U.S. patent number 3,643,385 [Application Number 04/877,987] was granted by the patent office on 1972-02-22 for portable grinding tool.
Invention is credited to Toshio Mikiya.
United States Patent |
3,643,385 |
Mikiya |
February 22, 1972 |
PORTABLE GRINDING TOOL
Abstract
A portable grinding tool consisting of a handle, a telescopic
holder and arm having a rotatable pulley attached to one end. The
telescopic holder is adjustably fastened to the handle at variable
angles, and a rotatable driving member positioned within the holder
is adapted to be driven by suitable power means so as to rotate a
grinding belt entrained about and interconnecting the driving
member and the rotatable pulley. Pressure plates for the belt and
pulleys of various configurations may be interchangeably mounted
for the effective and accurate grinding of different surfaces of a
wide range of objects.
Inventors: |
Mikiya; Toshio (Ota-ku, Tokyo,
JA) |
Family
ID: |
26403792 |
Appl.
No.: |
04/877,987 |
Filed: |
November 19, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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729692 |
May 16, 1968 |
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Foreign Application Priority Data
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Sep 30, 1967 [JA] |
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42/62742 |
Dec 27, 1967 [JA] |
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42/83308 |
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Current U.S.
Class: |
451/355 |
Current CPC
Class: |
B24B
23/06 (20130101) |
Current International
Class: |
B24B
23/06 (20060101); B24B 23/00 (20060101); B24b
023/00 () |
Field of
Search: |
;51/170.4,141,135 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Jones, Jr.; James L.
Parent Case Text
This is a continuation-in-part of application Ser. No. 729,692
filed May 16, 1968.
Claims
What is claimed is:
1. A portable grinding tool comprising;
handle means;
a holder having a bore therein, said holder including a clamping
ring for adjustably fastening said holder to said handle means, a
slot extending through said clamping ring, and adjusting means
interconnecting the ends of said clamping ring adjacent said slot
for alternatively loosening and tightening said clamping ring ends
together, such that the angular relationship between said holder
and said handle means is adjustable;
a projecting arm member positioned within said bore and having one
end extending from said holder;
driving wheel means rotatably mounted on said holder and adapted to
be driven by suitable driving means;
a pulley rotatably mounted on the projecting end portion of said
arm member; and
an endless grinding belt interconnectingly encompassing said
driving wheel means and said pulley for rotation therewith.
2. A grinding tool as defined in claim 1 wherein said clamping ring
includes clamping seats located on both sides of said slot, and
wherein said adjusting means interconnects said clamping seats for
loosening and tightening said clamping ring.
3. A grinding tool as defined in claim 1 wherein said handle means
includes a portion extending into said clamping ring.
4. A grinding tool as defined in claim 1 wherein said handle means
includes a housing containing drive means therein, said housing
being adjustably fastened to said holder.
5. A grinding tool as defined in claim 1 including cooperating ball
and detent means in said holder adapted to determine the relative
angular position between said holder and said handle means.
6. A grinding tool as defined in claim 5 wherein said handle means
includes detents formed therein and wherein said holder includes
spring-biased ball means therein which cooperate with said
detents.
7. A grinding tool as defined in claim 1 including a pulley support
means adjustably coupled to the free end of said projecting arm,
said pulley being rotatably mounted on said pulley support
means.
8. A grinding tool as defined in claim 7 wherein said pulley
support means includes a bore therein adapted to receive the free
end of said projecting arm, the diameter of said bore being larger
than the outer diameter of said projecting arm.
9. A grinding tool as defined in claim 8 wherein said pulley
support means includes a pin adapted to pass through holes in said
pulley support means and through a hole in the free end of said
projecting arm.
10. A grinding tool as defined in claim 9 further comprising a pair
of setscrews threadably inserted in the walls of said pulley
support means for fixedly securing said pulley support means to the
free end of said projecting arm member.
11. A grinding tool as defined in claim 10 wherein said projecting
arm and said pulley support means are movable with respect to each
other along the longitudinal axis of said pin, said setscrews
fixedly securing said projecting arm and said support means
relative to each other at a predetermined point along the
longitudinal axis of said pin.
12. A grinding tool as defined in claim 11 wherein said projecting
arm and said pulley support means are movable with respect to each
other about the longitudinal axis of said pin, said setscrews
fixedly securing said projecting arm and said support means at a
predetermined relative position.
13. A grinding tool as defined in claim 1 including pressure plate
means fastened to said holder, said pressure plate means being
adapted to contact portions of said grinding belt to support said
belt.
14. A grinding tool as defined in claim 13 wherein said pressure
plate means comprise contact shoe surface means engaging the inner
surface of portions of the grinding belt run between said driving
wheel means and said pulley.
15. A grinding tool as defined in claim 13 wherein said pressure
plate means are removably mounted on said holder.
16. A grinding tool as defined in claim 15 including a projection
on said pressure plate means, complementary recess means on said
holder adapted to receive said projection, and fastener means
projecting through aligned apertures in said projection and holder
recess means for mounting said pressure plate means on said
holder.
17. A grinding tool as defined in claim 1 including a generally
L-shaped bracket means fastened to the free end of said projecting
arm member, cantilever shaft means projecting from said bracket
means, and said pulley being rotatably mounted on said shaft
means.
18. A grinding tool as defined in claim 17 wherein said pulley is
detachably mounted on said shaft means so as to be interchangeable
with other pulleys.
19. A grinding tool as defined in claim 1 wherein said pulley is
detachably mounted on said projecting arm end portion so as to be
interchangeable with other pulleys.
20. A portable grinding tool comprising:
handle means;
a holder attached to one end of said handle means, said holder
having a bore therein;
a projecting arm member positioned within said bore and having one
end extending from said holder;
driving wheel means rotatably mounted on said holder and adapted to
be driven by suitable power means;
a pulley support means adjustably coupled to the free end of said
projecting arm, said pulley support means including a bore therein
adapted to receive the free end of said projecting arm, the
diameter of said bore being larger than the outer diameter of said
projecting arm;
a pulley rotatably mounted on said pulley support means; and
an endless grinding belt interconnectingly encompassing said
driving wheel means and said pulley for rotation therewith.
21. A grinding tool as defined in claim 20 wherein said pulley
support means includes a pin adapted to pass through holes in said
pulley support means and through a hole in the free end of said
projecting arm.
22. A grinding tool as defined in claim 21 further comprising a
pair of setscrews threadably inserted in the walls of said pulley
support means for fixedly securing said pulley support means to the
free end of said projecting arm member.
23. A grinding tool as defined in claim 22 wherein said projecting
arm and said pulley support means are movable with respect to each
other along the longitudinal axis of said pin, said setscrews
fixedly securing said projecting arm and said support means
relative to each other at a predetermined point along the
longitudinal axis of said pin.
24. A grinding tool as defined in claim 23 wherein said projecting
arm and said pulley support means are movable with respect to each
other about the longitudinal axis of said pin, said setscrews
fixedly securing said projecting arm and said support means at a
predetermined relative position.
Description
This invention relates to grinding tools and, in particular,
relates to improvements in portable grinding tools having
adjustable handles adapted to permit grinding operations on various
objects and surfaces under different working conditions.
In the prior art many types of grinding tools have been and are
being currently utilized. Under certain operating conditions, it
may be particularly desirable to utilize an endless, continuously
driven grinding belt. However, prior art grinding tools which
include such grinding belts require relatively large, heavy and
cumbersome devices for the mounting and driving of the belts,
thereby rendering manual handling and operation difficult.
Moreover, since grinding belts generally have flat grinding
surfaces and unless the objects to be ground also have flat
surfaces, no unique and desirable grinding effect has been
heretofore obtainable. Grinding corners or grooves with prior art
grinding belt devices or tools has been practically impossible, and
even when efficiently operated were vastly inferior to manual
grinding and limited in their applications.
The present invention provides for an improved grinding tool which
obviates and eliminates the disadvantages and drawbacks of prior
art grinding tools. An important aspect of the present invention
lies in providing a portable grinding tool which can be simply and
efficiently manipulated by means of a single-handed operation while
attaining an accurate degree of grinding proficiency. To this
purpose the present invention contemplates the provision of a
relatively simple portable grinding tool comprising essentially a
grip or handle, a holder and arm having a rotatable belt pulley,
with said holder including a rotatable driving member adapted to be
driven by a suitable power source, and including an endless
grinding belt entrained about and interconnecting said driving
member and belt pulley. The grinding belt extends from the handle
by means of the holder and arm and is driven in order to provide
the same type of smooth grinding operation as in the case of other
types of grinding tools. The arm is attached to the holder so as to
facilitate relative telescopic motion, and includes elastic
material, such as springs, which will impart predetermined and
constant operating tension to the grinding belt.
Another feature of this invention is to provide a portable grinding
tool with an adjustably mounted grinding belt relative to the grip
or handle. The portable grinding tool according to this invention
is provided with a grinding belt mounted as described above whereby
variation of the mounting angle of the grinding belt relative to
the handle facilitates different grinding attitudes irrespective of
the type of surface to be ground or of the physical position of the
operator.
Another important aspect of this invention is to eliminate
excessive deflection of the grinding belt during operation so as to
allow accurate grinding of flat work surfaces and the like. For
this purpose, the portable grinding tool mounts a pressure plate
adjacent to the inner surface of the rotating grinding belt. A
deflected belt may be occasionally effective, when grinding, for
example, curved or arcuate surfaces, because the belt will contour
itself to such work surfaces. However, the deflectable belt, even
when tensioned, will not effectively provide the desired grinding
action when applied to a flat surface, because the unsupported belt
portion will deflect and lose contact with the grinding surface.
Mounting a pressure plate adjacent to the under surface of the
grinding belt will provide effective grinding pressure against the
flat surface of an object to be ground by the grinding belt,
thereby greatly enhancing the versatility of the present inventive
grinding tool.
It is also preferable that the pressure plate be mounted on the
grinding tool so as to be easily removable. As may be evident from
the above description, mounting of the pressure plate on the
grinding tool may be useful in one phase of the grinding operation
but not so in another. Consequently, mounting, removal and
replacement of the pressure plate is quite desirable from the
standpoint of increasing the applicable range of the present
grinding tool. The pressure plate, according to this invention, can
be readily removed and mounted by a relatively unskilled operator
without difficulty.
A preferred embodiment of this invention contemplates a portable
grinding tool capable of accurately grinding surfaces and contours,
such as corners and grooves. In this embodiment, the grinding belt
pulley is mounted to the extreme end of the arm by means of an
L-shaped support so as to eliminate any obstacles or restrictions
on one side of the grinding belt. Accordingly, the belt may be
maneuvered into corners and grooves of articles to be ground, to
provide a high degree of accuracy in grinding and obviate the need
for manual after-finishing of the articles. The belt pulley can be
interchanged with various other belt pulleys of differently
contoured shapes or surfaces in order to vary the contacting
surface of the grinding belt in conformance with the irregular or
contoured surfaces of objects to be ground.
Accordingly, it is a primary object of the present invention to
provide an improved and novel portable grinding tool.
Another object of the present invention is to provide a grinding
tool as herein described which includes a novel grinding belt
construction whereby the tool may be used to grind surfaces of
various configurations.
A further object of the present invention is to provide a portable
belt-type grinding tool as herein described whereby the angular
relationship between the grinding belt and tool handle may be
adjusted and varied so as to increase the versatility of the
grinding tool.
A still further object of the present invention is to provide a
grinding tool as herein described including removable pressure
plate means which may be mounted adjacent to the inner surface of
the grinding belt when grinding flat work surfaces and which may be
removed to allow deflection of the grinding belt when grinding
contoured work surfaces.
Yet another object of the present invention is to provide a
portable grinding tool as herein described including
interchangeable and removable belt pulleys about which the grinding
belt is entrained and whereby the grinding tool may be adapted to
grind corners and grooves of work surfaces at high degrees of
accuracy.
For a better understanding of the present invention, reference may
now be had to the following detailed description and accompanying
drawings, in which:
FIG. 1 is a side view illustrating one embodiment of a portable
grinding tool according to this invention;
FIG. 2 is a plan view, partially in section, of the grinding tool,
as shown along line 2--2 in FIG. 1;
FIG. 3 is a plan view, partially in section, of a second embodiment
of a portable grinding tool according to this invention;
FIG. 4 is a side view of the embodiment of FIG. 3;
FIGS. 5a through 5c illustrate various illustrative embodiments of
pressure plates used in connection with the present grinding tool,
as shown in the fragmentary section along line 5--5 in FIG. 4;
FIG. 6 is a cross section shown along line 6--6 in FIG. 5a;
FIG. 7 is a sectional plan view, illustrating one embodiment of a
grinding belt pulley as shown within the circled portion 7--7 in
FIG. 3; and
FIGS. 8a through 8c are illustrative of various embodiments of
grinding belt pulleys used in the grinding tool of the present
invention.
Referring now to the drawings, FIGS. 1 and 2 illustrate one
embodiment of the grinding tool of this invention, showing a hollow
bearing support housing 1 formed at one end of a handle or grip 2.
A motor or other rotatable power source 3 may be inserted within
said bearing support housing 1, while two shafts 4a, 4b project
from the opposite ends of a rotating member 5 forming part of the
motor 3. Shaft 4a is rotatably supported by a bearing 6 positioned
within bearing housing 1, and shaft 4b is rotatably supported by a
bearing 7 located within a retaining ring 8 located at the opening
of the bearing support housing 1. A rotatable driving wheel 9 is
fastened to the shaft 4b projecting from the housing opening by
means of a suitable key and keyway. A clamping holder 11 is
positioned over the support housing 1 adjacent to the opening. The
holder 11 includes a slot 11a at one end thereof, having a pair of
clamping members 10a, 10b on both sides of the holder 11, thereby
forming a clamping ring member 11a whereby a clamping means 11b,
such as a screw or bolt, may allow suitable fixed or variable
movement of the holder 11 and handle 2. Holder 11 includes a shaft
support extension 12 on one side adapted to receive the end of
shaft 4b so as to rotatably guide driving wheel 9. A hollow tube
member 13 having a central bore 14 is positioned in support
extension 12 by means of a threaded surface 14a. A tubular arm 15
extends from bore 14 and includes an internal tension spring 16.
Tube member 13 includes an elongated slot 17 having generally
semicircular ends. One end of arm 15 includes a supporting base
portion 19 attached firmly thereto, whereas the other end of said
arm 15 extends into the central bore 14 in tube member 13. A
projecting means 18 extends from the side of tubular arm 15 and
projects through elongate slot 17. The supporting base portion 19
is a clevis adapted to rotatably mount a pulley 20 and a mobile
wheel between the arms of the clevis. An endless resilient grinding
belt 21 is mounted on and entrained to rotate about driving wheel 9
and belt pulley 20. The center portion of tube member 13 supports,
in fixed relationship, a pressure plate 22 including pressure shoes
22a which are applied to the inner surface of said grinding belt
21. A number of suitably spaced detents 23 are arranged on the
outer surface of bearing support housing 1. A ball 25 positioned in
a bore 24 in holder 11 is adapted to contact detents 23 under the
urging of a resilient tension spring 26 located in the bore 24. A
hole 27 extends through handle 2 along its length, and at the free
end of the handle 2 connects to a fitting joint 28. By means of
joint 28 and through hole 27 compressed air or electric current
(depending on the type of motive power) is supplied to power source
3. When using compressed air, a control port 29 in handle 2, and
connected to hole 27, may be utilized to control the amount of
compressed air flowing to power source 3.
From the foregoing description it becomes evident that supplying
compressed air and the like to power source 3 through hole 27 will
impart rotation to rotating member or impeller 5 and
correspondingly rotate driving wheel 9 by means of shafts 4a and
4b. In this manner, the grinding operation of the tool is attained
through the resulting rotation of grinding belt 21 over the driving
wheel 9 and belt pulley 20. In this embodiment, the pulley 20 is
mounted to the end of arm 15 which is constantly being outwardly
extended under the tension exerted by elastic spring member 16,
thereby imparting the required tension to the grinding belt 21 and
effectively transmitting the driving power of said driving wheel 9,
whereby smooth and constant rotation of the grinding belt 21 is
obtained. The projecting means 18 in slot 17 limits the outward
motion of arm 15. Pressure shoes 22a of pressure plate 22 will
guide the movement of grinding belt 21, whereby along with the
tensioning of the grinding belt 21, the latter is effectively
maintained against the surface to be ground during grinding and to
thereby obtain accurate grinding. Through loosening clamping means
11b holding clamping members 10a and 10b, the angle of handle 2
relative to arm 15 and to holder 11 may be adjusted and varied
optionally as shown in FIG. 1 through the dotted lines, whereby
grinding belt 21 may be positioned at variable angles with respect
to handle 2. This will facilitate the grinding of articles
positioned at various degrees of inclination without undue
difficulties.
A second embodiment of the invention is illustrated in FIGS. 3 to 6
of the accompanying drawings. This embodiment is generally similar
to the one illustrated in FIGS. 1 and 2, but differs in the
construction of certain of the grinding tool components. All
components not designated by reference numerals may be assumed to
be identical to those in the first described grinding tool
embodiment. In the embodiment shown in 4b, 3-6, the compressed air
is controlled by a control port 40 attached to the side of handle
2, and control of the compressed air to the power source is
achieved by means of a valve 41 constituting the shaft 42 of an
actuating member 43. (FIG. 4) Bearing support housing 1 is equipped
with a cover 44 in lieu of an opening as shown in FIGS. 1 and 2,
and a supporting ring 45 including bearing 6 is fastened to lid 44.
Driving wheel 9 has a drum-shaped, hollow center and is fastened to
the end of shaft 4b, the latter of which is cantilevered without
shaft support extension 12 as in the case of FIGS. 1 and 2. A
clamping nut 46 at the end of shaft 4b is inserted within a recess
47 formed on the side of driving wheel 9 so as not to project
outwardly thereof. Holder 11 and arm guide 13 shown in FIGS. 1 and
2 are integrally formed in this embodiment, so in effect arm guide
13 projects from one side of a holder 11. Pressure plate 22 having
pressure shoe 22a in FIGS. 1 and 2 is fastened to the center
portion of arm guide 13 with its cylindrically shaped base, however
in this embodiment a pair of supporting bases 48, 48a are
positioned on either side of the bottom of arm guide 13 in FIG. 5.
A projection 49 formed at the base of pressure plate 22 is inserted
between the supporting bases or forks 48, 48a and a mounting rod or
shaft 50 extending through supporting bases 48, 48a is inserted
through the projection 49, said projection being narrow at one end
and adapted to be inserted over said shaft 50 with a gradually
opening end portion.
In mounting the pressure plate 22 as shown in FIGS. 3-6, projection
49 of plate 22 is moved toward arm guide 13 and by manipulation
toward shaft 50 (FIG. 6), may be readily mounted on the grinding
tool. While grinding belt 21 is rotating, a frictional working
force is generated through friction toward said pressure plate 22
in the direction of the arrow shown in FIG. 6, tending to maintain
the pressure plate 22 in mounted position. Removal of the pressure
plate 22 is easily accomplished by manipulating it in opposition to
the direction of the arrow in FIG. 6 while the driving belt 22 is
stationary. Accordingly, the pressure plate 22 may be alternatively
mounted or removed depending on whether flat surfaces or curved
surfaces are to be ground.
FIGS. 5A, 5B, and 5C of the drawings illustrate various embodiments
of pressure plate 22. FIG. 7 illustrates the mounting construction
for belt pulley 20 for the second tool embodiment. In the
embodiment shown in FIGS. 1 and 2, belt pulley 20 is supported by
I-shaped supporting clevis 19 at the end of arm 15. Although use of
such an I-shaped supporting clevis 19 will provide adequate support
for the belt pulley 20, the supporting clevis 19 projecting along
the sides of the belt 21 will prevent the effective grinding of
corner surfaces of articles. In this second embodiment, an L-shaped
supporting bracket 51 is attached to the end of arm 15, whereby a
cantilevered shaft 52 mounted on the supporting bracket 51,
rotatably supports grinding belt pulley 20. Thus, the other side of
grinding belt 21 is free to be inserted into corners and grooves of
articles for this type of accurate grinding. In attaching shaft 52
to the supporting bracket 51, belt pulley 20 is mounted on the
shaft 52 with a flange 53 on one end, and shaft 52 is inserted
through a shaft bore 54, and retained by clamping means 55. By
loosening said clamping means 55, the shaft 52 may be pulled out
from the support bracket 51, so as to interchange belt pulleys 20.
The belt pulley 20 may be exchanged from flat surfaced ones as
shown in FIGS. 1 and 2, or FIGS. 3 and 4, for one with V-shaped
concave surface as in FIG. 7 or for one with an arc-shaped convex
surface 57 as shown in FIG. 8A, V-shaped convex surface 58 as shown
in FIG. 8B, and for arc-shaped concave surface 59 as shown in FIG.
8C. Thus, belt pulleys 20 having different contoured surfaces will
provide varied contours to the grinding surfaces of grinding belt
21, thereby effectively contouring the rotatable belt pulley 20 in
accordance with the surface configurations of objects to be ground,
and in particular in relation to cases where uneven surfaces such
as corners and grooves are to be ground.
Referring to FIGS. 9 and 10, there is shown a modification of the
present invention whereby a pulley support device is removably and
adjustably connected to the end of arm 15. Corresponding elements
in FIGS. 9-12 are given the same reference numeral designations.
The pulley support device includes an adjustment member 60 which
has a bore 68 therein which is adapted to fit over the end of the
arm 15. The bore 68 in adjustment member 60 is of a larger diameter
than that of the end of arm 15, and in this embodiment is tapered
out toward the opening of bore 68. Protruding from adjustment
member 60 is a support arm 61 to which the pulleys 62 are rotatably
secured. In the embodiment shown the support arm 61 carries two
shafts (or protrusions) 64. On each shaft 64 is mounted a ball
bearing 63 on which the pulleys 62 are rotatably mounted. Pulleys
62 may be press fit over ball bearings 63 or secured thereto by
means of a setscrew, or the like. Equivalent alternative mounting
methods for pulleys 62 should be apparent to those skilled in the
art.
The adjustment member 60 is mounted over the end of arm 15 and a
pin 65 (see FIGS. 9 and 12) is inserted through a hole 69 in arm 15
and through mating holes 70 in adjustment member 60. After the pin
65 is inserted and the position of member 60 is set, two screws 66
and 67, which are threadably mounted in member 60, are tightened to
fixedly locate the adjustment member 60 with respect to the end of
arm 15. In this manner, as seen most clearly in FIGS. 10 and 12,
the alignment of the arm 15 along the longitudinal axis of pin 65
with respect to adjustment member 60 can be adjusted in order to
insure that the pulleys 62 are properly aligned with the drive
pulley 3 (shown in FIG. 1, for example). Preferably the rotating
axis of the drive pulley 3 and of pulleys 62 are adjusted to be in
parallel. Pin 65 acts as a pivot member or fulcrum about which
adjustment member 60 is movable relative to arm 15.
When the apparatus is adjusted, adjustment member 60 is supported
firmly at three points; at the end of the two setscrews 66 and 67,
and at the inner wall of the adjustment member 60. It is possible
to maintain stable operation by means of this configuration in
spite of the vibrations which occur at high operating speeds. Also,
by virtue of the adjustment mechanism, it is possible to prevent
the grinding belt from dropping off the main wheel and the pulley,
thereby facilitating the operation of the grinding apparatus.
Another feature of the embodiment shown in FIGS. 9-12 is that there
are no protruding members (such as members 51 and 55 of FIG. 7) on
the outside edges of the pulleys 62. By means of this embodiment,
the grinding apparatus may be more easily utilized to grind narrow
crevices, deep grooves and corners.
By virtue of the fact that alignment of the supporting member 60
with respect to the arm 15 can be facilitated, strains in the
grinding belt can be more efficiently absorbed and it is possible
to keep the grinding belt properly in place over the pulleys 62
even when the belt is being run at high speeds. Also, by adjusting
the alignment between supporting member 60 and arm 15, it is
possible to prevent the pulley from falling off due to excess warp
in the endless grinding belt or due to the rotating axis of the
drive wheel and the rotating axis of the pulley not being parallel.
Thus, the adjustment device shown in FIGS. 9-12 enables more
precise alignment and adjustment of the grinding apparatus to
compensate for the various imperfections and variations in
apparatus which may arise.
* * * * *