Weight a Minute

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A lot of product reviews on the Web make a point of the ClamCase’s weight as being a “minus” factor. At 1.5 pounds (about two-thirds of a kilo), the ClamCase is indeed among the heaviest of its competitors in the same price level.

What most people don’t know, is that the ClamCase’s weight is an important component of its design.

A Matter of Balance

Designed to act like a laptop or ultrabook when combined with an iPad, ClamCase follows the design principles obeyed by these clamshell devices. The number one consideration is that a laptop or any clamshell device should not tip over when opened for normal use and placed on a flat surface.

Every object has a center of gravity or point of balance. This is the point (within the space occupied by an object) where all its weight seems concentrated. An object is stable when this imaginary point lies within the footprint of the object’s supporting base (actually the area covered by the points in contact with whatever flat supporting surface is underneath the object). When this point goes outside the base’s footprint, the object tips over.

Object tips over when center of gravity (CG) passes pivot point. (Image from the School for Champions website. http://www.school-for-champions.com/science/gravity_center.htm)

Applying this principle to clamshell devices like a laptop, notebook or ultrabook, and the ClamCase (let’s take this ClamCase Trooper) as an example:

Keyboard/base is heavier than screen/iPad (center of gravity is inside the coverage of the base):

CG is inside the base support area: clamshell device is stable

Keyboard/base is lighter than screen/iPad (center of gravity is outside the laptop’s footprint):

CG is outside the base support area: clamshell device is unstable

Device tips over:

Clamshell device (or laptop) tips over

Which means the ClamCase, by design, should be heavier than an iPad, to counter the iPad’s weight, and “pull” their center of gravity together inside the ClamCase base’s footprint.

Achieving Balance

To prevent tipping over, clamshell devices (including laptops) should have their center of gravity within the area covered by the base. There are two ways to achieve this.

  1. Make the base heavier than the screen component (iPad in case of clamshell keyboard cases). This area covered by this base is limited by the base’s length and width.
  2. Support only the iPad’s center of gravity by placing a buttress at the back, like what’s done with table picture frames (or Medieval cathedrals, for that matter). Since the keyboard case is no longer concerned with pulling the weight of the iPad, the case can be as light and thin as it wants.

Of the two, only the first option is available to clamshell devices like laptops, netbooks, and keyboard cases like the ClamCase.

iPad stand/cases having back supports effectively increase their base support area, and can afford to be lighter than iPads as a result. If the ClamCase Pro is as light as this Belkin Ultimate keyboard case, at 0.91 pounds (411 grams), it won’t be able to pull the iPad’s center of gravity inside its support base area:


If the ClamCase were lighter than an iPad (like a thin competitor), the iPad’s center of gravity would be outside the base and it would tip over.

The Weight of the Matter

So, by necessity, any clamshell keyboard case design (even if not a ClamCase) will always be heavier than an iPad. (Unless you add an unsightly stand at the back of the screen – whoever heard of a laptop with such a stand?)

The latest iPads weigh 1.44 to 1.46 pounds (the latter with the cellular function). The ClamCase Pro is 0.85 inches thick and weighs 1.5 pounds, just 0.04 pounds heavier than an iPad. “Most 13.3 inch ultrabooks are about 0.7 – 0.8 inches thick and weigh around 3 pounds.” With an iPad (cellular) attached, the ClamCase Pro weighs 2.96 pounds – only slightly thicker, but weighs like an average ultrabook.

In the end …

Choosing ClamCase over a lighter, thinner alternative depends how you would want to use a keyboard case. As this Macworld iPad keyboard buying guide says:

iPad keyboards are exercises in compromise. You need to decide which compromises are best for you.

If you only like basic keyboard and stand functions and not the feel of an ultrabook, maybe the lighter, thinner alternatives (that don’t offer much protection) are better for you. If you like a solid, dependable, ultrabook-like keyboard case that also doubles as a sturdy all-angle base for media viewing, the ClamCase or ClamCase Pro is your best choice.