Ratchet Mechanism

Ratchet Mechanism


a toothed mechanism for the conversion of reciprocating rotary motion into intermittent rotary motion in one direction.

As shown in Figure 1, a ratchet mechanism consists of a ratchet wheel (1), a driving pawl (2), an arm (3), a locking pawl (4), and a support (0). The driving pawl engages the teeth of the ratchet wheel under the action of a spring or of its own weight. When the arm moves counterclockwise, the driving pawl turns the ratchet wheel through a certain angle. When the arm moves clockwise, the catch slips past one or more teeth, but the locking pawl prevents the clockwise rotation of the ratchet wheel.

Figure 1. Diagram of a ratchet mechanism

Ratchet mechanisms are used in, for example, bicycles and machine tools. In load-lifting machines, ratchet mechanisms prevent the drum of the winch from moving backward under the weight of the load.

References in periodicals archive ?
Ministers face key sticking points including finance for poor countries to cope with climate change, a long-term goal to bring greenhouse gas emissions to zero and a review and ratchet mechanism allowing countries to revisit their climate action plans and increase ambition.
That is why countries are rightly seeking to build an upwards ratchet mechanism into the agreement.
Mounting Bolt And Nut Size M8 X 50Mm, Foot Rest Paddles Frame And Pedal Rod Should Be As Per Is 617-1994 Grade 4223A, Metal Of Ratchet Mechanism, Pins Etc.
The Kuhn Rikon Ratchet Grinder combines a high performance ratchet mechanism with a ceramic stone grinder, making it ideal for those who want more flavor fast.
Caption: Kuhn Rikon: Sporting a ratchet mechanism rather than a pump or ripcord, Kuhn Rikon's Ratchet salad spinner is ergonomically designed, comes with a handy brake to stop the spinning, and has a 16-cup capacity.
Despite being faulty - the ratchet mechanism was not working - numerous bidders in the room competed with four telephones and countless Internet bidders, taking the price skywards.
He had the answer and he gives it to me: "Because when a bird lands Picture by Paul Norris on a tree there's a ratchet mechanism which makes the foot grip automatically.
Reliability in retrieving the plug is provided via the plug's robust ratchet mechanism, combined with the element being positioned above the slips.
When this was turned, it worked a ratchet mechanism (you can see that I'm no engineer).
Combine that with a ratchet mechanism within the spanner head so you don't have to remove it and reposition the spanner and you have a tool that makes light work of the most awkward of jobs.
Maynard did not invent a "cap gun" per se, but rather a system utilizing a compartment, ratchet mechanism and a tape primer that could be fitted onto current muzzleloading rifles and pistols.
At a conference this morning he said, "The Goodwill Tractor Company did not originate that ratchet mechanism.