Andrew Thanks for your considered thoughts on the vertical roll cage mounting points. I understand your points.
The guts of the issue is whether the compressive forces acting on a relatively small area of the floor pan (50 by 75mm) which is only thin metal, would be more likely to rip through the floor before the same forces acting through 4 high tensile bolts under shear pressure, snapped them. As a mechanical engineer do you have any info on the likely stronger scenario? I have always felt that bolting to the thinnish flat floor plate isn't that strong a mounting point. Bolting to a curved section, like the wheel well, always seems to have much more strength. ----- Original Message ----- From: "GREENBURY, Andrew Robert" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, 7 July 2002 16:49 PM Subject: Re: roll cage in 1600, mounting locations > hi Richard, > > Interesting idea. To my mind, in a roll over with a cage with floor > mounts, the loads would be transferred in a direction generally along the > cage legs, and distributed over the mount area normal to the legs in a > compressive manner. Because the majority of the load transfer to the rest > of the car would be in this manner, the affixing bolts arent put into > tension or anything, and so would do little more than locate the mounts, > and maybe some shear transfer due to force transfer not being directly > along the cage legs etc. > > However, in the same rollover scenario with vertical mounts, the force > transfer from the cage to the car will be in shear as you pointed out, but > limited by the capabilities of the bolts. Remember stress=force/area; a > fat man lying on a bodyboard probably has more chance getting across a > frozen lake than a small lady wearing high heels, because her small weight > is distributed over tiny areas. > > In the worst case the transfer would only be through the combined small > cross sectional area of the bolts (high stress concentration), best case > would be this area plus some of the mount area (again limited by the > bolts putting the mounts in tension). > > Just my thinking out loud - anyone got any views? > > Andrew > > On Fri, 5 Jul 2002, Richard Clough wrote: > > > Can anyone think of a reason why roll cage mounting brackets could not be > > installed vertically along the inside of the door sills rather than on the > > floor? > > > > My idea is to make a long mounting plate and weld it to the inside of the > > sill, or inside the sill cavity when the outer sills are replaced. This > > would allow for the forward bars in the footwell and the centre hoop to be > > mounted off the bottom of the wall rather than to the floor. > > > > My feeling is that these vertical roll cage mounts would have some > > advantages. They would be stronger than floor mounts in a roll over, as the > > forces would be shear forces rather than flat fronted forces on a thin metal > > floor pan. The full length side bars would stiffen the body. There are no > > bolts protruding under the floor getting damaged, and no problems fitting > > carpets or concealing holes in the floor if the cage is removed . > > > > Comments on this idea? > > > > ----- Original Message ----- > > From: "James Morrison" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Friday, 5 July 2002 12:30 PM > > Subject: Re: roll cage in 1600, pedal locations > > > > > > > my mates 1600 rally car has a full cage and stock pedal and yeh its pretty > > damn close to the cage, could get annoying. You may wanna think about a > > bluebird (i think) pedal and cable accellator. > > > > > > James > > > > > > --- JUSTIN FRIEDRICHS <[EMAIL PROTECTED]> wrote: > > > >Guys, > > > >Do you need to modify the position of the acc pedal > > > >and brake pedal when a roll cage is fitted to a 1600. > > > >Cos I think the cage legs need to be very close to the > > > >acc pedal. > > > > > > > >Cheers > > > >Justin > > > > > > > >http://www.sold.com.au - SOLD.com.au > > > >- Find yourself a bargain! > > > > > > > > > > _____________________________________________________________ > > > Get Your free Ozdat Email Account > > > ---> http://www.ozdat.com > > > > > > _____________________________________________________________ > > > Promote your group and strengthen ties to your members with > > [EMAIL PROTECTED] by Everyone.net http://www.everyone.net/?btn=tag > > > > > > > > > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
