Answer to Question #186689 in Mechanical Engineering for Russ

Question

Produce three design proposals that will meet the requirements a classroom chair suitable for tall tables.The proposals should be presented as a small design portfolio which must include: sketches

 information about materials and bought-in components/sub-assemblies

 a brief overview of manufacturing requirements

 design calculations

 references to legislation, standards and environmental issues.

Answer 1

Anthropometric dimensions are considered as the foundation for designing ergonomically fit classroom furniture. Therefore, anthropometric measurements were taken according to the method of Pheasant and Haslegrave and which are shown in Figure below.

Seat Height (SH). It is perpendicular distance from the object’s sitting surface to the top of the head when sitting.

Shoulder Height (ShH). It is the vertical distance from the tip (acromion) of the shoulder to the sitting surface of the object.

Knee Height (KH). This is the perpendicular distance from the floor to the top of the right knee cap.

Elbow Height (EH). This is the perpendicular distance from sitting surface to the bottom of the elbow when sitting.

Buttock Knee Length (BKL). This is the horizontal distance from the back of the buttock to the front of the knee when sitting.

Buttock Popliteal Length (BPL). This is the horizontal distance from the back of the buttock to the back of the knee.

Elbow to Elbow Breadth/Elbow Width (EW). This is the horizontal distance across the lateral surfaces of the elbows.

Hip Breadth (HB). The hip breadth is the horizontal distance between the right side of the pelvic and the left side when sitting.

Thigh Clearance (TC). This is the vertical distance between the sitting surface of the object and the highest point on the top of the right thigh.

Popliteal Height (PH). This is the vertical distance from the posterior surface of the knee to the foot relaxing surface.

Forearm Fingertip Length (FFTL). The horizontal distance from the back of the elbow to the tip of the middle finger of the right hand.

Sitting Upper Hip Bone Height (SUHBH). This is the vertical distance from the foot relaxing surface to the upper hip bone.

Sitting Lowest Rib Bone Height (SLRBH). This is the vertical distance from the foot relaxing surface to the lower hip bone.

Eye Height (EH). This is the vertical distance from the foot resting surface to the inner canthus (corner) of the eye.

Stature (St). This is the vertical distance from the floor to the top of the head.

The most common type of classroom furniture (bench) utilized in primary schools of Bangladesh is shown below. These furniture items are made by nearby furniture manufacturers with the absence of standard ergonomic measurements. To identify the potential mismatches, the following measurements of the existing classroom furniture were measured.

Seat Height (SH). Seat height is measured as the perpendicular distance from the floor to the middle point of the front edge of the seat.

Seat Width (SW). Seat width is measured as the horizontal distance between the lateral edges of the seat.

Seat Depth (SD). This is the minimum distance measured horizontally from the front edge of the sitting surface to its back edge.

Seat to Desk Height (SDH). This is the vertical distance from the top of the front edge of the seat to the top of the front edge of the desk.

Seat to Desk Clearance (SDC). This is the vertical distance from the top of the front edge of the seat to the lowest point below the desk.

Desk Width (DW). Desk width is measured as the horizontal distance between the lateral edges of the desk.

Desk Depth (DD). Desk depth is the distance from the back to the front of the top surface of the desk.