U.S. patent number 3,669,089 [Application Number 05/098,654] was granted by the patent office on 1972-06-13 for swing arm for holding a dressing device.
Invention is credited to Henry F. Swenson.
United States Patent |
3,669,089 |
Swenson |
June 13, 1972 |
SWING ARM FOR HOLDING A DRESSING DEVICE
Abstract
A swing arm for holding a dressing device is adapted for
mounting on a column or base portion of a machine tool. The
swinging end of the arm is disposed to hold a threaded dressing
member while the arm is swung in an arc around a pivot shaft. The
pivot shaft retains a pivot joint which includes a roller thrust
bearing disposed between the fixed and the movable member with a
spring-type washer urging the fixed and the rotatable member
together in a determined frictional relationship. An O-ring is
seated in a groove formed at the roller raceway so as to seal the
thrust bearing as well as provide a dust seal and vibration
dampener.
Inventors: |
Swenson; Henry F. (Roseland,
NJ) |
Family
ID: |
22270329 |
Appl.
No.: |
05/098,654 |
Filed: |
December 16, 1970 |
Current U.S.
Class: |
125/11.01;
403/73 |
Current CPC
Class: |
B24B
53/12 (20130101); Y10T 403/32172 (20150115) |
Current International
Class: |
B24B
53/12 (20060101); B24b 053/12 () |
Field of
Search: |
;125/11,11A ;287/101
;308/3A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Whitehead; Harold D.
Claims
What is claimed is:
1. A swing arm assembly for holding a dressing device for grinding
wheels and the like, said swing arm assembly including: (a) a fixed
support member adapted for removable attachment to a base, column
and like fixed portions of a machine tool carrying the grinding
wheel to be dressed, said fixed member having one end formed to
provide a determined flat surface and with a first aperture formed
through this flat surface portion, this first aperture having its
axis normal to the plane of the flat surface; (b) a swing member
pivotally attached to and supported by one end of the fixed support
member, said swing member having a flat surface portion formed at
its pivoted end and with a second aperture formed through this flat
surface, said second aperture having its axis normal to the plane
of said flat surface; (c) a pivot pin providing the pivoted support
of the swing arm on the fixed support member, said pivot pin
mounted in and through said first and second apertures; (d) roller
thrust bearing having opposed raceway members and mounted on the
pivot pin and between the opposed flat faces of the fixed and swing
members; (e) a resilient ring seal in a slightly stretched
condition engaged in a groove formed by a chamfer on facing outer
edges of the opposed raceway members of the thrust bearing, said
seal preventing dust, dirt and the like from entering the bearing
while also providing a brake action to the relative rotative
movement of the thrust bearing raceways; (f) biasing means for
urging the fixed and swing members toward each other while also
providing a vibration dampner and pre-load to the thrust bearing,
and (g) holding means provided on the distal end of the swinging
arm for holding a dressing device for a grinding wheel, the holding
means in combination with the dressing device adapted to be
adjustably moved to a selected position in a plane parallel to the
plane of the movement of the swing arm around the pivot pin.
2. A swing arm assembly for holding a dressing device as in claim 1
in which the pivot pin is a headed pin having thread means provided
at least at the opposite shank end thereof and the biased means is
a spring member which is adjustably compressed by a threaded member
retained by the thread means of the pivot pin.
3. A swing arm assembly for holding a dressing device as in claim 2
in which the thread means of the pivot pin is a threaded aperture
and the threaded member is a headed screw carried therein.
4. A swing arm assembly for holding a dressing device as in claim 3
in which there is provided a set screw also carried in the other
end of the threaded aperture of the pivot pin, said set screw
disposed to be tightened to retain the headed screw in its adjusted
condition.
5. A swing arm assembly for holding a dressing device as in claim 2
in which the member against which the head of the pivot pin is
drawn is provided with an anti-friction bearing disposed to engage
the head of the pivot pin so that any relative motion of the member
and the pivot pin is made with said anti-friction bearing
interposed between the head and member.
6. A swing arm assembly for holding a dressing device as in claim 5
in which the anti-friction bearing engaging the pivot pin head is a
ball bearing having both radial and thrust capacity.
Description
CROSS REFERENCE TO A RELATED APPLICATION
The swing arm of this application is shown as a preferred dressing
tool holder used on and with a center-hole grinder as shown and
described in U.S. Pat. No. 3,548,545 which issued Dec. 22,
1970.
BACKGROUND OF THE INVENTION
1. Field of the Invention
With reference to the classification of art as established in the
U.S. Patent Office this invention pertains to the class entitled,
"Stone Working," and more particularly to the subclass therein
entitled "grinding wheel dressing."
2. Description of the Prior Art
Dressing devices for truing the face or faces of grinding wheels
usually require the movement of a dressing device such as a diamond
dresser across the face of a grinding wheel. In order that this
dressing device be maintained in a true predetermined plane
providing the desired facing action, the movement of the movable
arm must be precisely controlled. In the swing arm shown in the
preferred embodiment a spring-loaded pivot joint permits the
dressing device to be selectively moved in a precise and prescribed
arc around the pivot joint in a vibration dampened manner. An
example of a swinging arm device is seen in U.S. Pat. No. Re.
26,920 which issued June 23, 1970 to Parapetti. In this patent and
others showing like devices there is provided elaborate arm
construction disposed to provide movement control means which
attempt to prevent unwanted and excessive vibration of the dressing
medium when and as it is moved over the face of a grinding wheel to
effect dressing of said wheel to a determined faced condition. In
the dressing device shown in the Parapetti patent and in many
similar devices the arm construction is extremely elaborate and
expensive and often does not provide the dampening effect necessary
to provide a true dressing or shaping of the grinding wheel.
In the present invention there is provided a simple swing arm of
two-piece construction wherein a novel pivoted assembly provides a
simple joint of substantial strength and having a low friction. The
pivot joint additionally provides a selective dampening action
which is provided by an adjustably tightened cup-shaped spring
washer which permits the movable arm to be swung while being
restrained by a desired frictional restriction.
SUMMARY OF THE INVENTION
This invention may be summarized at least in part by reference to
its objects.
It is an object of this invention to provide, and it does provide,
a swing arm for holding a dressing device in which the arm has an
anti-friction pivot joint which also has an adjustable dampening
means to provide a desired restriction to the swing action of the
movable arm.
It is a further object of this invention to provide, and it does
provide, a swing arm for holding a dressing device wherein the
fixed arm is attachable in an adjustable manner to a portion of a
machine tool and in which the swinging arm portion is rotatably
carried by an anti-frictional pivot joint, said swing arm having a
threaded aperture at its outer end adapted to receive and
adjustably retain a dressing holder having a threaded outer
body.
The swing arm of this invention includes a support member which is
removably mounted to the machine tool. A swing member has its outer
end provided with a threaded aperture disposed to receive and
retain a grinding wheel dressing means such as a diamond dressing
point. The pivot joint between the support and swing member
provides an anti-friction arrangement in which a roller thrust
bearing is mounted between the members and sealed from grit and
dust by means of an O-ring. The head of the pivot pin is retained
by a ball bearing while the other end of the pivot pin and the
whole joint is maintained in a determined tensioned and frictional
restraint by a cup-shaped spring washer which is adjustably
tightened to provide the desired frictional resistance against
vibration and rotation.
In addition to the above summary the following disclosure is
detailed to insure adequacy and aid in understanding of the
invention. This disclosure, however, is not intended to prejudice
that purpose of a patent which is to cover each new inventive
concept therein no matter how it may later be disguised by
variations in form or additions of further improvements. For this
reason there has been chosen a specific embodiment of the swing arm
as adopted for use in grinding wheel dressing and showing a
preferred means for mounting the arm to the base or other fixed
portion of a machine tool.
This specific embodiment has been chosen for the purposes of
illustration and description as shown in the accompanying drawing
wherein:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 represents a sectional side view showing the preferred
construction and assembly of the swing arm of this invention;
FIG. 2 represents a plan view of the arm of FIG. 1, the view taken
on the line 2--2 of FIG. 1, and
FIG. 3 represents, in an enlarged sectional view, a fragmentary
portion of the roller thrust bearing and the means for mounting an
O-ring to provide the shielding for the thrust bearing necessary to
prevent the penetration of dirt, dust or other contaminants into
the rollers of the thrust bearing.
In the following description and in the claims various details will
be identified by specific names for convenience; these names,
however, are intended to be generic in their application.
Corresponding reference characters refer to like members throughout
the several figures of the drawing.
The drawing accompanying, and forming part of, this specification
discloses certain details of construction for the purpose of
explanation of the broader aspects of the invention, but it should
be understood that structural details may be modified in various
respects without departure from the concept and principles of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in particular to FIGS. 1 through 3, it is to be noted
that a fixed member 10 is formed with an elongated slot 12
extending longitudinally through a substantial portion of the
member. This slot is shouldered to receive and retain the head 14
of a socket head cap screw 16 seen in phantom outline in FIG. 1.
This arm 10 has its right end reduced in thickness to provide an
upper face portion 18 of a flat determined extent. In the middle of
this face portion and at right angles thereto is formed an aperture
20 of determined size which is disposed to receive the outer
diameter of the shank of a headed pivot pin 22.
A swinging arm member 30 is shown partly in section in FIG. 1 and
includes a threaded aperture 32 formed through the right or distal
end of the swing member 30. The left or pivoted end of this member
is reduced slightly in thickness to provide a flat and parallel
surface 34 adapted to support one of the race members of a roller
thrust bearing 38. This thrust bearing is of a conventional
construction and has two facing race members which are identified
as 40 and 42. These race members are usually hardened and ground
steel designed to support the thrust or load of a plurality of
rollers 44 in a customary manner. These rollers are shown as
carried in a cage 46 which is normally provided with a roller
thrust bearing. A rubber O-ring 50 is sized to seat in chamfered
shoulders 52 and 54 which are formed on the outer facing edges of
members 40 and 42 so as to provide a smooth retaining seat for the
O-ring when the bearing has been mounted in its usual rotating
condition. In its assembled condition as seen in FIG. 3, the O-RING
50 is in a slightly stretched condition when it is mounted in the
groove provided by angular shoulders 52 AND 54. The snug fit of the
O-ring provides a dust and dirt shield and at the same time it
provides a small degree of restriction to the relative movement of
race members 40 and 42 to one another.
The chamfered shoulders 52 and 54 are specially formed on members
40 and 42 so that in its assembled condition a determined groove is
provided. The groove shoulders are preferably quite smooth so that
the O-ring may slide on these surfaces without attrition of the
O-ring and to reduce the ability of dust, dirt and wet slurry to
enter the bearing.
Arm 30 has an aperture 60 formed therein which is sized to provide
a rotative guide and retention of the shank of pivot pin 22. A
shouldered recess 62 is formed on the underside of arm 30 and is
made concentric with aperture 60. This recess receives and retains
the outer race of a ball bearing 64. This bearing 64 is
contemplated to be a combination radial and thrust bearing of
conventional configuration. The inner race of the bearing 64
receives the shank of the pivot pin 22 and also accepts and retains
the thrust load exerted by the head of the pivot pin.
Pivot pin 22 is headed at one end which as seen in FIG. 1 is the
lower end. In the preferred embodiment, a threaded aperture 66 is
formed axially through pin 22 and may have 20 threads per inch for
receiving a one-quarter inch screw. A cup-spring washer 70 has a
determined outer diameter and an inner diameter whose aperture is
adapted to receive the head 72 of an oval-headed screw 74 and to
seat this head in the inner aperture of the washer 70. The threaded
shank of the screw 74 is mounted in and retained in the threaded
aperture 66 in the pivot shaft 22. A set screw 76 is shown as also
mounted in the threaded hole 66 and is accessible through the head
end of the pivot shaft 22 so as to be rotatably tightened to lock
the screw 74 in its adjusted position.
USE AND OPERATION OF THE SWING ARM
Preferably member 10 is brought to a support member 80 as seen in
phantom outline in FIG. 1. This support member is provided with a
taped or threaded hole 82 adapted to receive the threaded end of
cap screw 16. The member 10 when screw 16 is tightened is brought
into a determined clamped or retained relationship with body 80. A
wedge member 84 may be mounted in a groove and hole in member 80,
or any other suitable type of adjusting support block or wedge
member may be provided so that member 10 may be slid back and forth
and tilted to provide a desired angular relationship of member 10
to the block. This also determines the angular relationship of
threaded hole 32 to the face of the grinding wheel to be dressed.
This grinding wheel being of any conventional configuration and
mounting has not been shown. With member 10 in a locked condition
in a desirable angle to and on the body member 80, the arm 30 may
be now moved around the pivot pin 22 by manipulation of the outer
end of the arm 30. The screw 72 is rotated in or out to provide a
determined tension or load on the thrust bearing 38 and the ball
bearing 64. The tension or load is increased in response to the
degree of flatening of the cup-shaped washer 70. A grinding wheel
dressing device is contemplated as being carried by a threaded
shank 86 shown in phantom outline in FIG. 1. The dressing device is
adjusted as it is rotated in or out in the threaded aperture 32 and
is moved forwardly or backwardly the amount necessary or desired to
bring the dressing end of the member in way of the face of the
grinding wheel to be dressed.
The roller bearing 38 provides a smooth anti-friction support of
member 30 by member 10. The bearing 64 insures that the member 30
as it is rotated around the head of the pinion member 22 moves with
an equal amount of restraint. As the thrust load developed by the
tightening of spring 70 places a like load upon the bearing 64 it
is desirable that the bearing 64 be a ball bearing having
properties adapted to accept and maintain at all angles or rotation
the determined amount of thrust provided by the spring 70. The
screw 72 is adjusted to provide the desired degree of bias or load
on the bearings 38 and 64 so that as the arm 30 is moved to a
determined dressing position it will stay at this position while
the dressing device carried by shank 86 is rotated forward and back
to the desired dressing condition whereupon the arm 30 is swung in
an arc to dress the face of the grinding wheel in the desired
manner.
The swing arm of this invention provides a simple means of
providing an anti-friction joint having a high thrust capacity as
provided by means of a pre-loaded roller thrust bearing. The
rollers and facing raceway of this bearing are protected from
contamination by grit and dust by means of an O-ring snugly mounted
in the groove provided by the chamfered shoulders 52 and 54 formed
in the facing outer edges 40 and 42 of the bearing 38. The spring
70 provides a dampening effect to the arm to reduce if not
eliminate the vibrations which develop during the movement of the
dressing device over the face of the grinding wheel. The O-ring
when its stretched condition also acts as a partial dampener as
well as providing a drag or brake to the rotative movement of arm
30 around the pivot pin 22.
Whether the member 10 is mounted on a base or a column of a machine
tool it is desirable that the arm be rigidly attached to permit
only a minimum vibration. Adjustment for the angle of dress of the
face of the grinding wheel is provided by changing the angle of
mounting of member 10. Whether by means of a wedge member 82 or by
some other angle support, the arm in its retained condition is
mounted so that the axis of the pivot pin is at right angles to the
line of dress of the grinding wheel. The dressing device may be
either a diamond, a carborundum (TM, The Carborundum Company,
Niagara Falls, New York) stick or other dressing means carried in a
holder which is adjustably carried in arm 30 so as to be precisely
moved to the desired dressing condition.
It is to be noted that for the cup-shaped spring 70 a resilient
member such as a rubber washer may be used. A flat metal washer
under the head of the screw of course would be used to transmit the
effective compressive force to the rubber washer. Instead of a
roller bearing 64 other bearings such as porous bronze could be
used. Instead of screw 74 in threaded aperture 66 the pivot pin 22
may have an exterior threaded end and a nut mounted thereon. The
bearing 64 could be mounted in arm 10 and pivot pin 22 reversed in
its mounted arrangement with washer 70 and screw 74 disposed on the
bottom of the assembly of FIG. 1.
Terms such as "left," "right," "up," "down," "bottom," "top,"
"front," "back," "in," "out" and the like are applicable to the
embodiment shown and described in conjunction with the drawing.
These terms as used are merely for the purpose of description and
do not necessarily apply to the position in which the swing arm may
be constructed or used.
While a particular embodiment of the swing arm has been shown and
described it is to be understood the invention is not limited
thereto and protection is sought to the broadest extent the prior
art allows.
* * * * *