8

Passenger vehicles require suspensions for ride comfort. Most today use helical springs, but leaf springs were at one time a major advance over chain or leather strap suspensions, and are still used in some applications today.

Metal springs for vehicles predate the Bessemer process. Making a leaf spring starts with forging a thin, curved piece of metal. Making a superior one calls for a smart cooling schedules (e.g. initial quench, then slow cooling) and a careful choice of materials.

When did they appear in the historical record?

3

Leaf spring was first adapted to the horse drawn carriage in the 14th or 15th century. It didn't see widespread use until it's production became more practical in the 18th century. It cannot be said when "every" modern smithy was capable of producing Leaf Spring as each had it's own specialization as it were. I highly doubt you could walk into any smithy and ask for leaf spring at any point in history. You would have to visit what's called a "wheelwright" in the US. The only items I can safely say would be made in all smithy's are the common place and easily produced, IE nails, horse shoes.

  • 1
    Leaf springs are made from spring steel which was not mass produced until the mid 1800's (Bessemer process). Tempering and hardening the springs would have been within the skill set of most any blacksmith but the raw material was not. – Matt Balent Mar 31 '17 at 17:13
  • 2
    @AaronBrick: It will work just fine - until it breaks. That latter will occur rather quickly if the material has not been properly tempered. – Pieter Geerkens Apr 1 '17 at 12:10
  • 4
    Can you show a documented source for your claim of 14th or 15th century? – justCal Apr 1 '17 at 20:05
  • 1
    tractors.wikia.com/wiki/Carriage claims steel springs were introduced in the 17th century. In the 15th century the height of luxury was the 'chariot branlant', in which the carriage was suspended by chains (or possible leather straps) to form a crude suspension. It's not exactly a scholarly reference, but it reads well. – pokep Apr 30 '17 at 17:46
  • 4
    This answer would benefit from sources. – Mark C. Wallace Apr 30 '17 at 21:35
3

To answer the question in the title, apparently the leaf spring was invented in 1804 by Obadiah Elliott, a carriage builder in London, who was granted a patent for his leaf-spring-suspension vehicle on 11 May 1805.

The following extract from Leaf springs, their characteristics and methods of specification; a hand-book of useful information relating to automobile leaf springs, their manufacture, methods of specification, details and characteristics has a little more detail.

Obadiah Elliott, a noted English carriage builder of Lambeth, obtained a patent in 1804 for a means of suspending vehicles on elliptic springs. The Society of Arts awarded him their gold medal and the popularity of his product, and his success in general, were doubtless prompted by this official recognition of merit.

  • 2
    Elliot was granted a patent for an elliptical spring, which allowed the carriage to be built with a lower center of gravity. It is not the first leaf spring on a carriage, it's the design that made it popular. – pokep Jun 1 '17 at 16:40
1

Making a leaf spring starts with ...

A leaf spring is a spring with many leaves (or laminae) bound together. Typically made of steel (but in principle other materials could have been used, e.g. laminated wood)


When did they appear in the historical record?

According to The Steel Spring Suspensions of Horse Drawn Carriages (circa 1760 to 1900) by Gordon S Candle B.Sc., Ph.D., M.Sc., C.Eng, M.I.Mech.E. 1978:

Although there had been earlier instances of their use, it was only from about 1770 that the inclusion of laminated steel springs began to be regarded as normal practise.

  • This answer seems to be about multi-leaf springs, but I believe that single leaves came first. The citation is a good find and I'm hoping my library can find me the whole article. – Aaron Brick Sep 6 '18 at 16:46
0

Steel was commercially produced before the Bessemer converter by a "puddle" process. Replacing the puddle workers with the Bessemer process lead to the Homestead (Pinkerton) riot.

Good spring steel is more than low carbon. It also requires alloying with larger metal constituents to pin the metal polycrystals in place.

  • Sources would improve this answer. – Mark C. Wallace May 30 '17 at 23:12
  • The question was "when did leaf springs appear in vehicles" An answer needs a date, some description of what happened on & around that date and some good references. What led up to the Homestead riot and the composition of spring steel are not the question asked and are, at best, of secondary interest. – RedGrittyBrick Sep 6 '18 at 10:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.