A disabled relative needed a doorstop so they can walk through doorways keeping both hands on a walking frame or sitting in their wheelchair.They need to be able to move it without bending. It had to be lightweight so they could move it to and from the door.

We didn't find anything in disability catalogues or shops that would cater for their needs. The physiotherapists could not suggest anything light enough for them to be able to use. and individual expert engineering advice would cost too much. Major house modifications are beyond their budget.

We realised that a wedge would be the lightest item that would work, but how to make sure it always faced the right way so it sat under the door. I had made lightweight structures before and know how strong they can be even when they look flimsy. And so the Conical Doorstop was conceived.

The advantage of a cone is that it looks the same from whichever side you look at it when it is sitting on its base. You therefore don't have to be fussy putting ot on the floor; it will always present a wedge shape to the door.

This one is used on a door that has rising butt hinges; they automatically close the door. But most of the time we want it open.

Supplies

Cardboard for the cone
String to enable lifting it

Tools:

Round plate or dish. I used an eight inch diameter plate.
Ruler
Pencil
Scissors
Stapler with staples

Step 1: Collect Supplies

The box I used was a corn flakes packet.

The string was thin and smooth. Some string such as sisal is rough and can cut the skin of children and the elderly.

Step 2: Collect the Tools

Step 3: Prepare the Parts

Open the box by sliding your fingers along the glue lines. You might want to use a flat blade to do this if the glue is tough. Then lay it out flat on your workspace.

Now for the fun...

Step 4: Shape the Cardboard

First mark the shape for the cone on the cardboard:

Place the cardboard on a flat surface.

Place the plate upside-down on the cardboard between the folds. If it is too big try to position it so there is a minimum of it going over them.
Draw round the plate with the pencil.

Next cut the cardboard with the scissors(no picture):

snip as close to the pencil line as possible
Cut a little at a time using short snips.
Only use the tip of the scissors as this will reduce the amount that you bend the edge of the circle.

Put all the cardboard to one side except the circle.

Step 5: Cut the Circle From Circumference to Centre

Get ready to cut to the centre of the circle. You will need to draw a line from the outside to the centre of the circle (a radius). As you did not use a pair of compasses to draw the circle there is no mark where the centre should be. So do the following.

Place the ruler across the top of the cardboard with the zero mark on the left edge of the circle.( or the right edge if you prefer)
Keeping the sero mark in the same place, slide the other end of the ruler until it shows the maximum that it can, This may be somewhere a fraction more than the true diameter of the plate. It all depends on how close you drew the line round the plate and how accurately you cut along it.
Note the measurement and divide it by two. Draw a short line against the ruler both sides of this measurement.
Turn the cardboard through 90 degrees(a quarter of a turn). You do not need to do this exactly.
Repeat steps 1 to 3 so that you have two lines that cross at right angles near the centre of the cardboard.

Let's see how well you did that. Turn the cardboard through 45 degrees. Thar is half the amount you did in step 4.

Repeat steps 1 to 5. You will now have 4 lines that cross each other. Congratulations if they all cross at the same point. If they did not, DO NOT WORRY. You will have drawn a little shape at the centre of the circle, If they are less than a half inch apart it is OK. If they are further apart you might notice that the cone is lop-sided, but it should still make a usable doorstop.

Make a pencil mark as close as you can to the middle of the shape you drew and draw a straight line from it fo the circumference

If you did use a pair of compasses you can simply draw a straight line from anywhere on the circumference to the mark the compasses made at the centre.

Now cut along the line from edge to the centre.

You are now ready for the exciting bit...

Step 6: Conify Your Cardboard

(Ok that might not be a real word, but it's what we are going to do.)

We need to make the cone tall enough so it doesn't fit under the door but low enough so that the bottom of the door will hit the cone about two thirds up it So do the following until you think the cone is the right height.

Measure the distance between the door and the floor (the door gap).
Hold the two edges of the cut cardboard and pull one side over the other. This is when the magic starts and the cone begins to get taller. The more you make the edges overlap, the taller the cone will be and the steeper its sides. The flatter the cone is, the more the door will push it down onto the floor,
Estimate or measure how tall the cone is. When you think it is about one and a half times taller than the door gap, mark the underneath part with the pencil and clip one staple through both parts. The cardboard will stay in a cone shape after you let it go.
Put the cone on the floor and move the door until it just touches the cone.
Is the door touching less than halfway up the cone? Unclip the staple and repeat steps 1 to 4 without pulling the sides of the cut so they do not overlap as much.
Is the door touching more than two thirds up the cone? Unclip the staple and repeat steps 1 to to 5 pulling the sides of the cut so they overlap more.

Your cone should now be the right height to hold the door in any position without the door spoiling its shape.

Step 7: Make It Easy to Move the Doorstop

Because the cone is so light nearly everybody will be able to lift it. The following steps will make it available to everybody without bending or using a grabstick.

slide one end of the string from above the cone through the slot between upper and lower parts.
turn upside down and tie a couple of knots in the end of the string to make it fat.
hold the end of the string close to the circumference of the cone and near the outer edge of the top edge of the radial cut in the cone.
staple so the string is sandwiched tightly by the two edges of the cardboard. Try to get the prongs of the staple either side of the string so it is held more securely.
Repeat stage 4 several times, moving the staple gun further towards the summit of the cone. slide the string further up towards the summit so it pops out at the very top,
staple the two halves of the overlapping cardboard a few more times, spreading the staples over its area.

Put the doorstop on the floor and hang the string loosely over the door handle. pass it over the face of the door to the other handle and back again. This gives enough slack so you can put the doorstop on the floor where you want it before swinging the door to. This so you can half-close the door to cut out some light, allow a cooling breeze or hide from nosy neighbours.

When you want to allow the door to open or close with no restriction loop the string backwards and forwards between the handles until the doorstop no longer reaches the ground

So now we have a very lightweight doorstop that lets us hold the door open as much as we want and it is easily moved without bending. And while you are at it, why not make two so you can put them on opposite sides of the door? Then you can open it as much as you want and the wind won't blow it into a different position.