U.S. patent number 3,647,231 [Application Number 05/011,090] was granted by the patent office on 1972-03-07 for self-contained hydraulic system for fluid-actuated chuck.
This patent grant is currently assigned to Rohr Corporation. Invention is credited to Thomas W. Schafer.
United States Patent |
3,647,231 |
Schafer |
March 7, 1972 |
SELF-CONTAINED HYDRAULIC SYSTEM FOR FLUID-ACTUATED CHUCK
Abstract
Chuck includes cylindrical housing with central bore and two
sets of holes extending from the bore to side surface of housing,
said sets being spaced apart axially of the housing and the holes
in each set being spaced apart circumferentially thereof. Actuating
pistons are disposed in said holes and project from side surface of
housing, and a drive piston is disposed in bore between two sets of
holes. A collar is mounted on housing for movement axially thereof
and has on its inner side cam surfaces which slope relative to side
surface of housing and respectively engage projecting ends of
actuating pistons in two sets of holes. Fluid disposed in bore
between actuating pistons and drive piston cause latter to move
axially of bore when collar moves axially of housing and thereby
forces one set of actuating piston toward bore while permitting
other set of actuating pistons to move away from bore. A collet
having jaws therein is attached to housing, and shaft connected to
drive piston varies spacing between jaws when drive piston moves in
bore.
Inventors: |
Schafer; Thomas W. (Chula
Vista, CA) |
Assignee: |
Rohr Corporation (Chula Vista,
CA)
|
Family
ID: |
21748845 |
Appl.
No.: |
05/011,090 |
Filed: |
February 13, 1970 |
Current U.S.
Class: |
279/4.06;
279/60 |
Current CPC
Class: |
B23B
31/1223 (20130101); Y10T 279/1241 (20150115); Y10T
279/17615 (20150115) |
Current International
Class: |
B23B
31/12 (20060101); B23b 031/30 () |
Field of
Search: |
;279/4,60,64
;269/25,27,29,30 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Coan; James F.
Claims
What is claimed as new and useful and desired to be secured by U.S.
Letters Patent is:
1. In combination:
a cylindrical housing having a coaxial bore extending from a first
end thereof, and first and second holes spaced apart axially of
said bore and extending laterally therefrom to the side surface of
said housing, said first hole being disposed between said first end
of said housing and said second hole;
a drive piston slidably disposed in said bore between said first
and second holes;
actuating pistons respectively slidably disposed in said first and
second holes with one end thereof projecting from the side surface
of said housing;
a shaft extending axially of said bore and sealably engaged with
said housing at said first end thereof, one end of said shaft being
connected to said drive piston and the other end projecting from
said first end of said housing, at least the portion of said shaft
between said first hole and said drive piston being spaced from the
wall of said bore;
fluid disposed in the first space extending between the actuating
piston in said first hole and the adjacent end of said drive
piston, and in the second space extending between the actuating
piston in said second hole and the adjacent end of said drive
piston;
a collar disposed around said housing and mounted thereon for
movement axially thereof, a pair of circumferentially extending,
inwardly convergent cam surfaces being formed on the inner wall of
said collar and spaced apart axially thereof so as to respectively
engage said actuating pistons; and
clamping means attached to said first end of said housing and
comprising at least two jaws operatively connected to said shaft so
that when it moves axially of said bore the distance between said
jaws varies.
2. The combination defined in claim 1 wherein said clamping means
comprises a collet one end of which is attached to said first end
of said housing in coaxial relation therewith, a plurality of slots
extending axially of the inner wall of said collar and diverging
from the longitudinal axis of said collar in the direction of said
housing, said jaws being wedge shaped and respectively slidably
disposed in said slots.
3. A chuck comprising:
a cylindrical housing having a coaxial bore extending from a first
end thereof, two sets of holes extending laterally from said bore
to the side surface of said housing and spaced apart
circumferentially thereof, the longitudinal axes of the holes of
said sets respectively lying in two planes disposed perpendicular
to the longitudinal axis of said housing and spaced apart axially
thereof, the portion of said bore adjacent said first end of said
housing having a reduced diameter and a circumferentially extending
thread being formed on the side surface of said housing between
said sets of holes;
a drive piston slidably disposed within said bore between said two
sets of holes;
a shaft slidably mounted in the reduced diameter portion of said
bore for movement axially thereof, one end of said shaft being
connected to said drive piston and the other end thereof projecting
from said first end of said housing;
actuating pistons respectively slidably disposed in said holes with
one end thereof projecting from the side surface of said
housing;
a collar disposed around said housing and the middle portion of the
inner wall of which is provided with a thread engaged with the
thread on said housing, a pair of circumferentially extending cam
surfaces being respectively formed on the inner wall of said collar
on opposite sides of said thread thereon and each diverging from
the side surface of said housing in the direction of the adjacent
end of said collar, the actuating pistons in the two sets of said
holes being respectively engaged with said cam surfaces;
a collet one end of which is attached to said first end of said
housing, said collet being coaxial with said housing and having in
its inner wall a plurality of axially extending slots the
longitudinal axes of which are inclined relative to the
longitudinal axis of said collet; and
a plurality of wedge-shaped jaws respectively slidably disposed in
said slots and operatively connected to said shaft.
Description
SUMMARY OF THE INVENTION
This invention relates to a device for changing rotary motion to
linear motion and, more particularly, to a chuck the jaws of which
can readily be tightened on a drill or the like without a chuck
wrench.
In a preferred embodiment of the invention, a bore extends between
the ends of a cylindrical housing and a plurality of holes extend
radially from this bore to the side surface of the housing. The
bore has a reduced diameter portion at one end thereof and its
other end is closed by an end member which is attached to the
housing by means of screws and which comprises a threaded hole
adapted to receive the end of the spindle of a drill press or the
like. The holes which extend from the bore to the side surface of
the housing are arranged in two sets spaced apart axially of said
housing, the longitudinal axes of the holes in the sets
respectively lying in two parallel planes each disposed
perpendicular to the longitudinal axis of the housing and the holes
in each set being evenly spaced apart circumferentially of said
bore. Slidably disposed in the bore between the two sets of holes
is a drive piston, and slidably disposed in each of the holes is an
actuating piston. A shaft is slidably mounted in the reduced
diameter portion of the housing and is connected to the drive
piston at one end thereof. The other end of the shaft projects from
the end of the housing and is operatively connected to a plurality
of wedge-shaped jaws which are mounted in a collet one end of which
is threadedly engaged with the housing. The portion of the side
surface of the housing which lies between the two sets of holes is
formed with a circumferentially extending helical thread, and a
collar is disposed around the housing and has on its inner side a
threaded portion which engages the thread on said housing. On each
side of the threaded portion of the inner side of the collar is a
cam surface which diverges from the adjacent side surface of the
housing in the direction of the adjacent end of the collar, the
aforesaid actuating pistons projecting from the two sets of holes
which extend to the side surface of the housing and respectively
engaging the two cam surfaces on the collar. Thus when the collar
is turned around the housing the cam surfaces on its inner side are
moved axially of the housing, and the actuating pistons in one set
of the housing holes are forced toward the housing bore by the cam
surface engaged therewith while the other cam surface moves away
from the side surface of the housing at the portion thereof where
the other actuating pistons are located. Hydraulic fluid is
disposed in the two cavities between the inner ends of the
actuating pistons and the drive piston in the housing bore, so that
when one set of actuating pistons moves inwardly the drive piston
is forced toward the holes in which the other actuating pistons are
positioned. The last mentioned actuating pistons are simultaneously
moved away from the housing bore by the hydraulic fluid which is
disposed in the space between said pistons and the drive piston.
The jaws in the collet, being connected to the drive piston by
means of the aforesaid shaft, are also simultaneously moved either
toward or away from one another, depending upon the direction of
rotation of the collar relative to the housing.
The construction and manner of operation of the preferred
embodiment of the invention will be explained in further detail in
the following specification wherein reference is made to the
accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end view of the preferred embodiment of the
invention.
FIG. 2 is a longitudinal sectional view of the same embodiment,
taken along the plane represented by line 2--2 in FIG. 1 and in the
direction indicated by arrows.
DETAILED DESCRIPTION
In the drawing reference number 10 designates generally a housing
which comprises a cylindrical member 12 having a bore 14 extending
between the ends thereof, and which also comprises an end cap 16
which is fixedly secured to one end of said member 12 by a
plurality of screws 18 and is formed on one side with a cylindrical
projection adapted to fit within the adjacent portion of said bore
and on the other side with another cylindrical projection having a
threaded hole therein. The surface of end cap 16 which abuts the
end of member 12 contains an annular groove in which a seal ring 19
is seated. Bore 14 is coaxial with housing 10 and with the threaded
hole in the end cap thereof, and it has a reduced diameter at the
end of said housing which is lowermost in FIG. 2, which end will be
referred to hereinafter as the first end of the housing. Four holes
20 (which are referred to hereinafter as the first holes and only
two of which are illustrated) extend from the side surface 22 of
housing 10 to the portion of bore 14 next to its reduced diameter
portion, the longitudinal axes of said holes being evenly spaced
apart circumferentially of said bore and lying in a plane disposed
perpendicular to the longitudinal axis thereof. Another set of four
holes 24 (which are referred to hereinafter as the second holes and
only two of which are illustrated) extend from side surface 22 to
bore 14, the longitudinal axes of these holes also being evenly
spaced apart circumferentially of the bore and lying in a second
plane which is disposed perpendicular to the longitudinal axis of
the latter and spaced from the plane including the axes of the
first holes. Adjacent bore 14 each hole 20, 24 has a reduced
diameter.
A cylindrical shaft 26 is slidably mounted in the reduced diameter
portion of bore 14 and extends into the larger diameter portion of
the bore as illustrated. Integrally formed on the inner end of this
shaft is a drive piston 28 having in its sidewall two
circumferentially extending grooves for seal rings 30, 32. A seal
ring 34 is also seated in a groove formed in a projection 36 on the
first end of housing 10.
The side surface of housing 10 is formed with two threaded portions
38, 40 which are respectively disposed at the first end of said
housing and between the first and second holes 20, 24. The large
diameter end of a tapered collet 42 is provided at its inner wall
with threads which engage the threaded first end of housing 10, the
collet thus being held in fixed, coaxial relation with the housing
and bore 14 therein. Evenly spaced apart circumferentially of the
inner wall of collet 42 and extending axially thereof are three
slots (only two illustrated) each of which comprises a relatively
wide portion 44 and a narrower portion 46, said slots converging
toward the longitudinal axis of the collet as the distance from the
first end of housing 10 increases and terminating a short distance
from the free end of the collet. Wedge-shaped jaws 48 are
respectively slidably engaged within the aforesaid slots in collet
42 so that they can move longitudinally thereof, each jaw
comprising a portion which conformably fits in the wide portion 44
of the associated slot and an integral portion which conformably
fits in the narrow portion 46 of said slot and projects from the
latter toward the longitudinal axis of the collet. The inner edges
50 of jaws 48 may be serrated as illustrated to enhance their
ability to grip the shanks of drills and the like. Another groove
52 extends transversely across the inner edge of each jaw at the
middle portion thereof and toward the wall of the collet, with the
sidewalls of this groove being parallel to each other and
perpendicular to the longitudinal axis of said collet. Reference
number 54 designates generally a screw the shank 56 of which is
threadedly engaged within a hole coaxially formed in the outer end
of shaft 26 and the head 58 of which is slidably seated within
slots 52 in jaws 48.
Slidably disposed in each first hole 20 and each second hole 24 is
an actuating piston 60, 62 which has a seal ring 63, 64 seated in a
slot extending circumferentially about its periphery adjacent the
inner end thereof. The outer end of each actuating piston is
rounded and projects from the side surface 22 of housing 10. The
inner side of a collar, designated generally by reference number
66, includes a threaded section which is located equidistant from
the ends of said collar and which is engaged with the threaded
portion 40 of the side surface of housing 10. On each side of the
threaded section of the inner side of the collar is a
circumferentially extending cam surface 68, 70 which is inwardly
convergent (i.e., each cam surface diverges from the side surface
22 of housing 10 in the direction of the adjacent end of said
collar, as illustrated in FIG. 2, and a circumferentially extending
flange 72, 74 projects inwardly from each cam surface at the
respective ends of said collar. Preferably the side surface 76 of
the collar is knurled.
Two filling holes (not shown) respectively extend through the wall
of housing 10 to the space 78 which extends between the inner ends
of the actuating pistons 62 in holes 24 to the adjacent end of
drive piston 28 and to the space 80 which extends between the inner
ends of the actuating pistons 60 in holes 20 to the other end of
said drive piston. Suitable means such as setscrews (not shown) are
removably engaged in the outer ends of the filling holes, thus
permitting said spaces 78 and 80 to be filled with a suitable
hydraulic fluid.
OPERATION
It will be noted in the drawing that the cam surfaces on the inner
side of collar 66 are spaced apart at such distance that the outer
ends of the actuating pistons 60, 62 in the two sets of holes 20,
24 are respectively engaged therewith. When collar 66 is turned
about housing 10 it of course also moves axially thereof. Thus, for
example, collar 66 can be moved from its illustrated position in
the drawing to a position wherein it is closer to the first end of
the housing (i.e., closer to the lower end of the housing in said
drawing). Such axial movement of the collar causes cam surface 70
to push the actuating pistons 60 in first holes 20 toward bore 14,
while the actuating pistons 62 in second holes 24 are allowed to
move away from said bore. As actuating pistons 60 move inwardly
drive piston 28 is forced away from the first end of housing 10 by
the pressure exerted thereon by the hydraulic fluid in space 80.
Since jaws 48 are connected to the drive piston by the shaft 26,
they are consequently moved toward the first end of housing 10.
Furthermore, since the collet slots in which the jaws are
respectively engaged diverge in the direction of housing 10, the
spacing between said jaws is simultaneously increased. Obviously if
collar 66 is turned in the opposite direction relative to housing
10, jaws 48 are moved away from the latter and toward the
longitudinal axis of collet 42. The mechanical advantage provided
by cam surface 68 of collar 66 acting against actuating pistons 62
to move them toward bore 14 results in high clamping pressure
against a drill or other article disposed between jaws 48.
Various changes in the arrangement of the described and illustrated
embodiment of the invention can obviously be made without departing
from the concepts of its design and operation. Hence the scope of
the disclosed invention should be considered to be limited only by
the terms of the claims appended hereto.
* * * * *