Video Making a seat lifter - the Pingu way
- Thread starter Pingu
- Start date
- Joined
- Apr 1, 2016
- Points
- 208
- Location
- Maybole , South Ayrshire
- Model of Z
- Z3 Individual Dakar / Orinoco Individual
Some nice work there Gary. 
.
Last edited:
Seat lifters of any kind would not puncture the floor because any load applied would be trying to lift this away from the floor pan not push it through it.
Tony.
Tony.
Now that's how it should be done, excellent work
- Joined
- Dec 8, 2011
- Points
- 145
The wedge is 3d printed.
- Joined
- Dec 8, 2011
- Points
- 145
Can you explain this?
Really? What happens in an accident?
Does the drivers mass move forwards in a head-on crash, yes? What stops that happening? The seat belt and pre tensioners which keep the driver in hes seat as the airbag deploys.
This forces the effort backwards into the seat back which would try to pull the front of the seat up from the floor.
Tony.
Does the drivers mass move forwards in a head-on crash, yes? What stops that happening? The seat belt and pre tensioners which keep the driver in hes seat as the airbag deploys.
This forces the effort backwards into the seat back which would try to pull the front of the seat up from the floor.
Tony.
- Joined
- Dec 8, 2011
- Points
- 145
There are two conditions to consider.
1) Static (just normal sitting in the seat)
2) Dynamic (the impact that you discussed)
1) The greater the surface area, the less stress is applied to the floor in the downward direction. As I use the same area as the standard seat, the static stress on the floor will be the same as OEM, except for the small additional stress induced by the 3° inclination of the stud.
2) The driver is strapped to the seat, and the driver and seat have to be retrained within the vehicle. There are five restraints, the seat belt shoulder mount, the two rear bolts, and the two front studs and nuts. Any seat lifter will add to the moment about the base of the front studs, as the lever has been lengthened. My lifters encapsulate the whole length of the stud, thus spreading the load over the length of the stud.
Are you suggesting that the force of the tensioner would be sufficient to rip the front studs out? If so, would that not strangle the occupant?
The tensioner tightens the belt by about 100mm. Pull the shoulder strap to create about 50mm of slack (with the belt locked) - that is the sort of force that would be applied to the rear of the seat. This force will be subtracted from the force of the weight of the driver and the seat moving forward. In my opinion, the net force would be forward, but only calculations with actual data would prove it one way or the other. Most of this forward force would be restrained by the seat belt mount and the rear bolts. A low speed bump that is fast enough to set off the tensioner may produce the effect you suggest.
This is why the big bolts are at the back and not the front.
The big bolts are at the back (10mm bolts in clearance size holes -10.5mm) because they hold the seat in position. However the front bolts, which prevent the seat tipping back when the occupant is restrained by the seatbelt, are 8mm mounted centrally in a 12mm hole. That bigger hole is there for a reason, namely to allow the car floor to deform without it tearing the stud off the floor in the event of an accident.. The type of lifter Southern boy sells removes the clearance between the front studs and the frame by using a 12mm sleeve nut with an 8mm thread so it's more likely to tear the stud off the floor because there is no room to allow the floor to deform. The pre tensioner is there to stop you going forwards into the airbag as it deploys.
Tony.
Tony.
Last edited: