Pins keys axial retaining rings Flra Hajdu B

Pins, keys, axial retaining rings Flóra Hajdu B 406 hajdfl@sze. hu

Content • Keys • Pins • Axial retaining rings 2020. 12. 08. Hajdu Flóra

Fasteners • scan 2020. 12. 08. Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design Hajdu Flóra

Keys • A key is a piece of steel lying partly in a groove in the shaft (keyseat) and extending into another groove in the hub (keyway). • used to secure gears, pulleys, cranks, handles, and similar machine parts to shafts, so that the motion of the part is transmitted to the shaft, or the motion of the shaft to the part, without slippage. • may act as a safety capacity; its size can be calculated so that when overloading takes place, the key will shear or break before the part or shaft breaks or deforms. 2020. 12. 08. Hajdu Flóra

Keys Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design • Types • Square and flat keys: widely used in all sorts of mechanical devices • square-tapered or flat-tapered keys: 1: 100 taper on their top surfaces • gib-head key: the same as the square - or flat-tapered key but has a head added for easy removal. • Pratt and Whitney key (parallel key): rectangular with rounded ends • Woodruff key: semicircular and fits into a semicircular keyseat in the shaft and a rectangular keyway in the hub. 2020. 12. 08. Hajdu Flóra scan

Tapered keys • Fastening by force • No axial fastening required • Small eccentricity is allowed 2020. 12. 08. Hajdu Flóra

Tapered keys 2020. 12. 08. Hajdu Flóra

Tapered keys - tolerances 2020. 12. 08. Hajdu Flóra

Tapered keys - assembly 2020. 12. 08. Hajdu Flóra

Parallel Keys • Fastening by shape locking • No excentricity • Axial fastening required 2020. 12. 08. Hajdu Flóra

Keys 2020. 12. 08. Hajdu Flóra

Keys – dimensions, tolerances 2020. 12. 08. Hajdu Flóra

Shaft with keyseat – parallel key 2020. 12. 08. Hajdu Flóra

Shaft with key - construction 2020. 12. 08. Hajdu Flóra

Shaft with keyseat – Woodruff key • Transmit smaller torque • To prevent tangential displacement of plates mounted on tapered shaft ends 2020. 12. 08. Hajdu Flóra

Shaft with Woodruff key - construction 2020. 12. 08. Hajdu Flóra

Shaft with feather key Source: Szabó László: Oldható kötések alkalmazása, szerszámai, technológiája The part must be axially movable 2020. 12. 08. Hajdu Flóra

Splines • A splined shaft is a shaft having multiple grooves, or keyseats, cut around its circumference for a portion of its length, in order that a sliding engagement may be made with corresponding internal grooves of a mating part. • carry heavier loads than keys, • permit lateral movement of a part, parallel to the axis of the shaft, while maintaining positive rotation, and allow the attached part to be indexed or changed to another angular position. 2020. 12. 08. Hajdu Flóra

Pin fasteners • Pin fasteners are an inexpensive and effective method of assembly when loading is primarily in shear. • 2 groups: • Semipermanent • Quick-release. Source: Ocskó Gyula: Gépjárműtechnikai szakrajz 2020. 12. 08. Hajdu Flóra

Semipermanent Pins • Semipermanent pin fasteners require application of pressure or the aid of tools for installation or removal. • 2 basic types • machine pins • radial locking pins. • General design rules apply to all types of semipermanent pins: • Avoid conditions in which the direction of vibration parallels the axis of the pin. • Keep the shear plane of the pin a minimum distance of one diameter from the end of the pin. • In applications in which engaged length is at a minimum and appearance is not critical, allow pins to protrude the length of the chamfer at each end for maximum locking effect. 2020. 12. 08. Hajdu Flóra

Semipermanent Pins • Semipermanent pin fasteners require application of pressure or the aid of tools for installation or removal. • 2 basic types • machine pins : hardened and ground dowel pins and commercial straight pins, taper pins, clevis pins, and standard cotter pins. • radial locking pins: solid with grooved surfaces and hollow spring pins • General design rules apply to all types of semipermanent pins: • Avoid conditions in which the direction of vibration parallels the axis of the pin. • Keep the shear plane of the pin a minimum distance of one diameter from the end of the pin. • In applications in which engaged length is at a minimum and appearance is not critical, allow pins to protrude the length of the chamfer at each end for maximum locking effect. 2020. 12. 08. Hajdu Flóra

Machine pins 2020. 12. 08. Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design Hajdu Flóra

Radial Locking Pins • Grooved Straight Pins: Locking action of the grooved pin is provided by parallel, longitudinal grooves uniformly spaced around the pin surface - elastic deformation of the raised groove edges produces a secure force-fit with the hole wall. • Hollow Spring Pins: Resilience of hollow cylinder walls under radial compression forces is the principle under which spiral-wrapped and slotted tubular pins function- exert spring pressure against the hole wall along their entire engaged length to produce a locking action. Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design 2020. 12. 08. Hajdu Flóra scan

Radial locking pins • simpler and cheaper • There are 2 longitudinal slits that are rolled or knocked • Components are drilled together during assembly and the pin is knocked into the drilled hole 2020. 12. 08. Hajdu Flóra

Radial Locking Pins 2020. 12. 08. Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design Hajdu Flóra

Quick-Release Pins • vary widely in head styles, types of locking and release mechanisms, and range of pin lengths • suited for shear-load applications with some degree of tension loading • Types • push-pull pins: made with either a solid or a hollow shank, containing a detent assembly in the form of a locking lug, button, or ball, backed up by some type of resilient core, plug, or spring. The detent member projects from the surface of the pin body until sufficient force is applied in assembly or removal to cause it to retract against the spring action of the resilient core and release the pin for movement. • positive-locking pins: For some quick-release fasteners, the locking action is independent of insertion and removal forces. • heavy-duty cotter pins • single-acting pins • double-acting pins. 2020. 12. 08. Hajdu Flóra

Quick-Release Pins Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design 2020. 12. 08. Hajdu Flóra

Clevis pins • Shaft tolerance h 11, • Hole tolerance H 8 or H 11 • Clearance fit 2020. 12. 08. Hajdu Flóra

Clevis pins assemblies 2020. 12. 08. Hajdu Flóra

Dowel pins • Holding laminated sections together with surfaces either drawn up tight or separated in some fixed relationship. • Fastening machine parts where accuracy of alignment is a primary consideration. • Locking components on shafts, in the form of transverse pin key. • Fit: H 7/m 6, H 8/h 8 2020. 12. 08. Hajdu Flóra

Dowel pins 2020. 12. 08. Hajdu Flóra

Taper pins • Used for light duty service in the attachment of wheels, levers, and similar components to shafts. • High accuracy due to tapering even during frequent disassembling • A secure binding to shock and shape locking • More expensive 2020. 12. 08. Hajdu Flóra

Constructions with pins 2020. 12. 08. Hajdu Flóra

Retaining Rings (snap rings) • Used to provide a removable shoulder to accurately locate, retain, or lock components on shafts and in bores of housings • Easily installed and removed, and are usually made of spring steel • high shear strength and impact capacity. • Number of rings are designed for taking up end play caused by accumulated tolerances or wear in the parts being retained. • 3 categories • tamped retaining rings • wire-formed rings • spiral-wound retaining rings. 2020. 12. 08. Hajdu Flóra

Retaining Rings (snap rings) 2020. 12. 08. Hajdu Flóra Source: C. Jensen, J. D. Helsel, D. R. Short: Engineering Drawing&Design

Stamped Retaining Rings • have a tapered radial width that decreases symmetrically from the center section to the free ends. • The tapered construction permits the rings to remain circular when they are expanded for assembly over a shaft or contracted for insertion into a bored hole or housing. This constant circularity ensures maximum contact surface with the bottom of the groove. • 3 groups: • axially assembled rings: slip over the ends of shafts or down into bores • radially assembled rings: have side openings that permit the rings to be snapped directly into grooves on a shaft • Self-locking rings: do not require grooves 2020. 12. 08. Hajdu Flóra

Stamped Retaining Rings 2020. 12. 08. Hajdu Flóra

Seeger-Rings 2020. 12. 08. Hajdu Flóra

Retaining Rings • Wire-Formed Retaining Rings: a split ring formed and cut from spring wire of uniform cross-sectional size and shape. The wire is cold-drawn or rolled into shape from a continuous coil or bar. Then the gap ends are cut into various configurations for ease of application and removal. • Spiral-wound retaining rings: consist of two or more turns of rectangular material, wound on edge to provide a continuous crimped or uncrimped coil. 2020. 12. 08. Hajdu Flóra

Summary • Keys • Pins • Axial retaining rings • Next week: Shafts, spline shafts

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