Ratchet mechanism 5
Bicycle free-wheel.
The blue sprocket receives motion from the pedaling bicyclist. The
yellow hub rotates only when the sprocket rotates clockwise.
Clockwise rotation of the yellow hub has no inflection to the blue
sprocket.
The red pawl is always pressed toward the sprocket’s teeth by a
spring. In reality two pawls are used.
Roller overrunning clutch 2
Green outter disk and blue inner disk rotate around a fixed axis.
The arrows show which link is the driving at different times.
When the outter disk is driving, its two way rotation can be transmitted
to the inner disk only in clockwise direction.
When the inner disk is driving, its two way rotation can be transmitted to
the outter disk only in anticlockwise direction.
Two way overrunning clutch 1
Blue outter disk and pink fork rotate around a fixed axis.
Green inner disk rotates idly on the pink fork.
The arrows show which link is the driving at different times.
1. When the blue outter disk is driving, its rotation of both directions is
transmitted to the green inner disk by wedging of the rollers between
the blue outter disk and the green inner disk (orange rollers for
anticlockwise direction, yellow rollers for clockwise direction).
The rotation of the green inner disk is transmitted to the pink fork by flexible contact via
springs, red bushes and rollers (yellow rollers for clockwise direction, orange rollers for
anticlockwise direction).
2. When the fork is driving, its rotation of both directions is transmitted to the green inner
disk by flexible contact via rollers, red bushes and springs (orange rollers for clockwise
direction, yellow rollers for anticlockwise direction)
The rotation can not transmitted to the blue outter disk because the wedging does not
happen.
3. When the green inner disk is driving, its rotation of both directions is transmitted to the
blue outter disk by wedging of the rollers between the blue outter disk and the green inner
disk (orange rollers for clockwise direction, yellow rollers for anticlockwise direction).
The rotation of the green inner disk is transmitted to the pink fork by flexible contact via
springs, red bushes and rollers (yellow rollers for clockwise direction, orange rollers for
anticlockwise direction).
In brief, the rotation of two directions can be transmitted from the outter disk to the fork. The
inverse is impossible. The fork and the inner disk always rotate together.
If the outter disk is kept immobile, the rotation can be transmitted only from the fork to the
inner disk. The inverse is impossible, causing jam of the mechanism. So the inner disk can
not act as a driving link.
Two way overrunning clutch 2
Blue outter disk and pink fork rotate around a fixed axis.
Green inner disk of oval shape rotates idly on the pink fork.
Brown flat springs force rollers into wedgeshaped gaps between the
outter and inner disks.
The arrows show which link is the driving at different times.
The rotation of two directions can be transmitted from the outter disk
to the fork. The inverse is impossible. The fork and the inner disk always rotate together.
This is an embodiment of the mechanism shown in “Two way overrunning clutch 1”
Roller overrunning clutch 3
Blue outter disk and pink fork rotate around a fixed axis.
Green inner disk rotates idly on the pink fork.
The arrows show which link is the driving at different times.
1. When the blue outter disk is driving, its anticlockwise rotation is
transmitted to the green inner disk by wedging of the yellow rollers
between the blue outter disk and the green inner disk.
Clockwise rotation of the blue outter disk can not be transmitted to the pink fork.
2. When the fork is driving, its rotation of both directions is transmitted to the green inner
disk by flexible contact via yellow rollers, red bushes and springs (for clockwise direction) or
by direct contact between the fork and the green inner disk (for anticlockwise direction).
The rotation can not transmitted to the blue outter disk because the wedging does not
happen.
3. When the green inner disk is driving, its clockwise rotation is transmitted to the blue
outter disk by wedging of the yellow rollers between the blue outter disk and the green inner
disk. Anticlockwise rotation of the green inner disk can not be transmitted to the blue outter
disk.
The rotation of the green inner disk is transmitted to the pink fork by flexible contact via
springs, red bushes and yellow rollers (for anticlockwise direction) or by direct contact
between the green inner disk and the fork (for clockwise direction)
Ball overrunning clutch 1
Blue and green shafts rotate around a fixed axis.
The red flat springs always force the yellow balls into
wedgeshaped gaps between the shafts.
The arrows show which link is the driving at different times.
When the blue shaft is driving, its two way rotation can be
transmitted to the green shaft only in anticlockwise direction.
When the green shaft is driving, its two way rotation can be
transmitted to the blue shaft only in clockwise direction.
Sprag overrunning clutch 1
Blue and green shafts rotate around a fixed axis.
Blue springs and red pins maintain contact between yellow sprags
and the two shafts.
The arrows show which link is the driving at different times.
When the blue shaft is driving, its two way rotation can be
transmitted to the green shaft only in clockwise direction.
When the green shaft is driving, its two way rotation can be transmitted to the blue shaft
only in anticlockwise direction.
Sprag overrunning clutch 2
Blue and green shafts rotate around a fixed axis.
Copper springs maintain contact between yellow sprags, pink pins
and the two shafts.
The arrows show which link is the driving at different times.
When the blue shaft is driving, its two way rotation can be
transmitted to the green shaft only in clockwise direction.
When the green shaft is driving, its two way rotation can be transmitted to the blue shaft
only in anticlockwise direction.
Sprag overrunning clutch 3
Blue and green shafts rotate around a fixed axis.
Red spring maintains contact between yellow sprag, pink pin and the
two shafts.
The arrows show which link is the driving at different times.
When the blue shaft is driving, its two way rotation can be transmitted
to the green shaft only in clockwise direction.
When the green shaft is driving, its two way rotation can be transmitted to the blue shaft
only in anticlockwise direction.
Sprag overrunning clutch 4
Blue and green shafts rotate around a fixed axis.
Red spring maintains contact between yellow sprag and V-shaped
groove of the green shaft.
The arrows show which link is the driving at different times.
When the blue shaft is driving, its two way rotation can be transmitted
to the green shaft only in clockwise direction.
When the green shaft is driving, its two way rotation can be transmitted
to the blue shaft only in antclockwise direction.
If the green shaft is kept immobile, the blue shaft can rotate only anticlockwise. It is braked
automatically when rotating clockwise (mechanism for preventing reverse rotation).
Screw overrunning clutch 1
Blue and green shafts rotate around a fixed axis.
Yellow nut of male cone has a helical joint (right hand thread) with
the blue shaft.
Red torsion spring tends to turn the yellow nut clockwise thus
maintains contact for cone surfaces of the yellow nut and the green
shaft.
The arrows show which link is the driving at different times.
When the blue shaft is driving and rotates anticlockwise, the green
shaft tends to keep the nut immobile. The latter tends to move
towards the green shaft, contact force at cone surfaces increases, the green shaft rotates
together with the blue shaft.
When the blue shaft is driving and rotates clockwise, the green shaft tends to keep the nut
immobile. The latter tends to move apart from the green shaft, contact force at cone surface
decreases, the green shaft stays immobile.
In brief:
- When the blue shaft is driving, its two way rotation can be transmitted to the green shaft
only in anticlockwise direction.
- When the green shaft is driving, its two way rotation can be transmitted to the blue shaft
only in clockwise direction.
- If the green shaft is kept immobile, the blue shaft can rotate only anticlockwise. It is braked
automatically when rotating clockwise(mechanism for preventing reverse rotation).
This mechanism is created purely on computer and needs to be verified in practice.
Screw gear overrunning clutch
Green ring and blue gear rotate around a fixed axis.
The ring carries two yellow gear shafts with brown cones.
The arrows show which link is the driving at different times.
1. If the green ring is driving:
- When the ring rotates anticlockwise, gearing forces (axial
components) push the yellow gear shafts towards the femal cones of the ring, the yellow
gear shafts can not rotate and make the blue gear rotate.
- When the ring rotates clockwise, gearing forces push the yellow gear shafts away from the
femal cones of the ring, the yellow gear shafts rotate idly and the blue gear is kept immobile
by load applied on it.
2. If the blue gear is driving:
- When the blue gear rotates anticlockwise, gearing forces push the yellow gear shafts
away from the femal cones of the ring, the yellow gear shafts rotate idly and the ring is kept
immobile by load applied on it.
- When the blue gear rotates clockwise, gearing forces push the yellow gear shafts towards
the femal cones of the ring, the yellow gear shafts can not rotate and make the ring rotate.
For an embodiment of this mechanism the three helical gears are replaced by a non self
locking worm drive (one worm gear and two worms).
Roller overrunning clutch 3
Input: blue shaft rotating two directions.
Output: green shaft rotates with the input shaft only in the direction
set by the pink lever.
The orange pins always force the red roller into wedgeshaped gaps
between the input and output shafts.
The spring of the blue pin must be strong enough for positioning the
pink lever.
Two-way anti-reverse transmission 1a
Pink input shaft transmits rotation to output green shaft in both
directions.
Reverse transmission is impossible because yellow rollers wedge
between the fixed outter rim and the green shaft.
The mechanism has self-locking feature like worm drive but
transmission ratio is 1/1.
It can be used for motion control system where servo motor needs a
rest (interrupting electric supply) when motion control is not required.
For more see: “Two way overrunning clutch 1”
http://youtu.be/-Y_SQGMRx8k
Two-way anti-reverse transmission 1b
This is an embodiment of the mechanism shown in “Two-way antireverse
transmission 1a”
http://youtu.be/wZjoNIkYQqM
Pink input shaft transmits rotation to output green shaft in both
directions.
Reverse transmission is impossible because rollers wedge between
the fixed outter rim and the green shaft.
The mechanism has self-locking feature like worm drive but transmission ratio is 1/1.
It can be used for motion control system where servo motor needs a rest (interrupting
electric supply) when motion control is not required.
For more see: “Two way overrunning clutch 2”