REFLECTOR: Adjustable Seat Back Hinges

Sat Aug 11 21:17:15 CDT 2007

I took our seats with new adjustable hinges down to Sebastian a few weeks
ago.  Dwayne looked at them and we decided there were a couple of problems.
The first fix was to get rid of the two front seat backs (that came with our
kit nine years ago) and replace them with two rear seat backs - which have
less 'toe-in' angling at the bottoms than the original front seat backs.
The newer kits are now shipping with (4) rear seat backs.  This helped
reduce binding as the seats are folded forward.  

We also added ~1/8" shims between the lower arms of the seat hinges and
where they attach to the seat bottoms.  This helps keep the outer arms of
the hinge that attach to the bottom more out of the way of the upper arms
(which attach to the seat backs) as the seats are folded forward.  The basic
problem is that the sides of the seat bottoms angle out slightly to match
the angling in of the bottom portion of the seat backs - which makes them
align perfectly with the seats back, but when you rotate the seat backs
forward, then (even with the bending Scott mentions) the tops of the hinges
are no longer in the plane of the bottoms of the hinges and binding occurs.
(Notice in the photo below the two arcs where the metal of the inner hinge
has been scraping the metal of the outer hinge).  Despite this, the two
fixes above will allow the seats to fold full forward with little binding -
provided you use the old seat hinges!  

There was still another issue with the new adjustable seat hinges, one that
I consider a significant safety issue with the front seats and a major
inconvenience for the rear seats.  As we received them from the factory, the
adjustable hinges are machined with a 'protruding corner' between the full
back and the full forward positions.  This protrusion will not allow the
seat back to be moved from the full back position to the full forward
position without also turning the seat adjustment lever forward
simultaneously.  This is awkward if you're trying to lower the rear seat
backs to put bags on the baggage shelf.  More seriously, I believe this is a
safety of flight issue for the front seats.  In an emergency egress
situation, you wouldn't be able to just push the front seat backs, but
instead would have to also turn the adjust lever simultaneously.

It may be that this is just a manufacturing defect that has crept in as the
new adjustable seat hinges moved into 'mass production'.  However, for us,
rapid egress from the rear seats in an emergency situation was an important
enough requirement that we modified the hinges so they can be just pushed
from the full back to the full forward position (without any need to also
turn the position adjusting knob).  The BLACK line (toward the center
bottom) of the photo above shows the original shape of the inner adjustable
seat hinges as we received them.  The black corner just below the hinge bolt
binds on the adjustment cam and is what prevents moving the seat backs
forward without simultaneously turning the adjustment knob.  The RED line
shows what we cut away from the inner hinge (on both sides) to allow 'one
hand' operation of the seat forward movement.  The slight rounding of the
cut line and the removal of the additional section of the inner hinge allows
it to move down to become nearly horizontal and automatically turns the seat
adjustment cam slightly as you push the seat back forward.

Hope this helps,

Bob Jackson

1998 XLRG

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Baker
Sent: Wednesday, August 01, 2007 11:47 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Adjustable Seat Back Hinges

Bend the end of the hinges so they come in contact with the seat back.

The hinge, at the pivot point, remains parallel.

The seat back tilt works okay and does not bind.

SB

----- Original Message ----- 

From: Lawrence <mailto:ljepstein at hotmail.com>  Epstein,MD 

To: 'Velocity Aircraft <mailto:reflector at tvbf.org>  Owners and Builders
list' 

Sent: Wednesday, August 01, 2007 11:11 AM

Subject: Re: REFLECTOR: Adjustable Seat Back Hinges

Was there an answer to this that I missed?

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Bob Jackson
Sent: Sunday, July 15, 2007 12:02 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: REFLECTOR: Adjustable Seat Back Hinges

I recently bought the new adjustable seat back hinges from Velocity, but
have had difficulty getting them installed in a way that makes them operate
smoothly or freely.  Understanding that they are designed not to mount
directly against the seat bottom and back pans (but instead with the seat
fabric and a little bit of foam trapped in between), we have tried using
shims to simulate the thickness of the fabric and foam.  But even so, we
have still been unable to install them so that they operate smoothly and
freely or to allow the front seat backs to be easily folded down nearly on
top of the seat bottoms for easy ingress to the rear seats and for the easy
storage of bags behind the rear seats.

The basic problem seem to be the fact that the lower part of the seat backs,
where the hinges attach to the embedded hardpoints, are not parallel which
angles the two hinge axes and prevents them from being co-linear, as shown
in the photo below:

The angling also causes the seat tilt rod to bend and not operate smoothly.
The adjustable seat hinges seem like a good idea, but we have been unable to
install them properly.

The question is whether or not someone on the Reflector has been able to
successfully shim the hinges to allow the seat back to move smoothly and
easily through it's full range of tilt forward motion, and if so, how they
did it.

Any ideas or suggestions from people who have made them work would be
appreciated,

Thanks,

Bob Jackson

XLRG

  _____  

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