Jan 29, 2012Science and Technology
Unspooling thread clamp: Sew with finesse

I have a confession to make -- I never learned to sew.  Perhaps I can blame this on growing up during the 50s and 60s before gender-based roles loosened up.  At least this sounds like a good excuse. Despite this basic lack of training, there periodically appear situations in which, however clumsily, I have to reattach a shirt button or tend to an incipient split on a pair of pants. 

At such times, my none-too-slim fingers seem to turn into sausages, while my carefully honed skills at fine manipulation vanish. I can barely hold the spool securely, and unspooling and cutting a length of thread seems to require invention of a new form of ballet, whose final move is dropping the spool and watching the thread spill across the floor. There is now help for myself and others who may find themselves in a similar scuffle with their inner klutz. 

US Patent 8,082,864, issued on December 27, 2011 to Jem Nich of Hong Kong, describes a new type of sewing thread spool.  When a spool of sewing thread is bought at the local department store, it generally consists of an indented cylinder (wood or plastic) wound with thread. There is sometimes a small notch in one of the edges that is meant to catch and hold the thread. The idea is that you unroll some of the thread, catch the thread in the notch and then cut the thread for use.

However, in practice it seems that as one unspools the thread, it often catches in the notch. As a result, sometimes the thread breaks prematurely, while at other times the spool is jerked from one’s hand and invariably winds up behind the leg of the sofa where only the cat can find it.  When the correct length of thread is successfully freed from the spool, a simple pull lodges the thread in the notch. With some threads more tension breaks the thread (occasionally at the notch), while with others it is necessary to cut the thread with scissors or a nearby bread knife. 

At times the thread escapes the notch during the cutting procedure, an event which can cause one to restart the entire process. Even when cutting the thread is properly accomplished, the residual length of thread held in the notch has neither sufficient length nor adequate access to make cutting the next length of thread an easy job.  Who would have thought that preparing a length of thread for sewing would be fraught with so many hazards? Well, Jem Nich’s invention offers some assistance.

Examine Figures 3 and 4 from Nich’s patent. The mode of operation is as follows: Thread is freely spooled off the spool; When the desired length of thread is freed, the thread is positioned in the thread passing notch 13; From notch 13, the thread is passed around clamp 22 and cutter 23; When tension is applied to the thread, it is cut by 23, and the remainder of the thread on the spool is held fast in 22; and, The length of thread between 22 and 23 provides easy access to the thread for cutting additional lengths of thread.

What is the result? Well, there are no protruding notches in which to catch the thread while unspooling, for one -- the thread passing notch is indented and without sharp edges. Nich’s spool also has a near foolproof thread clamp to prevent the thread unspooling without restriction, even if dropped on the floor during cutting.  Finally, there is no need for a secondary cutting tool, so that one does not need to juggle the spool, the thread and scissors -- the cut thread is always in hand, so to speak. I am sure that there is some way to achieve a sewing disaster while using Nich’s spool, but to this observer it appears to be far less likely than with a conventional spool.


Nich’s invention provides an excellent example of how a substantial and (presumably) marketable improvement on a previous invention need not involve earthshaking science and engineering.  Thread control is greatly improved, while one need not have three hands to carry out the cutting process. The differential cost of the invention would probably be very small, as the new spool end could be punched from sheet metal or plastic.


I don’t see many negative points. If there is room for a future improvement, it might take the form of ensuring that the unspooling thread is never out of control.  For example, if the thread passing notch were a hole comprising a one-way friction clamp, the thread would not unspool even if the spool were dropped midway in the unspooling process. However, such an improvement would require that either the spool end or the bobbin holding the thread be free to rotate, thereby requiring a far more complex spool, or a new thread wrapping pattern.

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