Monday, 17 December 2018

Schoolboy Physics

Jan mentioned the excessive heat from the sun on the northern side of the pergola several months ago and so whilst we had the borrowed trailer it seemed like a good idea to purchase shade cloth and some timber to make a screen over the affected area.

Whilst I measured the area Jan painted the 70x30mm timber which I planned to use as rails.  Once the paint was dry I cut a 40deg bevel on one edge.  The larger part of the timber was then screwed to the side of the pergola steel top plate and the smaller portion nailed to the existing 4x2 horizontal timber at the top of the fence.

The next step was to screw the shade cloth fixing strips.  Each one is 600mm long and has barbs to secure the cloth. 

IMG_3153IMG_3154IMG_3156 If I’ve measured the bevel angle correctly the upper and lower line of retaining hooks should be on the same plane.

IMG_3157 It was then a case of attaching the shade cloth to the hooks making sure everything was smooth and taunt. At this stage the job is 80% complete.  I need to make some timber framing for each end which will run between the upper and lower ends.  This will stop the ends of the shade cloth from fraying and flapping in the wind.  I plan to cut off the surplus shade cloth at the bottom on the fence side folding the edge up and then screwing some timber capping over it to make everything secure and tidy.

The other task is the installation of the trailer battery.  My days of using brute force to lift and move heavy objects are over.  I’m reverting back to schoolboy physics using the principle of levers or ‘turning moments around a point’.

The first step has been to remove one of the long timber bearers from the garden edge and lay it under the trailer.

IMG_3158 The plan is to raise the battery into position using a “see saw” motion.  I’ll place two tiers of old bricks under the far end of the plank, then position the battery in the middle of the plank directly under the position it needs to be secured on the trailer.  I’ll then use the car jack to raise the near end of the plank.  Once the plank is parallel with the bricks at the far end I’ll stop jacking and place two tiers of bricks directly under the battery.  Then I’ll lower the jack end and place another two tiers of bricks under the far end.  I’ll repeat this cycle until the battery is in position under the trailer and ready to have the securing bolts installed.  It will be interesting to see if the plan works.  


Mike Griffin said...

Reminds me of my dear old long departed Dad's stock RAF answer to any question asked during WW2 - How would you achieve/move/lift that - the answer was always 'with a suitable arrangement of levers and pulleys Sir', Sadly 55000+ of them never lived long enough to see whether it worked.

Tom and Jan said...

Hopefully mine will Mike