The End
Activity 2.2.1 Observing Mechanisms
Introduction
A mechanism is a device that transmits movements so that the output movement is different than the input movement. It can be used to change the direction, speed, force, or type of movement. The output of a robot or any machine is motion and force in some form. A drill press, for example, has two kinds of motion: rotary and linear. The drill spinning provides the rotary motion; moving the drill down through the material is the linear motion. The force or torque applied to the drill must be sufficient to turn the drill through the material. Also, the speed of the drill bit must be within a given range. If the drill is turning too fast, the drill bit will be damaged. To acquire the correct speed, the drill press must have a pulley or gear system. Changing pulleys changes the speed of the drill bit.
When you are riding a multi-speed bicycle up a steep hill, what do you do? Most likely you shift gears in order to get more power with the same amount of effort. Sometimes when a standard shift or four-wheel drive vehicle is being driven up a steep incline, the driver will downshift or engage the four-wheel drive in order to gain more torque. Can you think of other examples where force or torque is changed to make a task easier?
This need to change speed and torque is a problem common to machine tools, robots, automobiles, and airplanes. In this activity we will study several techniques developed over the centuries to accomplish this task.
Equipment
Gateway notebook
Pencil
Procedure
1 Gears turn in a circular direction. There is an inverse relationship between torque and speed in gearing. A ten-speed bicycle has ten different gear selections. When you pedal up a hill, you use a gear train that provides more torque (turning force) but, in doing so, less speed.
When you pedal on flat land, you use a gear train that provides more speed, but in doing so, less torque within the gear
Introduction
A mechanism is a device that transmits movements so that the output movement is different than the input movement. It can be used to change the direction, speed, force, or type of movement. The output of a robot or any machine is motion and force in some form. A drill press, for example, has two kinds of motion: rotary and linear. The drill spinning provides the rotary motion; moving the drill down through the material is the linear motion. The force or torque applied to the drill must be sufficient to turn the drill through the material. Also, the speed of the drill bit must be within a given range. If the drill is turning too fast, the drill bit will be damaged. To acquire the correct speed, the drill press must have a pulley or gear system. Changing pulleys changes the speed of the drill bit.
When you are riding a multi-speed bicycle up a steep hill, what do you do? Most likely you shift gears in order to get more power with the same amount of effort. Sometimes when a standard shift or four-wheel drive vehicle is being driven up a steep incline, the driver will downshift or engage the four-wheel drive in order to gain more torque. Can you think of other examples where force or torque is changed to make a task easier?
This need to change speed and torque is a problem common to machine tools, robots, automobiles, and airplanes. In this activity we will study several techniques developed over the centuries to accomplish this task.
Equipment
Gateway notebook
Pencil
Procedure
1 Gears turn in a circular direction. There is an inverse relationship between torque and speed in gearing. A ten-speed bicycle has ten different gear selections. When you pedal up a hill, you use a gear train that provides more torque (turning force) but, in doing so, less speed.
When you pedal on flat land, you use a gear train that provides more speed, but in doing so, less torque within the gear