Cleveron Friction-Less Drawer

Last crawled date: 1 year, 11 months ago

Cleveron Friction-Less Drawer

Greetings GrabCAD community...

This is my first submission of "The Parcel Delivery System Challenge". Fortunately, I can still submit my ideas, since I know about the challenge only few days ago.

The basic idea to solve the major problem about the oversized package being jammed was to minimize the contact surface between the opened drawer and the drawer next above it. I use 5 small rod to accommodate that problem (as can be seen in the "cleveron #01.jpg" image). With this method, the friction can be minimized and localized in very small contact area. The friction will be localized in the surface of the rod.

For the drawer, I choose sheet metal material (stainless steel 316, 2mm thick). Compared to laminated hardboard, sheet metal is stronger so can minimize the thickness while maintain the strength. Thinner material we use, more room that we will get.

The sheet metal cover where the "friction rod" welded (spot weld-intermitten), will help to push the package if the package is a bit oversized. If the package oversized too much, and the pressure is much, it will prevent the drawer to close then the customer can choose bigger drawer. There is a spring that will open the cover automatically when the drawer pulled out. So, can operate the drawer with only one hand. There is also stopper in the back of the drawer. So, the drawer will stop slide outside the mainframe.

Here, I will try to explain how my proposed solution will solve the problems.

Problem-1
Allow the drawer to open at least 30mm, even if an oversized/expanding package is inserted.

Solution-1
The first solution can be check in the 3D model (and "cleveron #01.jpg"). I try to minimize the contact survace between the opened drawer and the drawer next upon it with 5 small diameter rods. When it closed, only the end of the rod will contacting the bottom surface of the drawer next above it. This way, the friction can be minimized and localized in very small area. The result, it will be easy to slide out.
To open the drawer at least 30mm automatically, I use "pull push" electromagnetic locking mechanism. It is commonly used in the RFID locking system, and widely available in the market, such as here (http://www.alibaba.com/product-detail/60kg-120Lbs-12vdc-or-24vdc-small_691592171.html). To open it at least 30mm, I choose 60kg electromagnetic lock. It used small amount of electricity (12V/100mA or 24V/50mA). It lock by pull the magnet with the electromagnet, and push by reverse the electromagnet polarity.

Problem-2
Maximize the size of package that can be inserted without jamming the drawer.

Solution-2
To solve this problem (to maximise the available room), I use sheet metal material. It is thin (2mm) but strong enough to hold the 5kg of package.

Problem-3
Guarantee the safety of the contents of the drawer(s).

Solution-3
I use 60kg electromagnetic locking system with push-pull feature. Its mean, to break the system need at least pull the drawer with 60kg of power. It is will be difficult since there is no handle in the drawer, and 60kg is quite heavy.
The connector of the locking system widely available in many kind of connector, including Molex Micro Fit 3.0 series connector (can be ordered in custom/preferred connector also).
Link for the electromagnetic locking system : http://www.alibaba.com/product-detail/60kg-120Lbs-12vdc-or-24vdc-small_691592171.html

Problem-4
Minimize the cost of the drawer solution in quantities of 1/100/1000 pcs.

Solution-4
For the drawer, mainly I use sheet metal. It is very easy to manufacture (cuting and bending process). And I am sure all sheet metal manufacturer will be able to handle that. I use 2mm thickness stainless steel 316. It is strong enough to hold the specified load and will be able to survive more than 8-10 years (2-3 times daily use). Its also less maintenance needed. For the framing, it is flexible. I use the stock framing (laminated hardboard). The framing can be using sheet metal and or steel/aluminum extrusion also.
I also develop custom drawer slide, which is stronger and less noisy compared to the slider that widely available in the market.

Problem-5
Allow easy and fast production and assembly.

Solution-5
The production was easy. I already modeling the drawer in sheet metal designing manner. Can generate flat pattern from the CAD model for cutting and bending purpose. The assembly was very easy as well. The stopper is different part and bolted to the drawer, so no need to access the drawer from the back if there is any problem appear.

Problem-6
Make use of widespread materials.

Solution-6
Mainly I use off the shelf part when designing the system. Fasteners, bearing, locking system, and etc.So all is "of the shelf part" except the sheet metal part, spring and the slider (the slider need CNC machining out of hardwood or aluminum).

Problem-7
Prevent the drawer from damaging itself in the case of misuse.

Solution-7
The choosen material was stainless steel, which is non-corrosive material. The bearing used also stainless steel bearing. So, it will be very durable.

Problem-8
Have a drawer load bearing capacity of at least 5kg (∽11 lb).

Solution-8
To accommodate the load, I designing the drawer with stainless steel sheet metal, so that it can hold the load. I also designing the custom slider that much more stronger and less noisy compared to the slider that commonly available in the market. However, I kept the design as simple as possible.

Thank you,
Arfi'an