and if you want to show a battery you make as many pairs of parallel lines as there are cells in this fashion:
And just so with every separate piece of electrical apparatus, and all of them are shown at A and B in Fig. 31.
How to Read Electrical Diagrams.—From the plates of symbols given at A and B in Fig. 31, you will see that the symbol for a battery is a pair of parallel lines as shown above, that the symbol for a motor is made in this fashion:
and that a switch is made like this:
now if you want to show a battery, a motor and a switch wired together all you have to do is to join the symbols with lines as shown at C in Fig. 31 and you will have what is called a diagram.
You can read a diagram, that is understand how it is connected up, in an instant for you can see at a glance how the wires run. Because the wiring is shown so simply and clearly diagrams of this kind are usually called wiring diagrams.
In drawing wiring diagrams try to place each symbol in such a position that the connecting lines which represent the wires cross each other as seldom as possible, otherwise your diagram will be confused and it will be hard to follow out the circuits.
Some Aids to Drawing.—The following aid to drawing and designing was published in the English Mechanic and you will find it very helpful if your invention has to do with an automobile, aeroplane, or any large machine which is used or actuated by a person.
Make a manikin, that is a little jointed figure of a man as shown at A in Fig. 32. The figure can be made to any scale but 1 inch to the foot which is ⅙ full size is a good ratio to make it but it must of course be made to the same scale as the machine you are drawing.
To get the right proportions rule a sheet of paper a couple of inches wide and about 8 inches long so that the divisions will be ¹/₁₂ inch square and draw on this the different parts of the manikin as shown at B in Fig. 32. Now since every ¹/₁₂ inch on the paper is equal to 1 inch for a man 6 feet tall your manikin will be 6 inches high when it is jointed and complete.
The figure can be made of cardboard if it is to be used only a few times but thin wood, celluloid or hard rubber, or sheet tin, brass or copper will make a much more substantial one. Whatever the material that is used the edges of each part should be filed smooth; and when you rivet the parts together to make the joints the latter should work smooth and yet stiff enough so that the parts will stay in whatever position you place them.
When you lay the manikin on your drawing you can see whether or not the levers are in the right places as shown at C and D in Fig. 32.
Making Cardboard Models.—In drawing out your invention you will often find that you can’t get the image you have in your mind’s eye down on paper.
There may be the movement of a lever, the turning of a wheel or the motion of a cam that you cannot quite see through and try as you will to work it out on paper the thing refuses to materialize. Under such conditions it would be a great waste of time and money to set about building a real model but there is an easy way out of the difficulty and that is to make a cardboard model of the device.
Just as an illustration take the case of an aeroplane. Say that your big idea is a scheme for controlling the elevating planes and the direction rudder; you have clearly in mind the use of an elevating plane on each side of the rudder and yet when you try to draw it out these two parts won’t fit together at all as you expected them to do.
When you reach this point get a sheet of heavy cardboard, shears, bottle of liquid glue, pins, matches or toothpicks, some thin wire, a few corks and a sharp knife.
Out of these materials you can build up the fuselage, as the body of the aeroplane is called; next you can fasten on the rudder and then the elevation planes; and when you have the tail-planes put together with real materials and actual shapes and sizes they will stand out in bold relief and you will have no trouble in making your drawings from the cardboard model.
Or suppose you have an idea for a gyro-motor such as are used for driving aeroplanes. Now in this motor the shaft to which the pistons are fastened stands still and the cylinders in which the pistons move revolve. It is rather a curious motion and not easy for a fellow who is not posted on mechanics to grasp offhand.
What’s the thing to do? Why, make a cardboard model of the mechanism using pins for the shafts and you will have a model that will look like Fig. 33, and when you turn the cardboard disk with the cylinders marked on it you will see at once exactly how the motor works.
And so it is with many other contrivances; when you come to any part that doesn’t seem to fit or is not clear, make a cardboard model and your troubles will vanish as dew-drops in the morning’s sun.
CHAPTER III
THE STATE OF THE ART
Taking it for granted, now, that you have drawn out your invention on paper and have made cardboard models of the more difficult parts so that you can see about what your device or machine will look like and how it will work your next move is to look up the state of the art.
What is Meant by State of the Art.—The state of the art means everything that has been published either in books, papers, or in patents about anything that has been discovered or invented, which has a bearing on your invention.
As an instance the state of the art of the dynamo electric machine, or dynamo as it is called for short, goes clear back to 1833 when Faraday made the experiment of passing a wire across the pole of a magnet and found that a current of electricity was set up in it—that is in the wire. Since that time hundreds of patents have been taken out and thousands of articles have been written about dynamos.
All of this information, or data as it is called, goes to make up the state of the art in the class of dynamos and all of the patents can be had and many of the articles too if you know how to go about it to find them and one of the purposes of this chapter is to tell you how to do it.
Use of the State of the Art.—You can easily understand that with all the thought that has been given to, and the experimental work that has been put on, dynamos to the end of bettering them it is a pretty hard thing to make an improvement that has not been made before, though it is still quite possible to do so.
Suppose, then, you had thought of and worked out on paper some improvement on the dynamo which you believed to be new and original and of great value. Certainly since you know that inventors like Edison, Brush, Weston, Thompson, Tesla, and a hundred other men almost as big, had applied themselves with diligence to dynamo problems during the last 40 years you would not care to go very far in spending your time or your money working on it until you learned whether or not some one before you had thought of and used the same principle.
Yet hundreds of beginners in the field of inventing work along in the dark because they do not know the state of the art, and always to their sorrow. So don’t be one of them.
How to Learn the State of the Art.—For the reasons I have given above you will see that it is bad practice to go beyond the point of working out your invention on paper before you know whether it is really new or not for though it may be entirely original with you, if it has been thought of and read before some learned body of scientists, or printed in some musty trade paper prior to the time you conceived the idea you haven’t the slightest claim to it, nor is it of the least value to you.
And so after you have thought out your invention and have made drawings of it the next step is not to apply for a patent as most patent attorneys will advise to do, or to have a model made as many model makers will tell you to do but to look up the state of the art and see where you are at.
Having a Patent Attorney Look it Up.—The easiest and quickest way to learn roughly the state of the art is to have a preliminary search, as it is called, made by a patent attorney, which means that he will look through the files of patents that have been granted by the United States Patent Office to other inventors for devices or machines of the kind you are working on.
To do this you must, of course, retain a patent attorney, that is employ him, and turn the drawings and written description of your invention over to him. Every patent attorney outside of Washington, where the patent office is located, has a correspondent or an associate, that is another patent attorney, who lives there and who acts for him when necessary.
This latter patent attorney will take your drawings and description to the library of the patent office, look over the files of patents there and pick out those which seem to him are most nearly like your invention.
He will get copies of these patents, send them to your patent attorney who will in turn hand them to you with your original drawings and you can then go over them and compare them and judge for yourself whether you have a really new invention or if it burned in the brain of some other inventor before you ever dreamed of it.
From the above you might infer that it would be a good scheme to employ a patent attorney who lives in Washington; but on the contrary it is better to have a patent attorney in your own city transact this business for you, if one is to be had, for then you can talk with him and you will learn many things you couldn’t begin to find out through correspondence.
Many advertising patent attorneys agree to make what they are pleased to call a free search for you—and do it while you wait, so to speak. A free search, or desk search, as it is dubbed by those who don’t make them, is of no value whatever for it is the snap-shot opinion, or rather a notion, of a patent attorney who is drumming up business by un-business like methods.
To show how absurd an opinion of this kind is just consider that there are 43 divisions of inventions in the patent office; each division, is split up into anywhere from a dozen to nearly 200 classes and that in some of these classes as many as 12,000 patents have been granted as in the case of the sewing machine.
And when you ask a patent attorney of this ilk to make a free search for you he will write back a letter in this tone of voice: I have very carefully considered your sketch, etc., etc. The first payment of fees necessary to start your case is $20 and upon receipt of this amount I will be very glad to carry the case forward, etc., etc.
All patent attorneys who advertise that they will make a search for you free of charge will also make what they call a special search for which they charge $5.00, and any other patent attorney will make one for the same price and which is, after all is said and done, only a preliminary search.
You can buy a copy of any patent that has been issued by sending 5 cents in coin—the government won’t take its own stamps—to the Commissioner of Patents, Washington, D. C., that is if you know the number and date of it and the name of the inventor to whom it was granted. The patent attorney who makes the preliminary search will send you several copies of the patents nearest like your drawing without extra charge as these are, or should be, included in your $5.00 fee.
When you get the copies of these patents go over each one carefully and see how nearly the pictures are like yours; then read the description of the invention, or specification as it is called, and compare it with your own statement, and, finally study the claims at the end of the specification and pick them to pieces for in these are to be found what has really been allowed to the inventor by the patent office.
The patents found by the patent attorney in making a preliminary search of the files and which are sent to you does not by any means represent the whole state of the art, but they serve a useful purpose as a starter. The reason it is not complete is because the patents are usually selected by patent attorneys in virtue of their similarity to the drawings you have submitted to him. Sometimes, to be sure, he reads what the specification says and if he is a real good patent attorney he will sift out a few of the claims, though this is usually due to his patent training rather than to any conscientious desire on his part to get at all the facts in the case.
But when you have applied for a patent on your alleged new and useful improvement and it is being scrutinized by the examiner in the patent office, he will look up the state of the art in all its devious ramifications for this is what he is paid to do by the people of the United States, though he thinks it is the officials in Washington who employ him. At any rate he has plenty of time to do it in and ample assistance to do it with.
Nor does he merely take a glance at the drawings, specifications and claims of your patent application and compare them casually with others that have been granted along the same line of endeavor, but, instead, when enough pressure is brought to bear, he will look up everything that has ever been published in all languages, including the barbaric ro,[1] since Adam was a boy.
At other times and for no reason at all, or so it seems, he will of a verity go to sleep on the job in his sub-cellar and let an application slip through his room in a few months, while he will spend years on another application of the same kind. Of course if you are the fortunate one you will be glad to get a patent granted so easily; your patent attorney is glad because he has your money in his pocket and the examiner is glad because he has made a friend of his glad.
To have everybody glad is a nice thing, you will allow, but don’t crow too soon for there is a hole in the average patent big enough to drive a horse and wagon through. If your patent is for an invention of genuine merit you will not be alone very long in the field and should you commence to make anything that looks like real money out of it you will find some other genius with an invention and a patent, as like yours as the other Siamese twin and if you don’t sue him he will sue you and then you can fight it out in the courts.
Even as right is always on the side of the army with the heaviest artillery, if there are enough shells, so, too, justice is always on the side of the inventor who has the smoothest patent attorney and the cleverest experts if they have enough ammunition in the way of some claims. While it requires skill to draw up good claims they can in any case be made better where the state of the art is known by yourself and your patent attorney.
How to Look It Up Yourself.—Whatever the nature of the invention you are working on you should read up its history from its earliest beginnings and in this age of papers, books and public libraries this is an easy, entertaining and profitable thing to do.
As an illustration take the art of flying and let’s suppose you are working on a new wing, or main-plane, for an aëroplane; if you will go over the list of books sold by book publishers, or consult the catalogue of a public library you will find books on flying, or aviation as it is called, that will give you a full account of the development of flying machines; and if you will get the right book it will picture and describe all the forms of wings that have been invented and patented up to the time the book went to press. Then there are weekly and monthly papers published which are devoted entirely to the theory and practice of flying and by reading these you will be able to keep right up to the entering edge of the art.
Now what I have said about flying is just as true of whatever else you may happen to be working on, for books and papers are printed and published about nearly every subject you can think of, from aviation to wireless telegraphy; by reading up on the subject of and allied to your invention you will soon have the history of it by heart and this makes up a large part of the state of the art.
Another and fortunate thing when you look up the state of the art a lot of other ideas will surge helter-skelter through your mind and if you are careful to write them down many of them will be of much value to you in the furtherance of your invention.
If you live in a large city it is an easy matter to look up the patents that have been granted for inventions in your class, for you will find an Index of the Patent Office in the public library which gives the number and date of the patent you want and the patentee’s name. The Index is published every year by the Unites States patent office and it gives the alphabetical list of the patentees and of the inventors to whom patents were granted for that year.
Fig. 35. PATENT SPECIFICATIONS
Fig. 36. INDEX TO PATENTS
Having found the patent you want to look into, get the Official Gazette of the patent office for the same year and by looking up the number, or patentee, or invention, or all of them, you can easily locate an excerpt of the patent and then you can take a look at the drawing and read the principal claims.
The Official Gazette is published every week by the patent office and it contains a picture and a brief description of each patent issued for that week, together with the number and date of the patent, the name of the patentee and of the invention.
Should you require more information about a patent than is given in the Gazette you can look up a copy of the patent, or full specification as it is called, and these are bound in handsome volumes of 100 patents each, or at least, this is the practice of the New York Public Library.
In every library that has a patent section, that is a part devoted to patents, there is a librarian in charge who will either find any patent you want or who will show you how to use the Index, Official Gazette and the volumes of the full specifications.
The patent attorneys in Washington have things much easier as all of the patents are bound in books according to the class they are in and they only need to look over the volumes of a given class to choose those they want.
When you have learned everything you can from books, papers and copies of patents already granted about the subject you are interested in you will have a pretty clear idea of the state of the art and whether you are working in a virgin field or one that has been sown with the same kind of inventions by others.
But there is another and most important part of the state of the art which neither you nor your patent attorneys can find out about until after you have filed your application for a patent; this is the information contained in the applications for patents by other inventors before your application was filed.
Should another application disclose either in whole or in part an invention like, or nearly like, yours, or rather that your invention is like, or nearly like, some one’s else, the patent examiner declares what is called an interference, of which more will be said in another chapter, and this gives the patent attorneys on both sides another chance to rake in a few more fees.
What to Do When You Find There Are No Other Improvements Like Yours.—After you have looked up, or have had looked up, the state of the art as carefully as possible, and you are satisfied that your invention, or improvement, is different from everything else you have been able to find, you should by all means go ahead and make such experiments, or build a working model, as the case may be, in order that you may know that all you have thought about it is really true.
As soon as your experiments are completed or your model is finished so that you know exactly what you want to claim as being strictly new and novel and original with you, then you are in shape to hire a patent attorney to draw up your patent application and file it and don’t do the latter a moment before.
A patent application based largely on what you guess, is a patent when granted without value for it can no more cover the exact facts in the case when these are finally worked out than a description one might write about an imaginary trip to Europe would be likely to fit the true details of a real trip which he would make sometime thereafter.
When You Find There is a Resemblance.—Very often you will find after you have looked up the state of the art that some other inventor has patented a device that seems on the face of it quite like yours and yet when you examine them critically, compare them closely and bring thought to bear upon them you will be able to distinguish a difference and often in several respects.
Sometimes this difference, though it seems to be small, is a mighty one when it comes to producing results as for instance when Elias Howe used a needle with the eye near its point instead of in its head and so made the sewing machine a commercial success. And yet a patent examiner of to-day would not be likely to see any difference in a needle with an eye in its head and one with an eye near its point, that is, if he had never seen either one before.
If you have made a machine to do a certain thing and you find that another machine has been invented that does the same thing and in the same way you may be able to change the mechanical movements, or electrical devices, until you are able to get the same or a better result by other and better means. It is all very easy to tell you to do this but in practice it is often a mighty hard thing to accomplish.
The Bell telephone is an example of such difficulties, for while both transmitters and receivers can be made which work on principles quite different from those now in use the results are not nearly as good and hence the inventions have no practical value.
When Others Are Exactly Like Yours.—But when you find that your great idea has been thought of and worked out and patented by some other inventor ahead of you and that both the cause and effect which you and he arrived at are the same, then the best thing to do is to drop it like a hot potato and invent something else.
Note.—The Patent Office publishes a Manual of Classification, price $1, which lists all of the sub-divisions of each class. Take as an illustration Explosives, which is Class 53. This is subdivided into six such classes, namely: (1) Blasting Powder; (2) Fulminates; (3) Nitro Compounds; (4) Gun Powder; (5) Matches; (6) Pyrotechnic Compounds.
CHAPTER IV
HOW TO EXPERIMENT
The kind of experimenting you will do will, of course, depend altogether on the nature of the invention on which you are working.
But, as good fortune would have it if you are not mechanically inclined you are not apt to hit upon a mechanical invention. And if you know nothing of electricity, you are not likely to think out an improved electrical device.
But this much is certain if you are going to experiment the right way you must know something about the right way to experiment. No one should expect to work out to a successful conclusion a new machine or apply a new improvement to an old machine if he knows nothing of the first principles of mechanics or about mechanical movements, and by rights he ought to have some knowledge of machine design.
And the above statement is just as true of electrical inventions. A worker who does not know the difference between a binding post and an alternating current need not expect to progress very far with an invention of, say, an electric block signal system—unless he calls in an expert to help him; but what he should do is to study the principles of electricity and magnetism, learn the various currents that can be used and what apparatus and instruments are needed for utilizing these currents.
The same thing applies to inventions in chemistry in that to work intelligently you must know about the properties of substances, chemical change and acids, bases and salts. And with electro-chemistry both a knowledge of chemistry and electricity are needed.
It is easy to see that it would not be possible in the limited space I have here to say more than a word or two about the subjects of mechanics, electricity, chemistry and electro-chemistry when each requires a whole chapter to explain it even in a rough way and a whole book to explain it thoroughly. But there are a few things I can tell you about them that will put you on the right track and then I shall give you the names of some books that will be of great service to you when you are in need of them, and with your help we’ll make a real inventor of you.
How to Experiment with Machines.—Any one who possesses the slightest bent for mechanics can work out improvements on devices like egg-beaters and monkey-wrenches and feel their way as they go along.
But when it comes to designing and building real machines where numerous levers, gears, and springs are combined to make a working unit you should by all means read up on the subjects of work, energy and power, learn about the six mechanical powers—and the action of machines in general. The following definitions will give you an idea about all of them.
Work, Energy and Power.—A wheel will not turn of its own accord but if it is moved round by some force applied to it such as the hand, a coiled spring or a motor, work is done. In fact whenever a thing is made to change its position work is done.
The power to do work is caused by energy; energy is developed when some force is applied and can be stored up in bodies as when a ball is thrown. When the energy stops acting, or is used up, there can no longer be any work done. Energy can be transferred from one body to another, as from a clock-spring to a wheel, or from one wheel to another wheel; and energy can be transformed, as the chemical energy of a battery into the rotary energy of a motor or from steam into mechanical motion.
The unit of work is the foot-pound and this is the work done to raise one pound one foot high. The rate of doing work is the horse power and a horse power is equal to lifting 550 foot-pounds in a second, or 33,000 foot-pounds in a minute.
Energy may be either potential or kinetic; potential energy means energy that is stored up and with nothing to act on, and for this reason it is called energy of position. The electric charge of a Leyden jar is potential energy but the moment it is released it makes a spark and becomes kinetic energy or energy of motion. Potential energy can be changed into kinetic energy and kinetic energy back again into potential energy with amazing freedom. Energy has a definite relation to velocity which means that when the speed of a moving body is increased its power to do work is also increased.
Like matter, energy cannot be destroyed, and so all of it taken together is called a constant quantity. When the energy stored up in a spring, or a battery, has been used the energy is not destroyed, though it may be very hard to find out where it has gone, but you may know that it has vanished in heat and in other forms of energy.
Work Against Friction.—The chief resistance which machines have to overcome is caused by friction. Since there is no such thing as a perfectly smooth surface friction is always present in machines and much energy must be spent in overcoming it. The energy wasted by friction is not destroyed but is transformed into another kind of energy and that is heat. When a marble is rolled over the surface of a table there is less friction between the two than when the marble slides across the table. Hence with ball bearings there is less friction than with cone bearings. (See Appendix I.)
Forms of Energy.—There are nine forms of energy that you can make use of in your experiments and in your inventions, and these are:
Machines and the Principles of Machinery.—A machine is a contrivance of mechanical parts by which energy is transferred from one part to another. Beside the amount of energy required for doing useful work there must be an extra amount for overcoming the friction. Remember that no machine can either create energy or increase it, and, as you have seen, every machine wastes some energy in friction; this being true it must be clear then that it is impossible to make a machine which when once set in motion would continue to run forever, or at least until its parts were worn out. So don’t waste your energy in trying to invent a perpetual motion machine.
The Uses of Machines.—These are many and varied from a commercial point of view in that they are designed to do better, faster or cheaper work and sometimes all of these good qualities are found in a single machine.
From a mechanical point of view, though, a machine is used to
(1) Change one form of energy into another form, as steam into electricity.
(2) To make a slow moving, but powerful force produce a high speed or velocity, as in a sewing machine.
(3) To change a small, fast moving force into a powerful force, as in the action of a crowbar.
(4) To change the direction of a force so that the power can be applied where and when it is needed, and
(5) To make use of whatever force is at hand as the strength of animals, wind, water, steam, gas and electricity.
The Six Mechanical Powers.—As a matter of fact there are really only two of these, namely the lever and the inclined plane, the other four, that is the wheel and axle, the pulley, the wedge and the screw being simply modified forms of the first two.
The lever is a rigid bar resting on, and which can be moved about a fixed point, called the fulcrum. There are three classes of levers and these are:
(1) Where the fulcrum is placed between the load and the power which moves it, as shown at A, Fig. 37; a pair of shears, pliers, a balance and a crowbar are levers of the first-class, see B, Fig, 37.
(2) Where the load is applied between the power and the fulcrum, as shown at A, Fig. 38; a lemon squeezer and wire splicing clamps are examples of this class; see B, Fig. 38, and
(3) Where the power is applied between the load and the fulcrum as shown at A, Fig. 39; the foot treadle of a jig saw and sugar tongs are levers of this class. See B, Fig. 39. Then there is the bent lever, as shown in Fig. 40, where the power and load do not act parallel with each other, and the compound lever which takes the place of a single long lever as shown in Fig. 41, and which is used in large platform-scales.
The wheel and axle is really a form of lever and fulcrum. The axle provides a continuous fulcrum as shown in Fig. 42. Trains of wheel work, such as are used in clocks and other mechanical devices, are used to change a slow moving powerful force into a high speed, or velocity, or the other way about. Fig. 43 shows a train of wheel work.
The power is applied at A, the weight is at B, and the Fulcrum is at C.
The pulley is a wheel with a cord, rope or belt running round it as shown in Fig. 44. It is used to transmit power and also to change the direction of it. A pulley can be either fixed or movable. A compound pulley makes it possible to raise a heavy weight with a very small force, not by increasing the energy, but by transposing velocity into power.
Fig. 45b. ONE OF THE USES OF AN INCLINED PLANE
The inclined plane is any hard smooth surface set at a slant to the force to be overcome. A barrel can be rolled up an inclined plane against the force of gravity, as shown in Fig. 45, while it could not be lifted straight up to the same height.
The wedge is simply an inclined plane on a small scale. It is useful where a great force must be exerted through a small distance, as in splitting a stick of wood, as shown in Fig. 46.
Fig. 46b. TWO WEDGES FORM A PRINTER’S QUOIN
A screw is also a modified form of an inclined plane. By means of a screw great pressures can be exerted in a small space and here again a powerful force is had with a corresponding loss of velocity. It is shown in Fig. 47.
Fig. 47b. A SCREW CLAMP
Compound Machines.—Any of the above six simple machines can be combined with any or all of the others and every machine that has ever been invented for any purpose is made up of a combination of these six mechanical powers.
Since the beginning of invention there has been made by combining these six mechanical powers in different ways, a large number of simple machines called mechanical movements; and there has not been a single new mechanical movement invented in many years.
Hence when you begin to work on your machine don’t waste time and energy trying to devise the mechanical movement you need, or what is still more foolish attempting to invent a new mechanical movement but look at the pictures in Fig. 48 which gives over 60 of the most useful mechanical movements. If you cannot find one among them that will do the work then look for it in Gardner D. Hiscock’s book of Mechanical Movements which gives them all.
Books.—And it would be a good idea for you to read one of the following books which you can, most likely, get at any library:
- Elementary Physics: Elroy M. Avery.
- Elements of Physics: Edwin J. Houston.
- Elements of Physics: George H. Hoadley.
- College Physics: A. L. Kimball.
The first-named books go deeply enough into the subject of physics for all ordinary purposes while the last named is very thorough and has a lot of math in it; and all of them treat of liquids, air, electricity and magnetism, sound, heat and light. In whatever field you are working a general knowledge of physics will give you the key to a new and a mighty interesting world.