There has been a fundamental change in education in the last couple of years. It all started with Khan Academy and now with places like Udacity and MITx anyone has an opportunity to learn and achieve great things.
Udacity – The Future of Education
This is a short post to spread the word about Udacity and a new type of online education. Up until very recently all the online courses offered through various universities were recordings of professors lecturing to a group of people in an auditorium. While these kinds of online courses are obviously better than having no courses at all, the format is highly impersonal. Not only is the lecturer imparting wisdom to a group, but the online viewer becomes a mere spectator, an outsider looking in without any interaction or engagement.
A few weeks ago I signed up for the Search Engine class announced in this video without knowing what to expect. I was really hoping it would be different from all the other courses available through the many top universities and I have been pleasantly surprised, amazed even. We just finished Unit 1 with many quizzes and the first homework assignment and I can report that this class has exceeded all of my expectations! It feels like you are being taught personally by one of the best professors in the world, which of course you are… along with thousands of others.
The professor Thrun in the video highlights some differences between the traditional style of professor lecture and what they are trying to do at Udacity:
- Engagement. In the traditional style, the professor is smart and imparts his/her wisdom on the students. In Udacity, there are frequent quizzes so that students are constantly engaged. They must think every step of the way.
- Success. As this video points out, the current style will pass C and D students along to the next level despite the fact that they have not gained full mastery of the subject. At Udacity, students can take and retake quizzes until they have mastered the material. Success and mastery can be obtained by each student in his or her own time.
- Free High Quality Education.
While I recognize and appreciate what they are trying to do, what I feel most grateful for is the intimacy of the course. I feel like it’s taught for me by one of the best minds in the field. The professor teaching my class is David Evans and has proven to be one of the best educators I have ever had the privilege of encountering.
Thank you to Udacity and Professors Evans and Thrun!
Heart Rate Waterproof Measuring Apparatus
Last December I wrote a post about a new type of a heart rate monitor for swimmers invented by Hind Hobeika, an entrepreneur from Beirut. What makes her invention stand out from typical heart rate monitors is the fact that it is attached to the swimmer’s goggles, so it can measure the heart rate of the swimmer while he or she is swimming.
If you are interested in learning more about it, the US Patent Office recently published the patent application for this invention: “Heart Rate Waterproof Measuring Apparatus,” filed June 23, 2011.
A biofeedback device and the reflected infrared sensor used thereby are described herein that can be mounted on or integrated with eyewear such as swimming goggles. The biofeedback device includes a heart rate measuring apparatus comprising a reflected infrared sensor, a microcontroller comprising one or more filters and one or more amplifiers, a power source in electrical communication with the heart rate measuring apparatus, and a user interface. The reflected infrared sensor is positionable to detect heart rate from the temporal artery in the head. Heart rate is then communicated to the user by one or more tactile, auditory, or visual signal elements, such as a light-emitting diode display mounted within the goggles so as to be visible to the user while swimming.”
The Bell vs. Gray Telephone Patent Conspiracy
“Had he [Bell] been the first to invent it [telephone], is there any reason why he should not have described it in his [patent] application?” (George Prescott, Western Union’s chief engineer, ”The Speaking Telephone, Electric Light and Other Recent Electrical Inventions”, 1879)
If you read Bell’s patent application that was filed on February 14th, 1876, which was later described as the most valuable patent in history, you can’t help but ask the same question: why didn’t Bell describe the telephone in his application if that’s what he claimed he invented? Not only didn’t Bell describe the telephone, he titled it as “Improvements in Telegraphy” without mentioning a telephone whatsoever.
Elisha Gray, on the other hand, who filed a caveat on the same day as Bell, titled his application “Instruments for Transmitting and Receiving Vocal Sounds” in which he described a method “to transmit the tones of the human voice through a telegraphic circuit”, in other words a telephone.
There was a lot of controversy surrounding Bell’s patent application filed on Feb. 14th, 1876. There were claims that the crucial part of the telephone (liquid transmitter) was stolen from Gray’s caveat, added to Bell’s “Improvements in Telegraphy” patent application over the weekend of February 12th and rushed to the patent office the following morning. The way Bell’s application was filed at the patent office was highly irregular, to say the least. There were also allegations that the patent attorney firm that managed all Bell’s patent affairs, Pollok & Bailey, had an “underground railroad” to the patent office through an alcoholic patent examiner, Zenas Fisk Wilber. The list of suspicious and morally questionable events goes on and on.
What prompted my interest in the Gray vs. Bell controversy was the article by Patrick M. Boucher titled “Recent developments in US patent law.” After reading the article and a couple of follow-up books (see references below) it became obvious to me that the things that I had thought I knew about the invention of the telephone were simply untrue. Like many people I had thought that Alexander Graham Bell was the inventor of the telephone and that he filed his patent application two hours before Elisha Gray. As I learned, this was a myth.
The popular anecdote that Gray showed up at the Patent Office two hours after Bell was orchestrated by Bell’s patent attorneys (Pollok & Baiely). It was repeated over and over again by the media, numerous biographers and historians until the public began to believe that indeed Bell had filed his patent application two hours before Gray, so he must have been the true inventor of the telephone.
The most important part of the telephone invented in 1876 was the idea of the variable resistance transmitter (or liquid transmitter). To better understand how this variable resistance transmitter worked, let’s first review how the human ear works and then see how the liquid transmitter replicated this process.
When we hear sounds the following process takes place:
- Sounds waves enter the ear canal.
- Sound waves hit the eardrum (membrane), which begin to vibrate.
- The membrane vibration causes the tiny bones that connect the membrane to the inner ear to move.
- The bone movements cause waves in the inner ear fluid.
- These waves in the fluid push against another membrane with hair cells.
- The hair cells are attached to nerve fibers.
- As the second membrane moves, the nerve fibers send signals to the brain.
- The brain interprets these signals as sounds.
The variable resistance transmitter made it possible to move sound waves along an electric wire, much like the sound waves in the human ear.
The following process takes place in the variable resistance transmitter:
- Sound waves enter a metal cone.
- Sound waves hit the diaphragm at the bottom of the cone, which begins to vibrate.
- The diaphragm vibration causes the platinum needle, which is attached to the bottom of the diaphragm and dipped into the container with acid liquid, to move up and down.
- These rising and lowering of the needle into the container with liquid moved the tip of the needle closer and further from a metal contact submerged in the same container of liquid.
- The needle was connected to a battery, which created an electric circuit that was completed though the acid water to the receiver.
- The depth of the needle in the liquid and as a result the resistance of the circuit varied as the sound waves made the diaphragm vibrate.
- The receiver included a small strip of metal, which vibrated in accordance to the current.
- The sound waves traveled through the wire as “undulating current” and were heard in the receiver.
As mentioned above, this variable resistance transmitter was the single most important part of the telephone. It’s what made the telephone capable of transmitting the human voice clearly and audibly to the listener. What’s interesting is that the description of this transmitter only appeared in Bell’s lab journal 2 days after he received his famous patent. It was not in his patent application either. It was however, in Gray’s caveat that was filed 3 weeks before it appeared in Bell’s notebooks. What is really disturbing, though, is the striking similarities between the way Bell depicted his variable resistance transmitter and the way Gray described it in his caveat 3 weeks prior (the left image is from Gray’s caveat and the right one is from Bell’s notebook):
This and other evidence strongly suggest that Bell plagiarized the idea of the liquid transmitter from Elisha Gray. There were so many irregularities surrounding Bell’s telephone patent that the Assistant Secretary of the Interior George A. Jenks had this to say in the conclusion of his report regarding the 1876 patent controversy:
“If in passing through a forest the woodsman should come upon the course of a tornado, and finds the tops of the trees all pointing in one direction he would be as firmly convinced of the direction the wind had blown as though he had been an eye witness to the storm. In this one-sided contest between the Bell application and the Gray caveat the tree tops all point one way.” (Evenson 2000, p. 91)
Because there were so many people involved and so many connections between the people and the events that took place during 1875-1876, I decided to keep track of all the information in the form of a mind map, which you can view below. Even though this mind map consists of only key events, it is still a large file (>5 Mb, click the image below to view in full). I hope by examining this mind map everyone will be able to make his or her own decision about which direction “the tree tops point.”
References
______________
Evenson, Edward. The Telephone Patent Conspiracy of 1876. Jefferson, North Carolina: McFarland & Company, Inc., Publishers, 2000
Shulman, Seth. The Telephone Gambit. New York, London: W.W. Norton & Company, Inc., 2009.
Gray, Sharlotte. Alexander Graham Bell and the Passion for Invention. New York: Arcade Publishing Inc., 2006
Thompson, Silvanus. Philipp Reis: Inventor of the Telephone. London: William Clowes and Sons, Limited, 1883
Wilber, Zenas. Mr. Wilber Confesses. Washington Post. May 22, 1886. Web. January 15, 2012
Bell’s Telephone Patent. New York Times. January 28th, 1887. Web. January 31, 2012.
Bell, Alexander. Improvement in Telegraphy; Patent: 174,465. US Patent Office. March 7, 1886. Web. January 20, 2012
Stasi, Facebook and Privacy
Interesting article about privacy and Facebook:
“I still wonder why Facebook sent the file to me. Why would you send that evidence to your opponent?” Schrems compares it to the files that the Stasi compiled on citizens in East Germany. “The most prominent politicians had a thousand pages in their files,” says Schrems. “I’m just a normal guy who’s been on Facebook for three years. Imagine this in 10 years: every demonstration I’ve been to, my political thoughts, intimate conversations, discussion of illnesses.”
Analysis of the New Technical Aid Swimming Hand Paddles
The US patent office recently published a patent application for a new type of a swim paddle that I thought looked interesting. Below I will describe the claimed benefits of this paddle along with potential drawbacks and discuss how it could be simplified.
What differentiates this paddle from others is the “attached angled section, which provides instant resistive and visual feedback when a swimming stroke is not properly executed”.
“Technical Aid Swimming Hand Paddles “ by Doyle; Joseph Gordon, 2011:
Here is the background of the problem that the paddle is trying to solve as described in the patent application:
“Throughout the development of swimming stroke mechanics, it is widely accepted that a swimmer’s palm must be perpendicular to the direction of travel and pressing water in the rearward direction. If the swimmer ceases to press water in the rear direction while the hand is still in the water, then the swimmer is not increasing his or her body speed in the desired direction. If the swimmer’s hand becomes non-perpendicular to the overall direction of travel, then the swimmer will essentially be decreasing the amount of resistance at which he or she is able to push the water backwards.”
To help swimmers develop perfect stroke, the “technical aid swimming hand paddles” introduced a special flap that is attached below the paddle and that can open and close like a duck’s beak.
According to the paddle description, when the arm stroke is properly executed, the paddle stays perpendicular to the surface of the water, and the pressure of the water keeps the flap closed (the duck’s beak is closed). Here is a simple diagram to help you visualize this concept:
When the stroke is not properly executed, the paddle is no longer perpendicular to the surface of the water and the pressure of the water opens the flap (the duck’s beak opens), which immediately generates more resistance and alerts the swimmer.
There is, however another case that is not described in the patent application but is important to consider. What happens when the hand exits the water?
When a swimmer’s hand exits the water, the hand, although is still perpendicular to the surface of the water, now moves up (not backwards). During this movement, the water pressure between the “lip” and the paddle will open the paddle flap, which will generate more resistance and alert the swimmer.
Unfortunately, the very mechanism that that was designed to help swimmers develop better technique during the pull phase of the stroke will cause negative effect during the hand exit phase. The open flap will generate more resistance, which will add more pressure to swimmer’s shoulder and might hinder his or her technique.
At this point we might ask ourselves a question, can the design of this paddle be improved to avoid opening of the flap during the hand exit phase of the stroke?
The answer is yes. We can effectively implement the idea of the “visual feedback” by utilizing existing paddles. If you attach a regular paddle to the middle finger, you will essentially get exactly the same paddle as the “technical aid swimming hand paddle”, only significantly simpler.
Let’s think of the “technical aid swimming hand paddle” on a swimmer’s hand in abstract as three layers: the hand, the paddle and the flap. Again, the diagram below will help you visualize this concept:
When the stroke is not properly executed, the flap opens and generates resistance in the area between the paddle and the flap (or between the flap layer and the paddle layer). When the stroke is executed properly, the flap, the paddle and the hand all stay together (all three layers are staked on top of each other):
Now, if we look at the two images above and think of the “technical aid swimming hand paddle” in terms of layers then we can notice that the only purpose of the paddle layer is to connect the flap and the swimmer’s hand. We can also notice that the flap actually serves two purposes: to be the paddle and to serve as a visual feedback of incorrectly executed stroke.
This poses an obvious question, if the only purpose of the paddle is to connect the flap to the swimmer’s hand, why can’t we connect the flap to the swimmer’s hand directly and eliminate the paddle layer altogether? This will simplify the device without sacrificing any benefits.
As mentioned above, attaching a regular paddle to the middle finger will essentially create the “technical aid swimming hand paddle” but without the extra layer. The absence of the wrist band on the regular paddle means that the paddle can move away from the swimmer’s palm, just like the flap can move away form the actual paddle in the “technical aid swimming hand paddle.” When the stroke is not perfectly executed, the pressure of the water will move the paddle away from the palm, which will generate more resistance and alert the swimmers, again, just what the flap does in the “technical aid swimming sand paddle.”
Finally, since a regular paddle is flat and doesn’t have the “lip” that the flap on the “technical aid swimming sand paddle” has, it will not open during the hand exit phase and will not generate extra resistance and will not add extra stress to the swimmer’s shoulder.
The “technical aid swimming hand paddle” is an interesting device that has certain benefits. Unfortunately, it also has a serious drawback. In my opinion, the design is overly complicated and the goal of this paddle can be achieved by using existing paddles.
No SOPA
No SOPA
Why the U-Shaped Snorkel Has Never Been Embraced by Swimmers
A few months ago I wrote a post about the evolution of the center-mounted snorkel. Today I will look at another type of swimming snorkel, the U-shaped snorkel. Over the last hundred years many U-shaped snorkels have been invented but, to the best of my knowledge, swimmers have not embraced any of them. Below I will show a brief evolution of the U-shaped snorkel and then try to answer the question why swimmers have not adopted them as training gear.
The first device I looked at was not a snorkel per se but it had all the elements of such and theoretically could have been used as a snorkel. “Respirating Device” invented by Martin Hilgers in 1914:
The purpose of this device was to be used “while massaging the face or treating the eyes.” It had a mouthpiece, a nose clip and the means to secure air-tubes behind the ears. Even though it was not a U-shaped swimming snorkel, it could have easily become one by making the air tubes a little longer, which is exactly what Percy Greer did when he invented his “Swimmer’s Appliance” in 1928:
As you can see, the air tubes are significantly longer than in the previous device, which allows a swimmer to keep his/her head in the water and still breath. There was also a “buoyant attachment,” something like a ball, at the top ensuring that the air tubes remain clear of the water. Unfortunately, the “buoyant attachment” in this device is too large and bulky to be used comfortably by most swimmers. It would generate a lot of drag; the faster the swimmer swam, the more drag it would generate!
The 1988 invention by Donald McGilvray, “Exercise snorkel apparatus” solved the problem of keeping the air-tube tops above the surface of the water differently:
This snorkel looks a lot like the device that was described first. The air tubes curved around the face and were secured behind the ears. The tubes could either be projected upwards separately or be connected together behind the swimmer’s head.
In 1995 Glenn Albrecht invented the device shown below:
The main difference between this snorkel and the previously described ones is the flexible air tubing. Again, it had a buoyant slip piece at the top to connect (and adjust the tightness) of the two tubings together. As previously mentioned, you need the buoyant piece to keep the top of the air-tube above the surface of the water. The buoyant piece, unfortunately, was still too big.
The last snorkel I wanted to show was a recent invention that received a design patent in 2005. “Snorkel” by Mathais Weigner:
I couldn’t find any information about this snorkel. It has an interesting looking valve below the mouthpiece. This snorkel looks a lot like the “Powerbreather” snorkel, that is shown on the right, but I can’t be sure if it is actually the same snorkel. (here is a video about “Powerbreather”, if you are interested)
A lot more U-shaped snorkels have been designed in the past but most of them look similar to the ones described above and none of them have been widely adopted by swimmers. The snorkel that was adopted by most swimmers, however, was designed by Dean Garraffa in 1996 and is known as a center-mounted snorkel:
This poses the obvious question: why did the U-shaped snorkel fail and the center-mounted snorkel succeed?
To answer this question we need to first understand the minimum requirements for a swimming training device. Or to phrase it differently, we need to understand what makes a swimmer dislike a certain swimming device.
Generally, swimmers do not like to use swimming training devices that fall into at least one of the following three categories:
- A device that is uncomfortable, because discomfort will eventually hinder technique.
- A device that negatively affects swimmer’s body position in the water, because it will lead to bad habits and bad technique.
- A device that generates unexpected drag, because it might lead to discomfort, annoyance or bad body position in the water.
The last category, unexpected drag, is the least intuitive so I will briefly explain it. Every piece of equipment used in the pool generates drag to a certain degree. Some equipment is specifically designed to generate drag to make swimmers stronger and more powerful (e.g. parachutes, power tower, DragSox, etc.). Swimmers purchase these devices expecting drag and will continue to use them if the level of drag meets their expectations. On the other hand, much equipment is designed to increase a swimmer’s comfort level in the water (e.g. goggles, caps, etc) or enhance technique (e.g. snorkel). Swimmers expect these kinds of devices to generate very little drag.
Unlike parachutes, snorkels are considered a device to enhance technique and increase comfort in the water. Swimmers expect very little drag from a snorkel.
If we compare the U-shaped snorkel with the center-mounted snorkel we can see that the fundamental different between the two is the number of air-tubes. The U-shaped snorkel has two air-tubes and the center-mounted snorkel has only one. Since each air-tube generates at least some drag, the more air tubes you have the more drag they will generate.
It is possible then to assume that one of the reasons why swimmers have not adopted the U-shaped snorkel is simply because the amount of drag it generates with its two air-tubes swimmers perceive as unacceptable.
Another possible reason why U-tube snorkel failed could be explained by the position that swimmers assume when they push off the wall. When swimmers push off the wall they try to assume a streamlined position as it reduces drag and can propel them farther and faster in the water. One of the attributes of being streamlined is tightly squeezing the head between the arms (see image below):
In the streamlined position the air-tubes of the U-shaped snorkel would be between the swimmer’s head and his or her arms. Squeezing the air-tubes against the swimmer’s head would not only make swimmer’s position less streamlined (unacceptable drag) it would also make it uncomfortable and possibly painful. The center-mounted snorkel doesn’t have that problem because the air-tube curves around the forehead and between the arms in the streamlined position.
The U-shaped snorkel meets all three categories of what swimmers dislike. The tubing will hit against the head in a streamlined position causing discomfort and/or altering the swimmer’s technique, and it causes much more drag when the expectation is little drag to none. There could be other reasons for the failure of the U-shaped snorkel, but these are plenty to push swimmers away.
The Principle of Separation & the Evolution of the Steam Engine
The two most well known steam engines in the evolution of the steam engine were Newcomen’s and Watt’s engines. A lot has been written about them as the steam engine is credited for starting the Industrial revolution. What I am going to show in post is how both Newcomen and Watt applied exactly the same principle, the principle of separation, to significantly improve their steam engines over their predecessor’s.
The first known apparatus to create a vacuum by condensing steam was made by Denis Papin in the late 17th century. In 1675, Papin moved from France to London and started working under Boyle making various experiments with his air pump.
The way his contraption worked was as follows: about a third inch of water was poured into the cylinder and brought to boiling by fire under the cylinder. When the water was turned into steam it forced the piston up, which was latched at the top. When the cylinder cooled off the piston was unlatched and the pressure of the atmosphere forced it down. The thing to note is that the boiler that generated the steam was inside the cylinder.
Even though it was a great apparatus that had the key elements of the future steam engine (piston, cylinder and condensation), it needed further developments to work as a functioning, efficient engine.
Let’s skip forward to 1712 and look at the Newcomen’s engine.
Newcomen's atmospheric engine 1712
Newcomen’s engine consisted, among other things, of a cylinder, a beam, a piston, a separate boiler below the cylinder that provided steam and a valve to control access of cold water into the cylinder to condense steam. One end of the beam was connected to the piston and the other to a pump bucket.
When steam was condensed, the pressure of the atmosphere forced the piston down along with the end of the beam that was connected to the piston. The other end of the beam, which acted as a pump handle, was suspended and a pump bucket raised water.
There were several truly ingenious innovations in Newcomen’s design:
- The idea of condensing steam by spraying water inside the cylinder.
- The method of making the piston air and watertight inside the cylinder. At the time it was impossible to make the cylinder perfectly cylindrical, so the piston could not fit tightly inside the cylinder. Without an airtight fit, the vacuum could not be created in the cylinder. To solve this problem, Newcomen attached a leather flap around the edges of the cylinder and filled it up with water. The weight of the water would seal the leather. This was a clever solution!
- “Snifting valve” to drive any air that accumulated in the cylinder during condensation.
- Finally, Newcomen automated the openings and closings of the valve that controlled access of water into the cylinder for condensation. Take a look at “Plug frame’ in the image below. This long pole was attached to the beam and two tappets T1 and T2, which would close and open the valve W when the piston went down or up the cylinder. The method completely automated Newcomen’s engine; without this method, a person would have had to stand next to the engine opening and closing the valve during each cycle.
The Newcomen's Engine
The point that I would like to stress is that one of the fundamental differences between Newcomen’s engine and Papin’s apparatus was in the separation of the boiler. Papin’s contraption had the boiler inside the cylinder; Newcomen put the boiler to generate steam in a separate container.
Once again let’s skip a few years forward and look at Watt’s Engine.
In 1765, James Watt invented the most important innovation in the history of the steam engine. The Newcomen’s engine required heating up the cylinder to boiling temperature and then cooling it down to room temperature each stroke. This was inefficient and wasted a lot of steam. If Watt wanted to create a more efficient engine he had to solve the following contradiction:
The engine cylinder must be kept hot all the time in order to maximize efficiency and the cylinder must be cooled down once per cycle to maximize power.
Watt’s genius solution was in separating the condenser and the cylinder. This would allow the condensation of steam in a separate container while keeping the main cylinder hot. This innovation contributed a savings of almost 75% in fuel!
Watt's Engine - Separate Condenser
Just like Newcomen separated Papin’s unit that contained the boiler inside the cylinder into two independent parts, the boiler and the cylinder, Watt separated Newcomen’s unit that contained the condenser inside the cylinder into two independent parts, the cylinder and the condenser. It was exactly the same principle of separation!
The image below clearly shows this process.
The Principle of Separation & The Evolution of steam engine
This principle of separation is not unique to the steam engine industry only; it could be applied to solving different problems in different industries. Understanding it might help you solve your own problems. In one of my future posts I will write up a few examples of innovations from various domains that were invented by applying the principle of separation.
_________________
References
Dickinson, Henry. A Short History of the Steam Engine. London: Cambridge University Press, 1939
Cardwell, D.S.L. From Watt to Clausius. Ithaca, NY.: Cornell University Press, 1971
Pacey, Arnold. The Amazing Ingenuity. Cambridge, MA.: MIT Press, 1992
Reinventing the Same Things Over and Over
Applying for a patent is a time and money consuming process. It might cost $10,000+ and takes years of waiting and negotiation. Even if you do get a patent the odds of making any money off of it are very slim. I remember reading somewhere that less than 2% of all patents end up make money. However, this does not seem to deter people from applying for patents for truly novel devices but also for, what seems to me, devices that have been invented and patented a long time ago.
Following are two relatively new patent applications for swimming training devices that appear to me to be re-inventions of the same old wheel. It’s a shame, in my opinion, that so much time and energy by obviously creative people is spent on these types of inventions, neither incremental improvement nor true innovation.
The first example is a 2010 patent application for a “Device and method for swimming in-place”:
A device and method for allowing a swimmer to swim in place comprising using a device with a swimmer attachment element adapted to fit over a part of the swimmers body, an anchor attachment element connected to the swimmer attachment element and adapted to attach to an anchor, said anchor configured to immovably absorb the forward thrust of a swimmer.”
Here is the patent that was issued in 1994 for “Stationary swimming apparatus”:
A device for pool use that holds a swimmer stationary. A base strap attaches to a stationary poolside object… The swimmer can then engage in continuous swimming exercise in a small pool as the stationary swimming apparatus holds the swimmer stationary with respect to the poolside object.
Both of these devices describe the same thing in two different ways. If you search the patent office web site, you will find several more patent applications for similar devices.
The second example is another 2010 patent application for a more complicated device “Swimmer training device”:
A swimmer training device includes a frame, a variable weight device, a first block, a second block, and a cable.
One embodiment of this invention describes a container that could be filled with water to be used as variable weight. Compare this device to the patent application that had the same title and was patented in 1973 “Swimmer training device”:
The present disclosure is directed to an apparatus having variable weights which may be attached to a line connected to a belt worn about the waist of a swimmer for applying weight to provide a restraining force against a swimmer attempting to swim away from the device which helps build, condition and tone the various muscles of the human body employed in swimming.
Again, the same device is described in two different ways. Swimmers know this bulky and expensive device as a power tower.
I should add that even though I think that these two patent applications are filed for devices that have been invented a long time ago, it doesn’t mean they won’t be patented. If a patent examiner finds that there is something novel in these implementations, the patent might be granted. However, that will not change the fact that the swimming cord is just a swimmer cord and a power tower is a power tower, regardless of what you use for variable weight.
