Lesson Notes By Weeks and Term - Senior Secondary 3
Locking devices
Locking devices
TERM – 1ST TERM
WEEK SIX
Class: Senior Secondary School 3
Age: 17 years
Duration: 40 minutes of 5 periods each
Date:
Subject: Technical Drawing
Topic: LOCKING DEVICES
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
I.) Discuss the concept, locking devices.
II.) Identify and discuss the types of locking devices
III.) Draw out the various types of locking devices identified.
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,
INSTRUCTIONAL PROCEDURES
PERIOD 1-2
|
PRESENTATION |
TEACHER’S ACTIVITY |
STUDENT’S ACTIVITY |
|
STEP 1 INTRODUCTION |
The teacher explains the concept, locking devices and discuss the types. |
Students listens attentively to the teacher |
|
STEP 2 EXPLANATION |
Teacher guide students to draw out the various types of locking devices identified. |
Students exhibit attentiveness and active engagement |
|
STEP 3 NOTE TAKING |
The teacher writes a summarized note on the board |
The students copy the note in their books |
NOTE
LOCKING DEVICES
Locking devices are mechanisms used to prevent relative motion between two parts of a machine or structure. They ensure that components stay securely fastened together, reducing the risk of loosening or separation due to vibrations, movement, or external forces.
Types of locking devices
1. Lock Nut: A nut designed with special features to resist loosening, such as nylon inserts, deformed threads, or serrations. These features increase friction between the nut and bolt, preventing unintentional loosening.
2. Washer: Washers are thin plates with a hole in the center, placed between a nut and a bolt or between a nut and the surface it's fastened against. They distribute the load evenly and can also serve as locking devices, especially when using split washers (spring washers) or toothed washers.
3. Slotted Nut: A nut with slots or grooves cut into its top surface. These slots accommodate a cotter pin or split pin, which is inserted through the nut and bolt to prevent loosening.
4. Keys: Keys are used to secure rotating machine elements like gears, pulleys, or couplings to a shaft. They fit into slots (keyways) machined into both the shaft and the component, preventing relative rotation.
5. Splines: Splines are ridges or teeth machined onto a shaft or within a bore. They match corresponding grooves or teeth on a mating part, transmitting torque while preventing relative motion.
6. Set Screws: These are threaded fasteners with no head and are tightened against a shaft or component to prevent movement. They often feature a pointed tip that digs into the surface to provide grip.
7. Thread-locking Adhesives: These adhesives are applied to threaded fasteners before assembly. They cure to form a strong bond that prevents loosening due to vibration or shock.
EVALUATION: 1. Sketch the figure below
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively