Mandrel assembly for use with a rotary tool
View Patent ↗A mandrel assembly may be used with a rotary power tool to provide a reliable and stable connection between the rotary tool and a tool accessory. The mandrel assembly provides a quick-connect/quick-release connection between the tool output shaft and the accessory via a clamping action. In particular, the mandrel assembly is movable between first and second configurations. In the first configuration, the accessory may clamped between a clamping element formed on one end of the mandrel and a collar which surrounds the mandrel. In the second configuration, the accessory may be loaded onto or detached from the mandrel assembly.
1 . A mandrel assembly, comprising:
a mandrel including
a mandrel first end having a mandrel clamping element,
a mandrel second end that is opposite the mandrel first end,
a longitudinal axis that extends through the mandrel first end and the mandrel second end, and
a slot provided in an outer surface of the mandrel;
a collar that surrounds the mandrel, the collar including
a collar first end,
a collar second end that is opposite the first end, and
a sidewall that extends between the collar first end and the collar second end, the sidewall including an inner surface that defines a bore, the bore opening at the collar first end and the collar second end, the bore having a step change in diameter that defines a collar inner shoulder, and
a pin that protrudes from a surface of the bore and is received in the slot;
a retention washer fixed to the mandrel between the slot and the mandrel second end; and
a spring that surrounds the mandrel, the spring extending between the retention washer and the collar inner shoulder,
wherein
when the collar is moved relative to the mandrel in a first direction, the slot is configured to permit the mandrel to move relative to the collar in both rotation through a first angle about the longitudinal axis and translation in a second direction, the second direction being opposite the first direction, and
when the collar is moved relative to the mandrel in the second direction, the slot is configured to permit the mandrel to move relative to the collar in both rotation through a second angle about the longitudinal axis and translation in the first direction, the second angle being opposite the first angle.
2 . The mandrel assembly of claim 1 , wherein
at a first location of the slot, the slot is configured so that a biasing force of the spring maintains the mandrel clamping element at a first distance from the collar,
at a second location of the slot, the slot is configured so that a biasing force of the spring maintains the mandrel clamping element at a second distance from the collar, and
the second distance is greater than the first distance.
3 . The mandrel assembly of claim 1 , wherein when the collar is moved relative to the mandrel in the first direction, the slot is configured to permit the mandrel to
translate linearly in the second direction, then rotate through the first angle, and then translate linearly in the second direction.
4 . The mandrel assembly of claim 1 , wherein the first angle is 90 degrees.
5 . The mandrel assembly of claim 1 , wherein the second angle is 90 degrees.
6 . The mandrel assembly of claim 1 , wherein the first and second directions are parallel to the longitudinal axis.
7 . The mandrel assembly of claim 1 , wherein the slot is configured so that as the mandrel rotates through one of the first angle and the second angle, the mandrel also translates in a direction parallel to the longitudinal axis.
8 . The mandrel assembly of claim 1 , wherein the slot includes
a first slot portion that extends linearly and in a direction parallel to the longitudinal axis,
a second slot portion that adjoins the first slot portion, the second slot portion extending in a direction parallel to the longitudinal axis and circumferentially along a curved path,
a third slot portion that adjoins the second slot portion, the third slot portion extending linearly and circumferentially, and
fourth slot portion that adjoins the third slot portion, the fourth slot portion extending linearly and axially.
9 . The mandrel assembly of claim 8 , wherein
the second and third slot portions in combination provide a path that when traveled by the pin results in a 90 degree rotation of the mandrel about the longitudinal axis.
10 . The mandrel assembly of claim 8 , wherein
movement of the pin in the first slot portion corresponds to a motion of the mandrel relative to the collar in which the mandrel clamping element is translated in the first direction,
movement of the pin in the second slot portion corresponds to a motion of the mandrel relative to the collar in which the mandrel clamping element is translated in the first direction and in which the mandrel rotates about the longitudinal axis,
movement of the pin in the third slot portion corresponds to a motion of the mandrel relative to the collar in which the mandrel rotates about the longitudinal axis, and
movement of the pin in the fourth slot portion corresponds to a motion of the mandrel relative to the collar in which the mandrel clamping element is translated in the first direction.
11 . The mandrel assembly of claim 8 , wherein
the first slot portion initiates at the mandrel first end,
the second slot portion, the third slot portion and the fourth slot portion are disposed between the mandrel first end and a mandrel shoulder, and
the mandrel shoulder is disposed between the mandrel first end and a point of the mandrel that is midway between the mandrel first end and the mandrel second end.
12 . The mandrel assembly of claim 1 , wherein
the collar includes posts that protrude from the collar first end in a direction parallel to the longitudinal axis,
the collar includes lands disposed between each adjacent pair of posts,
upon a relative movement in a direction parallel to the longitudinal axis between the collar and the mandrel, the slot is configured to permit the mandrel to move relative to the collar
from a first configuration in which the mandrel clamping element is aligned with and abutting the lands,
to a second configuration in which the mandrel clamping element is aligned with the posts and spaced apart from the posts.
13 . The mandrel assembly of claim 1 , wherein the slot includes
a first mandrel location corresponding to a first locked position in which a biasing force of the spring maintains the clamping element in a retracted configuration relative to the collar, and
a second mandrel location corresponding to a second locked position in which a biasing force of the spring maintains the clamping element in a retracted configuration relative to the collar.
14 . The mandrel assembly of claim 13 , wherein the first mandrel location corresponds to one end of the slot.
15 . The mandrel location of claim 13 , wherein the second mandrel location is disposed at a location between, and spaced apart from, each end of the slot.
16 . The mandrel assembly of claim 13 , wherein
the first locked position corresponds to a dead end of the slot, and
the second locked position corresponds to a step portion of the slot.