Where the hell are the patents?

Where the hell are the patents?

I’m working on a number of new articles for the patents section. It just takes so dreadfully long to do the research and pull them together. Well, not almost a year long. That’s a 50/50 combination of too busy and too lazy to do extracurricular work. I have a backlog of about 50 patents in my archives I’ve been sifting through, and these are the ones I’m focusing on:

1938 shoe fitting machine patent – complete with a dose of radiation

Patent for foot flouroscope - how about a dose of radiation with that shoe fit?Alexander Graham Bell’s 1902 patent for his aerial kite

Page from Alexander Graham Bell's 1902 aerial kite

An 1892 submarine patent

Page from an 1897 submarne patent

Fitted sheets – because who doesn’t like a patent for a torture device

Page from patent for fitted sheets

The Bell patent is going to take a lot more research, so it is an unlikely candidate. It may be the fitted sheets because the entire contraption is so over complicated and vicious looking, I can’t resist.  If you have a preference, drop a line in the comments section. I’ve had to layer on quite a bit of spam protection so you’ll have jump through a few spam prevention hoops, but I do enjoy hearing from people. If you have an idea for me to explore, I’d be thrilled to hear it.


The unmitigated terror of lawn darts – we have a patent for that!

The unmitigated terror of lawn darts – we have a patent for that!

Are you old enough to remember being terrified of being skewered by a lawn dart? You know, those metal pointed, weighted darts that look like miniature javelins with fins? In any other dimension, they’d be treated as a weapon, not a game for children. I’m periodically stuck on the subway with nothing to do but let my brain wander through a tangled landscape of ideas and half written articles and during a rather epic delay underground recently, I began thinking about lawn darts and wondered why I no longer saw them.

Photo of an old Hasbro Javelin Darts set

We had a neighbour, years ago, who owned a set, decades ago, and I hated them… the darts, not the neighbours. Their kids where a bit cavalier about launching them into the air and woe to anyone who got in their way. The metal tipped missiles created havoc when they went astray.  I looked for the original lawn dart patent from sometime in the 1950s, but had no luck. I managed to dig up an old Hasbro patent application from 1970 that reworked the design a bit.  Scan from 1970 Hasbro Lawn Dart Patent

The pointy bit was still made of a heavy metallic material (usually lead) so it would hit the ground with sufficient force and not wobble about. The new bit was a proposal to use molded plastic for the fins and shaft to cheapen the costs per unit.

“Referring now to the drawings, there is shown generally at 10 a dart construction comprising a weighted head portion 12, a metallic shaft 14 extending from one end thereof and terminating in point 16, an elongated plastic shaft 18 extending from the opposite end of head portion 12, and a tubular portion 20 having vanes 22 extending integrally there from.” 1

Irwin also manufactured a popular series. I couldn’t find the original patent, but did find one from 19762. It looks equally deadly: Drawing from Irwin Toy's lawn dart patent 1975

In hindsight, it should never have been a game marketed to kids. Then again, my neighbours shouldn’t have left the darts unattended, but that was the 60s – survival of the fleetest of foot.  The concept of lawn darts is a fun one … the delivery, not so much if you get nailed by one, which prompted me to see if anyone has come up with a solution to their deadliness. The trick, I suspect, is the darts have to have a number of features to be effective, including sufficient weight and a pointy end that sticks into the ground, which is what makes them such efficient weapons. Without a tip, proper weight distribution and fin length, you end up having a sad game of “toss the metal tube about and hope it eventually sticks into the ground”.

The metal tipped version was outright banned in Canada in 1989.  Why? According to tests, lawn darts could exert 23,000 pounds of pressure psi – enough to crack through a human skull and puncture the brain. Which it did. In less than a 10-year span, over 6,000 people made trips to the emergency room for treatment – 80% were under 15 years old and 50% under 10.  The injuries included “punctures, lacerations and fractures to the head and skull”3, along with eye injuries, usually to bystanders.

“The combined factors of weight, the narrow elongated shaft, the speed that the dart is traveling at the time of impact, and the thickness of the child’s skull at the point of impact present the risk.” Consumer Product Safety Commission3

In the US the darts were eventually banned, unbanned and then banned again [see articles below for the full, tragic story].  It’s a bit complicated. Currently, there is a brisk trade in used sets. Just scan Kijiji or Craig’s list in the summer and you’ll see people begging to find a set to buy. I spotted one person offering over $200 for a set.  I was a bit surprised by this, especially given their ability to maim. Nostalgia overrides safety sometimes.

As it turns out, a few people filed patents for safe lawn darts. Most didn’t make it off the drawing board. Many of the patents focused on using a blunt tip. It’s a decent idea, but the darts don’t always stick into the dirt, in as much as they plop to the ground and bounce about a bit. Given enough height, they will penetrate the ground, but then we’re back to the same issue – weight, height and skulls don’t mix. Others tried a combination of lighter non-metal darts with blunt tips or flat bottoms rather than tips. Again, people complained about lack of control when the darts were thrown. The thing about traditional lawn darts is they stayed where they dropped, making it easier to score.

Most modern versions of lawn darts have settled on a uniform design: Photo of Coleman's Lawn Dart sets - modern safety "darts"

Coleman’s is typical – blunt, flat bottomed, soft end to prevent skull damaged and weighted to help with stability. Poof makes a set that looks a bit more like a traditional lawn dart, and using the Jarts brand name, but with a round plastic ends rather than metal. Far safer, but many people complained they couldn’t stand up to a lot of impacts and fell apart.

photo of Poof companies safety Jarts

The biggest issue is the newer lawn darts bounce about too much making it hard to score. Most complaints appear to come from people who played the original lawn dart games and lament the lack of accuracy and control the old javelin styled darts had. Issues seem to revolve around whether the ground is too hard and dry or the grass is too long. Either cause serious bounceage (not a word, I know). I suppose you could hose down the backyard before playing but that brings a new set of problems to the game. Without the traditional javelin point, bounce will continue to be an issue. But seriously, it’s a backyard game not the Olympics.

I have an idea that might work. Get a large cloth made of Velcro, cut it into squares with numbers and scatter them around the yard. They need to be largish swaths of material or the game won’t work.  Then Velcro tip flat bottomed darts. The darts should come in varying weights for different types of throwers, like real darts. Space out the cloths and then when you throw, the darts stick. Miss the cloth? Oh it’s like falling off the dart board, no score.  I like Velcro – it can solve so many of life’s little problems.


Read more:






  1. Original Patent https://www.google.com/patents/US3672678?dq=inassignee:%22Hasbro+Industries,+Inc.%22&hl=en&sa=X&ved=0ahUKEwj04eSevKfVAhUi5YMKHchxCfw4ChDoAQh     kMAk
  2. Irwing Out Door Darts Patent https://patents.google.com/patent/US3982762A/en?q=lawn+dart&assignee=Irwin
  3. Consumer Product Safety Commission https://www.gpo.gov/fdsys/pkg/CFR-2015-title16-vol2/pdf/CFR-2015-title16-vol2-part1306.pdf
You knew I’d get around to litter boxes eventually

You knew I’d get around to litter boxes eventually

You just knew I was going to get around to litter boxes eventually, didn’t you? It was inevitable I’d start poking around patent archives to see what was out there. Colour me surprised – there are a LOT of patents for various cat litterbox designs. Everything from fully collapsible to pretty little houses for the fussy cat owner. It’s impressive how much brain power has gone into the basic concept of a litterbox.

After filtering through them, I settled on the earliest patent I could find. I present the 1939 Kramer self-flushing animal toilet, patent #US2204416A, filed 1939-04-13 granted 1940-06-11

Image from patent for the Kramer self flushing animal toilet

Sheridan H. Kramer, of St. Paul, Minn envisioned a litter box that attached to the building’s plumbing, was portable and could act as sleeping quarters for either a cat or small dog. Kramer had apartment dwellers in mind, hoping such a device would convince landlords to allow pets because the issue of sanitation would be addressed.

The design is interesting. The cat enters through a doorway into compartment A, which is designated as a sleeping area. Compartment B, the toilet tray, is accessed via a small opening from A. When the cat walks from B back to A, a small lever on the doorway floor is tripped by the cat’s weight and flushes the toilet.

Compartment B has a water tank that hooks into the apartment’s plumbing. The tray connects to the building’s sewage outtake for quick disposal. Figure 3 (image below) shows how the door lever is connected to the tank. The animal’s weight triggers the lever, which is attached to the tank handle. Water fills the tray and drains away through a series of holes under the tank (hard to see, but look for 26A in the image). The tray itself is on an incline so the water will flow towards the holes. When the cat steps off the door lever, the handle pops back into the up position and the water stops flowing. The tank will fill itself again and the tray will drain.

Image showing interior of Kramer animal toilet

If you look at figure 1, the one with the door, you’ll see a bunch of holes in the front panel. Those are air vents. The front door closes, in case you want to keep the cat or dog in one place.

On one level, it’s brilliant. No cleaning required. On another, not so practical. Installation would require permission from the landlord, which I doubt would be forthcoming. I tried to figure out a simple way of doing it, but nothing short of having a plumber come and refit a couple of pipes would work. It’s not like there’s are in/out pipes hanging around ready to be plugged into, especially at floor level. Not many landlords would be keen on this expense. Kramer did design this with portability in mind so you could hand fill the water tank, but that would quickly turn into a pain. And you’re still faced with flushing – where would water and feces go. As far as portability goes, this box would be heavy and not what I’d consider portable.

The other primary issue centres around the fact cats can be real assholes. Sure they like to crawl into small places, but have you ever tried forcing a cat to get into a small carrier? Battle armour and bazookas are the order of the day. Training a cat to use the tray could be a nightmare. Kramer admits in the patent, the animal may have to be locked into the box to force it to use the toilet tray. Some cats might train to use it, but most? Not a hope it’s going to happen.

Another issue comes to mind. Cats don’t like surprises. The flushing would send many cats into a frenzy to get away, especially if they are half way through the door and the water comes flooding in and soaks their paws. If you have the door shut, the cat would go into full panic mode and quite possibly never enter the box again. Think I’m exaggerating? Just cruise Youtube for videos of cats shocked by cucumbers on the floor (and please don’t do this to your cat, it’s cruel and rather stupid). They don’t do well with shock and awe tactics if they are the target.

If you manage to train your cat to use the box, you might find your water bill going through the roof. Imagine coming home to find out your furry friend decided to sleep on the door lever. Or they ignore compartment B and use A as their toilet.

Too many impracticalities likely killed the idea.


Inventions: Your Halloween Fright, and it’s not the jack-o’-lantern helmet that’s scary

Inventions: Your Halloween Fright, and it’s not the jack-o’-lantern helmet that’s scary

This one is interesting … and scary: “a new and useful Improvement in Jack-o’-Lantern Helmets”. I didn’t know there was such a thing as a jack-o’-lantern helmet, but we’ll assume it was a thing back in 1903 when this patent was granted. When I stumbled across this I first thought of a bike helmet. After looking over the patent, my second thought was “oh … oh dear. That’s a hell of a design flaw”.

Our inventor, one John Du Ket, of Toledo, Ohio, invented an easy to ship and assemble head mask for any occasion, “including campaign parades, masquerade balls and carnivals”. He was granted a patent Aug 25, 1903 (patent no, 737,371). After reading the patent, it becomes painfully aware why governments have health and safety regulations… and recalls.

If you give it a quick glance, it’s pretty cool. The key is the use of flexible cardboard that could be printed with whatever image the customer wanted. Say for instance a person wanted 100 Frankenstein heads for a parade, or 50 copies of the current presidential candidate’s head for a rally. No problem. They could be mass produced and shipped with little hassle. Du Ket’s design allowed the masks to lay out flat, ready for the person on the receiving end to assemble the kit, kind of like a Halloween Flatpack without the screw driver hassles. No assembly was required at the seller’s end, which would cut production time and costs.

Patent image from Jack o' lantern mask

In some ways, this is ingenious. He took a basic idea and added a modern marketing twist to it – fast to produce, easy to ship, offload assembly to the customer. What, you are asking, is so terrifying about this design? Let me show you:

Image from patent papers: Candle atop a person's head

“To secure the parts together in form for use, the sides 6 are first folded to form a socket, and a short piece of candle is inserted therein.”

Ponder that for a moment – a cardboard headdress, surrounding a candle in a metal holder that conducts heat, atop a person’s head.  One of his “improvements”, along with the use of flexible cardboard and a flat design, was the inclusion of a candle holder made of sheet metal.  Not sure what the weight would be like, but I’m quite sure after a short while it would be a bit much, especially when it heated up.

On the positive side, Du Ket did consider wax spillage:

Image from patent papers showing candle holder

“Preferably the diaphragm 2 is shaped by a die to form one or more grooves 16 concentric around the candle-socket, which are adapted to receive any of the material of the candle which may melt and run down on the diaphragm and prevent it spreading to the outer edges of the diaphragm.”

Grooves would be stamped into the metal candle holder and a spillage area would (hopefully) contain the wax. Just don’t move your head around a lot or risk it spilling over the lip of the holder.

Now if this doesn’t scare the crap our of you, you’re a stronger person than I.

Happy Halloween …


Read the full patent here  Jack-o’-lantern helmet.

Ponder the TV dinner cranberry sauce – yes, there is a patent for that.

Ponder the TV dinner cranberry sauce – yes, there is a patent for that.

Image from vintage Swanson's TV frozen dinner ad showing cranberriesEver lay in bed wondering about something and become obsessed with it? Over the past weekend, for reasons that admittedly mystify me, I became obsessed with the little cranberry slots in frozen tv dinners. You know that scoop of jellied red stuff that comes with frozen turkey dinners? It’s supposed to be cranberry sauce. What I began to wonder is, why doesn’t it turn into a pile of liquid goo when it’s heated in the oven? Why doesn’t it melt?  Guess what? There’s a patent for that, plus some mad cooking chemistry.

“Cranberry sauce is now so widely recognized as an almost indispensable accompaniment of any turkey dinner, that it is sorely missed when omitted from frozen turkey TV dinners.”
1964 Patent filing Ocean Spray

Ocean Spray was right, turkey dinners aren’t complete without cranberries. It’s big, big business. I can’t even envision Thanksgiving without a big dose of cranberry sauce. Adding a little tray of it to a tv dinner would be a strong selling point. Scoff at such an invention as cranberry sauce that maintains it’s form after being frozen & then heated, but it boils down to marketing dollars.

Of course, my first stop was a quick search of patents and there it was – the magic behind solidified cranberry sauce, courtesy of Ocean Spray, the cranberry behemoth in the US. They filed a patent for that tiny bit of red stuff in 1964 titled METHOD OF MAKING FROZEN DINNER CRANBERRY COMPONENT, United States Patent 73,360,385 granted 1969.

“A method for maintaining cranberry sauce in a gelled state upon thawing of a frozen TV dinner, comprising adding an acid tolerant, quick acting freeze surviving vegetable gelling agent such as hot hydrated starch to cooked cranberries, adding a sugar syrup, cooking the mix to form a sauce, placing an individual serving of the cooked sauce in the TV dinner package and subjecting the contents to a freezing environment to freeze said sauce.”
Patent filing Sept. 9, 1964, Ser. No. 395,323

Now, here’s the problem tv dinner makers faced with cranberry sauce – it wasn’t friendly to freezing.  It also wasn’t friendly to being made in large quantities. When manufacturers tried they were left with “packages … on thawing, in an ungelled flowing liquid so unfamiliar as to be unacceptable to the consumer” [r/f Patent]. Such a mess was unappetizing to the average consumer. So they were faced with the conundrum of how to make cranberry sauce on a large scale, have it freeze and bake while maintaining a shape and consistency acceptable to the public – but still be cost effective.

An interesting problem subsequently cropped up, even after a stabilized product was made – the mechanized process of dropping the sauce onto the tv tray broke down the gelled status, creating the same problem. Something in the mechanical pumping system caused the problem.  The option of having the cranberries scooped onto the tray by hand was discarded. It was far too time consuming and labour intensive to be profitable.

So that left them with the same problem – how to get cranberries onto the tray quickly and still have it recognisable.  The solution lay in cooking chemistry. After experimenting, Ocean spray came up with this mixture:

  • 500 pounds of cranberries
  • 30 pounds waxy corn starch to act as a gelling agent
  • 60 pounds of sugar syrup
  • 30 gallons of water.

The cranberries were cooked down in 25 gallons of water (at around 190F) and then strained.  The starch was mixed to the remaining water and heated to 190 F and then added to the cranberries. The syrup was immediately added and cooked until the mix reached an acceptable consistency. The sauce could then be piped directly onto the trays while hot and sent off to be quick frozen. When Ocean Spray popped the dinners into an oven, the cranberry sauce remained in a gelled state and didn’t “contaminate” the rest of the foods. And the rest is marketing history – turkey dinners complete with a little compartment of cranberries.

That’s interesting chemistry at work – you need just enough gelling agent and the right temperature to obtain optimal jelly status on an industrial scale. What’s not to love about that little blob of gelled cranberry sauce that is impervious to mechanical insertion, heat and freezing?

One thing that comes to mind is, has the recipe been altered now that that the dinners are on microwavable cardboard trays? Did they have to alter the recipe? Does microwaving effect the formula? Something to look consider.


Read the original patent here – Method for making frozen dinner cranberry component

Vintage ad for Swanson TV dinner with cranberries


“Drive like lightening” – building a better screwdriver

“Drive like lightening” – building a better screwdriver

How’s this for a piece of cool technology?  Image of a Robertson screw courtesy By User:Saforrest - Taken by User:Saforrest on 9 October 2007, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2888264

How many of us have cursed the traditional flathead screwdriver- usually that nanosecond you feel it slip in the groove and you know you’re about to suffer a disgustingly, ugly hand wound. Or cursed the Philips screw because the little star shape became damaged when the driver slipped.  There have been many attempts at improving the basic screw and my favourite is a Canadian invention – the Robertson:

Image of P. L. Robertson's patent illustration of Robertson Screw @1908

Why is this a perfect example of great tech at work? The design improves on an old idea – slip a screwdriver into the snug little square head and you can get an amazing amount of power behind it. Well, plus, for people like me who are a menace around power tools of all sorts, you never run the risk of the drill winging off creating embarrassing divots along the woodwork. There is a reason I don’t do home repairs.  But I’ll leave that for another tale.

Peter Lymburner Robertson is one of those underappreciated Canadian inventors who built a small empire a one small screw. Although many are familiar with the Photo of P. L. Robertson, inventor of Robertson screwsquare head screw (commonly refered to as a Robertson), few associate it with the man who invented it. That’s him over at the side. Robertson was living in Hamilton, Ontario and worked as a travelling salesman for a Philadelphia tool company.  He often related a tale of how  and why he invented the square screw. Robertson was demonstrating a spring loaded screwdriver in the summer of 1907 (the date varies between 1906 and 1907, depending on which source you look at) when it slipped and he received a bad slice on his hand. After that, he began designing a slip-less screwdriver. Withing a year, he had a satisfactory design and filed for a patent in Canada. By 1912, he held the patent internationally.

The simplicity in the design is awe inspiring:

This invention relates to screws, the heads of which have axial driving recesses or cavities instead of transverse slots punched therein and the invention consists in a recess or cavity extending into the screw head, the outer portion of the recess or cavity being prismatic and the inner portion thereof being pyramidal, the apex of the pyramid being in the axial line of the prism and of the screw. (from patent papers)

In short, the screw slot is square and punched deep into the screw head rather than a slot running the length of the screw. What makes this screw so much better than a slotted one?  Plop the screwdriver into the recessed square and it’s gripped tightly with nowhere really to slip off. You can start turning with no fear of it popping out. As well, the grip is so solid, you can put a lot of force behind each turn of the screw. The square shape also makes for a much hardier screw and more difficult to strip. As well, because the screwdriver fits so snugly into the square head, it’s possible to drill the screw with one hand, adding to it’s overall utility. 

Ad for the Robertson Screw

This was an important innovation, especially with industries looking to save time and money – a screw that could be inserted faster saved big dollars. It’s a bit hard to believe, but consider this, fewer slips of the screwdriver meant less damage to the item being manufactured. A win, win situation. After WW1, the Ford Motor Co initially used the Robertson on it’s Model T and A cars. By using the Robertson, Ford said his company could save an average 2 hrs assembly time on each vehicle. This presented a massive advantage in both savings and getting cars to market faster. The deal to use the Robertson fell apart when Ford wanted P.L. Robertson to sign an agreement that would allow Ford to make and hold all distribution rights for the huge US market. Robertson was adverse to siging a deal that potentially meant he would lose control over his invention.  Robertson refused to turn any rights over and unfortunately, when no monopoly was forthcoming, Ford switched over to the Philips screw. Philips was more than happy to hand over the rights.  In an odd twist of fate, this failed deal meant the Robertson never really took hold in the US, but it’s ubiquitous here in Canada. I doubt there are many tool boxes that don’t have a few Robertson screw drivers rolling around inside. 

Read more:
Archives Canada – Robertson Screw and Screwdriver
You can download the patent here: https://patents.google.com/patent/US975285A/en?q=screw,roberston&inventor=Peter+Robertson&before=19100101
Robertson Fastener website has a bit of info as well