U.S. patent number 3,766,812 [Application Number 05/282,432] was granted by the patent office on 1973-10-23 for clamp for a member with an internal flange.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to John C. McEwen.
United States Patent |
3,766,812 |
McEwen |
October 23, 1973 |
CLAMP FOR A MEMBER WITH AN INTERNAL FLANGE
Abstract
A clamp for a member with an internal flange which includes two
nuts mounted on a threaded stud extending from a clamping surface.
The outside nut has a plurality of shafts spaced equidistantly
around the stud and extending axially toward the inside nut. On
each shaft a wing is free to pivot inside or outside the outer
diameter of the nut. The inside nut has a plurality of stops, one
projecting between each pair of wings, and requires significant
torque to rotate. Therefore as the outside nut is tightened, the
wings are spread by the stops to engage the inner flange and hold
the clamped member against the clamping surface; and as the outside
nut is loosened the stops retract the wings so the clamped piece
can be removed from the stud.
Inventors: |
McEwen; John C. (Indianapolis,
IN) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
23081494 |
Appl.
No.: |
05/282,432 |
Filed: |
August 21, 1972 |
Current U.S.
Class: |
82/165; 279/2.24;
269/49; 279/2.19 |
Current CPC
Class: |
B23B
31/4073 (20130101); Y10T 279/1095 (20150115); Y10T
82/26 (20150115); Y10T 279/1074 (20150115) |
Current International
Class: |
B23B
31/00 (20060101); B23B 31/40 (20060101); B23b
033/00 () |
Field of
Search: |
;82/4R,44 ;269/49,52
;279/2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Vlachos; Leonidas
Claims
I claim:
1. A clamp comprising, in combination:
a member with a clamping surface;
a threaded stud projecting perpendicularly from the clamping
surface;
a first nut on the threaded stud;
a plurality of wings pivotally mounted on the first nut for
pivoting through a predetermined sector about axes parallel to the
threaded stud, each wing having a first contacting surface for
pivoting radially outward from the threaded stud and a second
contacting surface for pivoting radially inward toward the threaded
stud;
a second nut on the threaded stud;
a plurality of stops on the second nut, each stop projecting
between two wings for engagement with the first contacting surface
of a wing when the first nut is rotated for advancement toward the
clamping surface and engagement with the second contacting surface
of a wing when the first nut is rotated for recession from the
clamping surface.
2. A clamp to hold a member with an internal flange to a faceplate
which comprises, in combination:
a stud projecting from the faceplate;
a first nut threadably mounted on the stud, the first nut having an
outer diameter smaller than the inner diameter of the internal
flange;
a plurality of wings pivotally mounted on the first nut, each wing
extending a distance from the axis of the stud which varies as the
wing is pivoted;
a second nut threadably mounted on the stud, the second nut having
an outer diameter smaller than the inner diameter of the internal
flange and exhibiting frictional resistance to rotation on the
stud;
and a plurality of stops on the second nut, the stops projecting
between adjacent wings on the first nut and capable of interaction
with the wings upon rotation of the first nut toward the faceplate
to spread the wings outside the inner diameter of the internal
flange and upon rotation of the first nut away from the faceplate
to retract the wings within the inner diameter of the internal
flange.
Description
SUMMARY OF THE INVENTION
My invention concerns a clamp to hold a piece with an internal
flange. The invention arose as the solution to a problem of a lathe
operator who must clamp internally flanged workpieces to the lathe
faceplate. This has been done in the past with a nut and C-washer
on a threaded stud or shaft projecting from a clamping surface on
the lathe faceplate. The C washer, however, is a loose part that is
easily dropped while the clamp is being used or lost when the clamp
is not being used. Sometimes a swing clamp is used in place of the
C washer. Repeated lifting of this heavy clamp, however, is tiring
for the lathe operator. In addition, a wrench must always be handy
to tighten the nut.
My invention, however, consists of a small clamp which remains on
the stud at all times and has no loose pieces to be lost. Although
it can be used generally with a wrench, it can be adapted for use
on a lathe so that no wrench is needed. A preferred embodiment of
my invention is described in more detail in the accompanying
drawings and the following specification.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a preferred embodiment of my invention.
FIG. 2 is an exploded view of the embodiment shown in FIG. 1.
FIG. 3 is a view along the line 3--3 in FIG. 1 when the clamp is
being tightened.
FIG. 4 is a view along line 3--3 in FIG. 1 when the clamp is being
loosened.
FIG. 5 shows my invention mounted for use on a lathe.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a threaded stud 2 is mounted in a wall such as
a lathe faceplate 4 perpendicular to a clamping surface 6 of the
faceplate 4. A nut 8 is threadably mounted on the stud 2. Details
of this nut, as well as of other parts of the clamp, can be seen
more clearly in FIG. 2. The nut 8 has flats 10 for receiving a
wrench. A plurality of threaded shafts 12, in this embodiment shown
as two in number, project from the nut 8 toward the clamping
surface 6. The shafts 12 are spaced equidistantly apart in a circle
around the stud 2; in this case the shafts 12 are 180.degree.
apart. On each of the shafts 12 is threaded a wing 14, which is
free to pivot through a small arc about its shaft 12. Each wing 14
has a first contacting surface 20 comparatively far from the
pivoting axis, a second contacting surface 22 closer to the
pivoting axis and on the other side of it and a third contacting
surface 24 connecting the first contact surface 20 with the second
contacting surface 22.
A teaser nut 16 is threadably mounted on the stud 2 and bears a
plurality of stops 18 which project toward the nut 8. The number of
stops 18 is equal to the number of wings 14; and the stops 18 are
equally spaced around the stud 2 so that each stop 18 projects
between two of the wings 14. Nut 16 is split at 19 for resilience
and is sufficiently tight on the stud that it exerts a significant
resistance to rotation.
As the nut 8 is rotated in a direction to move it along the stud 2
toward the clamping surface 6, the contacting surfaces 20 of the
wings 14 contact the stops 18 and are pivoted outward by the stops
18 because of the torque required to drive nut 16 until a part of
the contacting surfaces 24 abut the stud 2 and prevent further
spreading of the wings 14. With the wings 14 in this position, as
shown in FIG. 3, they extend farther in a radial direction than the
outer diameter of the nut 8 or the teaser nut 16 and cause the
teaser nut 16 to rotate along with the nut 8. If the direction of
rotation of nut 8 is reversed, the contacting surfaces 22 of the
wings 14 are pushed against the stops 18; and the wings 14 are
retracted into the position shown in FIG. 4, where no portion of
them extends beyond the outer diameter of the nut 8 or the teaser
nut 16. With the clamp in this position the teaser nut 16 rotates
with the nut 8 in its new direction.
Referring again to FIG. 1, the clamp is used with the workpiece 26
which has an internal flange 28 defining a hole 30 which is
slightly larger than the outside diameter of the nut 8 and teaser
nut 16. With the clamp in the position shown in FIG. 4, the
workpiece 26 is slipped over the clamp and stud 2 until it abuts
the clamping surface 6 of faceplate 4. As the nut 8 is rotated to
move toward the workpiece 26, the wings 14 are spread. These wings
14 abut the inner flange 28 of the workpiece 26; and the nut 8 is
tightened on the stud 2 to hold the workpiece 26 in place by
clamping between the wings 14 and the faceplate 4. When it is
desired to release the workpiece 26 the nut 8 is rotated to loosen
its pressure and the wings 14 are thus retracted so that the
workpiece 26 can be slipped off over the clamps.
In FIG. 5, the clamp is shown installed on a lathe 32 for cutting
by tools 52. The threaded stud 2 is hollow; and through it extends
a shaft 34. The stud 2 is fixed to the faceplate 4, which is turned
by a motor, not shown; and the shaft 34 is turned by a hand wheel
36 through shaft 38, pulley 40, belt 42 and pulley 44. A wrench
member 46, which engages the flats 10 of nut 8, is held on the end
of the shaft 34 by a pin 48. The wrench member 46 causes the nut 8
to turn with the shaft 34; and, since its outer diameter is no
larger than the outer diameter of the nut 8, it does not interfere
with the operation of the clamp.
To use the lathe, the operator slides the workpiece 26 over the
clamp. He then turns the hand wheel 36 in one direction until the
wings 14 clamp the workpiece 26 tightly against the lathe faceplate
40. The motor of the lathe 32 will then turn the workpiece 26. When
the operator decides to remove the workpiece 26 from the lathe 32,
he stops the lathe and turns the hand wheel 36 in the direction
opposite to that for tightening and thus loosens the nut 8 to
retract the wings 14.
It can be seen that my clamp is a useful device with other possible
embodiments and applications that will occur to those skilled in
the art. Therefore, the invention should not be limited to the
embodiments shown.
* * * * *