiece and defining a generally U-shaped channel on an underside of the workpiece; and   forming mounting portions on the base portion that project upwardly from a top side surface of the base portion and which do not extend into said U-shaped channel.   
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 19  including securing a hardened wear strip having a hardness greater than said predetermined hardness of said metal material in each of the notches. 
     
     
         21 . The method of  claim 19  wherein the notches are formed prior to bending the runner portions. 
     
     
         22 . The method of  claim 21  wherein the notches are formed during the separation of the workpiece from the sheet. 
     
     
         23 . The method of  claim 19  wherein said hardened wear strips are secured to the runner portions following the bending of the runner portions. 
     
     
         24 . The method of  claim 19  wherein said hardened strips are secured to the runner portions before the runner portions are bent. 
     
     
         25 . The method of  claim 19  wherein said hardened wear strips comprise carbide wear strips secured with a metallic bond by heating said workpiece and said carbide strips to an elevated bonding temperature, after which the united workpiece and carbide strips are quenched at a controlled rate to generate a hardness of the workpiece material of between about 45 to 65 Rc. 
     
     
         26 . The method of  claim 25  wherein the workpiece is fabricated of SAE 1045 plain carbon steel. 
     
     
         27 . The method of  claim 18  including forming the mounting portions by isolating a mounting tab region of the base portion and then bending the mounting tab region upwardly out of the general plane of the base portion. 
     
     
         28 . The method of  claim 27  including forming a plurality of the mounting tab regions. 
     
     
         29 . The method of  claim 28  including forming thread regions on the tab regions. 
     
     
         30 . The method of  claim 27  including forming a hole in each of the mounting tab regions. 
     
     
         31 . The method of  claim 28  wherein mounting tab regions are isolated by cutting a U-shaped notch in the base portion to partially separate the mounting tab regions from the base portion along the notches. 
     
     
         32 . The method of  claim 31  wherein the notches are formed during the separation of the workpiece from the sheet. 
     
     
         33 . The method of  claim 18  wherein the mounting portions are formed by welding threaded studs to an upper surface of the base portion. 
     
     
         34 . The method of  claim 18  including bending a forward end of the base portion upwardly out of the general plane of the base portion. 
     
     
         35 . The method of  claim 18  including forming tapered regions of the runner portions on forward and rearward ends thereof. 
     
     
         36 . The method of  claim 18  including forming longitudinally staggered notches in the runner portions and securing carbide wear strips in the notches. 
     
     
         37 . The method set forth in  claim 18  wherein said separating step comprises stamp cutting the shaped workpiece from a planar sheet of metal to provide a flat blank of metal including said central longitudinally extending base portion and said runner portion side regions on laterally opposite sides of said base portion. 
     
     
         38 . The method set forth in  claim 37  wherein said step of stamp cutting includes concurrently stamp cutting a notch in a laterally outer edge portion of each of said runner portion side regions. 
     
     
         39 . The method set forth in  claim 38  wherein said step of stamp cutting a notch includes the step of longitudinally staggering the notches on laterally opposite sides of the metal blank. 
     
     
         40 . The method set forth in  claim 39  wherein said bending step is accomplished by folding said runner portion side regions in opposite directions out of the plane of said base portion to confronting positions. 
     
     
         41 . The method set forth in either of  claim 38 ,  39  or  40  including the step of securing a hardened wear strip, having a hardness greater than said predetermined hardness of said metal material, in each of said notches. 
     
     
         42 . The method set forth in  claim 37  wherein said stamp cutting step includes cutting said runner portion side regions with opposite edges initially lying in the same plane, and include forwardly converging forward edge portions and rearward converging rear edge portions. 
     
     
         43 . The method set forth in  claim 42  wherein said step of cutting includes cutting a notch in said side edges interadjacent said forwardly converging forward edge portions and said rearwardly converging edge portions. 
     
     
         44 . The method set forth in  claim 37  wherein said step of stamp cutting includes cutting said flat blank of metal such that said base portion includes a rear base portion, having a predetermined width, disposed between said runner portion side regions and a forward edge nose portion having a lesser predetermined width projecting forwardly of said runner portion side regions. 
     
     
         45 . The method set forth in  claim 44  further including the step of upwardly bending at least the terminal end portion of said nose portion relative to said rear base portion. 
     
     
         46 . A method of fabricating a runner for mounting on the underside of a snowmobile ski, comprising:
 stamp cutting a shaped workpiece from a planar sheet of metal having a predetermined hardness, a generally uniform thickness, and upper and lower faces to provide a flat stamped blank having a longitudinally extending central base and laterally opposite side edge portions on laterally opposite sides of said base;   said stamp cutting step including cutting said laterally opposite side edge portions with curvilinear forward and rearward edge portions extending forwardly and rearwardly, respectively, of an intermediate edge portion;   said stamp cutting step further including cutting a notch in each of said intermediate edge portions; and   folding the laterally edge portion in opposite directions out of the plane of said base to confronting positions on the underside of said base.   
     
     
         47 . The method set forth in  claim 50  wherein said stamp cutting step includes cutting said notches in longitudinally staggered relation to each other. 
     
     
         48 . The method set forth in  claim 46  wherein said curvilinear forward edge portions on opposite sides of said base forwardly converge. 
     
     
         49 . The method set forth in  claim 48  wherein said curvilinear rearward edge portions on opposite sides of said base rearwardly converge. 
     
     
         50 . The method set forth in  claim 46  including the step of forming mounting portions on said base that projects upwardly from said upper surface of said base. 
     
     
         51 . The method set forth in  claim 46  wherein said stamp cutting slip includes cutting a U-shaped notch in said base to partially separate a mounting tab portion from the base along the notch, and said step of forming mounting portions includes upwardly bending said mounting tab portion out of the plane of the base. 
     
     
         52 . The method set forth in  claim 48  further including the step of disposing a hardened wear strip, having a hardness greater than said predetermined hardness, into each of said slots and metallurgically bonding said wear stamp in said slots to said runners. 
     
     
         53 . A runner for a snowmobile ski, comprising:
 a runner body having a central base portion and a pair of runner portions fabricated of a single piece of metal of a predetermined hardness and bent to a generally U-shaped configuration such that the runner portions project transversely of the base portion and terminate at free edges;   hardened wear strips having a hardness greater than said predetermined hardness, secured to said lower free edges; and   mounting structure formed as one piece with said runner body out of said central base portion and operative to secure said runner to the ski.   
     
     
         54 . The runner of  claim 53  wherein the mounting structure comprises mounting tab portions bent upwardly from the central base portion away from said runner portions 
     
     
         55 . The runner set forth in  claim 54  wherein said mounting tab portions and said base portion are of equal thickness. 
     
     
         56 . The runner set forth in  claim 55  wherein said mounting tab portions are flat and have screw threads. 
     
     
         57 . (canceled)