My daughter competes for the local Athletics Club and they needed a cover for the Pole Vault Mat. The mat was kept in pieces in a shipping container and rarely came out as it took over two hours to move it to the track and assemble it.
The club decided to purchase a cover so that the mat could remain on the track. The cover was required to keep the mat dry and to prevent vandals from damaging the mat. They were quoted £12,000 for a cover and I said that I could make one for less...
The problem was that the mat was very large when assembled (8m x 5m) and the cover needed to be easily removed / replaced and robust against attack!
50mm x 2mm (2") Box Section Steel - For the frame
4mm Steel Plate - For the castors to bolt to
12 Heavy Duty 8" Poly Wheel Castors
Box Profile Polyester Coated Steel Sheet
22mm Stitchers - To attached the sheet to the frame
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Step 1: Step 1 : Design the Frame
I wanted the Pole Vault Cover to match the existing smaller High Jump Mat Cover that the club owned.
I used this cover as a starting point for my design.
The critical dimensions where the size of the mat and the height and turning circle of the castors.
I decided to make the frame from 2" Steel Box section.
The above sketches are for one cover (5m x 4m), I made two of these and pushed them together over the mat.
I designed it to have only 1" clearance off the ground as it was rolling on the jump apron which was flat.
Step 2: Step 2 : Build the Frame
Using a chop saw I cut the box steel to length.
I butt jointed the intersections rather than mitering them to save time, ends of some tubes were left open, see galvanizing.
I welded the frame together to build the components with a small arc welder using 2.5 mm rods.
The welder had a habit of over heating,so i ran a fan next to it to blow air through it!
The sides are wide to allow the castors to turn 360 deg without hitting the outside of the cover or the mat.
The 4 mm plate was cut for the castors to attach to with an angle grinder
I tried to put the 90 deg bend in the 4 mm plate myself but couldn't bend it, so I had to take it to a local company to fold it.
Step 3: Step 3 : Coat the Frame
I took the fabricated frame parts to a local company to have them galvanized to prevent them rusting.
It is important to ensure that there are no enclosed chambers in your project as they could explode in the tank!
I had to drill 10mm holes at all ends of closed chambers.
A representative from the Galvanizing company visited me to check that I had vented the steel correctly before I took it to their plant.
There was useful guidance on the Galvanizing company website;
To achieve the best quality zinc coating, it is important to ensure that the molten zinc can flow freely over all surfaces, external and internal. So, where there are sealed hollow sections or cavities, vent and drain holes are essential. When adequately sized and correctly located, these holes will:
- Allow faster immersion and withdrawal speeds which will help to minimise excessive coating build-up and reduce the risk of distortion by minimising temperature differentials.
- Virtually eliminate the risk of damage to product, plant and equipment caused by the explosive vaporisation of entrapped moisture.
- Improve the characteristics of the galvanized coating by restricting the effects of zinc solidification during drainage and reduce the mass of zinc required to achieve a good finish.
- Overall, a correctly vented product will ensure total corrosion protection, produce an optimum quality finish and reduce customers’ costs.
Step 4: Step 4 : Assemble the Frame on Site
The parts were taken to the track.
I clamped the parts together, drilled holes and then bolted them to each other
The wheels were bolted to their mounting plates
The frame went together quickly
The cover behind is the High Jump mat cover that I was trying to match
Step 5: Step 5: Screw on the Plastic Coated Steel Sheet
Screw on the plastic coated steel sheet.
It helps if you get the supplier to cut the sheets to size before delivery.
The sheets can be cut with shears or a jigsaw.
The sheets are held on to the frame with 22mm Stitchers. These screws drill their own hole, tap their own thread and create a waterproof seal - brilliant. The only down side was that I fitted hundreds of them, I used the driver shown in an electric drill to speed things up.
Add the capping pieces, fasteners and handles. The handles are plastic coated steel and designed for trucks.
The finished cover cost around £5K in parts, including expendables, transport and galvanizing.
Step 6: Step 6 : Pole Rack
I also made them a rack for the poles
This was made from 1" Box section and 10 mm bar
I painted this, in hindsight I wish I had galvanized it but the yellow finish is more attractive.
I added plastic end caps to the box section and rods
This is an entry in the