U.S. patent number 3,690,728 [Application Number 05/070,340] was granted by the patent office on 1972-09-12 for resilient retaining means for joining work tools and work tool holders.
This patent grant is currently assigned to The Cincinnati Mine Machinery Co.. Invention is credited to Claude B. Krekeler.
United States Patent |
3,690,728 |
Krekeler |
September 12, 1972 |
RESILIENT RETAINING MEANS FOR JOINING WORK TOOLS AND WORK TOOL
HOLDERS
Abstract
Resilient retaining means for securing work tools either
rotatable or non-rotatable, in appropriate work tools holders or
mounting means. The work tools and holders are intended primarily
for use on mining, excavating and earth working machines and the
like. The work tools comprise elongated elements having a shank
portion with a working tip at one end and a gauge-determining
abutment surface at at least the other end. The holders or mounting
means comprise bodies having a shank receiving perforation and
means in association with the bottom of the perforation having an
abutment surface adapted to cooperate with the abutment surface on
the work tool. Either the work tool or the holder, and in a few
cases, both, is provided with a recess to receive a resilient
retaining means, usually, in the present invention, a special form
of spring clip, to frictionally retain the work tool in the holder
against longitudinal movement. In some cases the spring clip will
be captive in the holder and will frictionally engage the work tool
shank portion in such manner that the work tool will be
non-rotatable in the shank receiving portion of the holder. In
other cases the spring clip will also be captive in the holder and
will also frictionally engage the shank but both the shank and
retainer will rotate together with respect to the perforation. And
in still other cases the spring clip will be captive on the shank,
in a particular manner, and will frictionally engage the lug, the
work tool usually being rotatable within the clip and perforation.
Some of the clips may be arranged to either permit or prevent
rotation of the work tool in the perforation. Various
configurations and characteristics will be given these clips, such
as special shapes, surfaces and twists.
Inventors: |
Krekeler; Claude B.
(Cincinnati, OH) |
Assignee: |
The Cincinnati Mine Machinery
Co. (Cincinnati, OH)
|
Family
ID: |
22094694 |
Appl.
No.: |
05/070,340 |
Filed: |
September 8, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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842791 |
Jun 30, 1969 |
3622206 |
|
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753398 |
Aug 19, 1968 |
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Current U.S.
Class: |
299/109;
37/459 |
Current CPC
Class: |
E21C
35/197 (20130101); E21C 35/19 (20130101) |
Current International
Class: |
E21C
35/197 (20060101); E21C 35/19 (20060101); E21C
35/00 (20060101); E21c 025/46 () |
Field of
Search: |
;299/86,93 ;37/142A
;85/8.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Purser; Ernest R.
Parent Case Text
CROSS REFERENCE TO RELATED INVENTION
This is a continuation-in-part of the copending application of the
same inventor, Ser. No. 842,791 filed June 30, 1969 and entitled
CUTTER BITS AND MEANS FOR MOUNTING THEM now U.S. Pat. No.
3,622,206, said application Ser. No. 842,791 is a
continuation-in-part of the application of the same inventor,
Serial No. 753,398 filed Aug. 19, 1968 and entitled CUTTER BITS AND
MEANS FOR MOUNTING THEM, now abandoned.
Claims
Having thus described the invention, what is claimed as new and
what is desired to be protected by Letters Patent is:
1. A non-rotatable cutter bit and mounting means therefor for a
mining machine and the like, said cutter bit comprising an
elongated shank, at least one end of said shank terminating in a
bit abutment surface lying at an angle to the axis of said shank,
at least the other end of said shank having a cutting tip, said
mounting means comprising a lug having a body with a shank
receiving perforation, a lug abutment in association with said
perforation and comprising at least one lug abutment surface lying
at an angle to the axis of said perforation, said cutter bit shank
located within said shank receiving perforation, said bit abutment
surface and said lug abutment surface lying parallel to each other
and in abutting relationship, and means for retaining said cutter
bit in said shank receiving perforation, said cutter bit shank and
said shank receiving perforation being of non-circular cross
section, said shank receiving perforation having a groove therein,
said retaining means comprising at least one member of non-circular
configuration substantially surrounding said shank and having
outside dimensions larger than the cross sectional dimensions of
said perforation and smaller than the dimensions of said groove,
said retaining means having inside dimensions smaller than the
cross sectional dimensions of said cutter bit shank, said retaining
means adapted to be within said groove and frictionally engage said
shank at at least two points.
2. The structure claimed in claim 1 wherein said retaining means
comprises at least one non-circular, substantially C-shaped element
having spaced ends.
3. The structure claimed in claim 1 wherein said retaining means
comprises a single piece of coiled resilient wire having at least
one complete non-circular convolution.
4. The combination of a cutter bit and a mounting means therefor,
for use in mining, excavating and earth working machines and the
like, said cutter bit having a shank of non-circular cross section
and said mounting means having a perforation to just nicely receive
said shank, said mounting means having a recess therein adjacent
said perforation, and non-circular resilient retaining means
located in said recess and adapted to substantially surround and
receive said shank, the inner dimension of said resilient retaining
means being normally smaller than the outer dimension of said shank
and the outer dimension of said resilient retaining means being
greater than the outer dimension of said shank, whereby said
resilient retaining means frictionally engages said shank at at
least two points and remains engaged in said recess when said shank
is received in said perforation.
5. A retaining means for maintaining a work tool shank of
non-circular cross section within a work tool holder perforation of
non-circular cross section which comprises a resilient member
formed into a non-circular configuration to substantially surround
said shank and adapted to be received within at least one groove
located in at least one of said work tool and said work tool
holder, the outside dimension of said resilient member being
greater than the outside dimension of said shank and also greater
than the inside dimension of said perforation, and the inside
dimension of said resilient member is less than the outside
dimension of said shank, whereby, regardless of whether the groove
is on the shank or within the wall defining the perforation, said
resilient member will frictionally engage said work tool with said
work tool holder.
6. The retaining means of claim 5 in which said groove is in the
wall defining said perforation and said resilient member comprises
at least one non-circular, substantially C-shaped element having an
outside dimension slightly less than the outside dimension of the
said groove.
7. The retaining means of claim 6 in which said C-shaped element is
provided with a roughened surface on that portion which engages
said shank.
8. The retaining means of claim 5 in which said groove is in the
wall defining the said perforation and said resilient member
comprises a single piece of coiled wire and the like having at
least one non-circular convolution with an outside dimension
slightly less than the outside dimension of said groove.
9. The retaining means of claim 8 in which said single piece of
coiled wire and the like has at least two non-circular
convolutions.
10. The retaining means of claim 5 in which said groove is in the
wall defining said perforation, said perforation being non-circular
in cross section, and said resilient member comprises an open
ended, non-circular, ring-like structure having an outside
dimension slightly less than the outside dimension of said
groove.
11. The retaining means of claim 10 in which said resilient member
comprises a closed non-circular ring-like structure having more
than one convolution.
12. The retaining means of claim 5 in which said resilient member
forms a part of a non-circular helix, one end of said resilient
member being in a different horizontal plane than is the other end,
whereby one end of said resilient member will bear against one edge
of said groove and the other end of said resilient member will bear
against the opposite edge of said groove.
13. The retaining means of claim 12 in which said resilient member
is provided with a roughened surface on that part thereof which
engages said shank.
14. The retaining means of claim 5 in which said groove is in said
shank, said resilient member forming a part of a helix, one end of
said resilient member being in a different horizontal plane than is
the other end, whereby one end of said resilient member will bear
against one edge of said groove and the other end of said resilient
member will bear against the opposite edge of said groove.
15. The retaining means of claim 5 in which said resilient member
is arranged to be received in a said groove provided in said work
tool holder, the said inside dimension of said resilient member
having a rough surface to frictionally engage a said work tool.
16. The retaining means of claim 5 in which said resilient member
is arranged to be received in a said groove provided in said work
tool holder, the said inside dimension of said resilient member
having a protrusion adapted to be received in a groove provided on
said work tool.
17. The structure claimed in claim 5 wherein said shank and said
perforation have a rectangular cross section, said retaining means
having a cooperating substantially rectangular configuration.
18. The structure claimed in claim 5 wherein said shank and said
shank receiving perforation have a diamond-shaped cross section,
said retaining means having a cooperating substantially
diamond-shaped configuration.
19. In mining, excavating and earthworking machines and the like
having a work tool with a shank of non-circular cross section and a
work tool holder having a perforation to just nicely receive said
shank, improved means for holding said shank within said
perforation in said work tool holder, said improved means
comprising a groove in said work tool holder adjacent to and
communicating with said perforation, and a resilient retaining
means within said groove, said retaining means being formed into a
non-circular configuration to substantially surround said shank,
said retaining means having outside dimension larger than the cross
sectional dimensions of said perforation and smaller than the
dimensions of said groove, said retaining means having inside
dimensions smaller than the cross sectional dimensions of said
shank, whereby when said shank is received in said perforation said
shank is frictionally engaged by said retaining means at at least
two points and thereby retained in said perforation.
20. The structure claimed in claim 19 wherein said retaining means
comprises a non-circular, substantially C-shaped element.
21. The structure claimed in claim 19 wherein said retaining means
comprises a single piece of coiled wire or the like having at least
one non-circular convolution with an outside dimension less than
the dimension of said groove.
22. The structure claimed in claim 19 wherein said retaining means
comprises an open ended, non-circular, ring-like structure having
an outside dimension less than the dimension of said groove.
23. The structure claimed in claim 19 wherein said retaining means
comprises a closed, non-circular, ring-like structure having more
than one convolution, at least one of said convolutions having an
outside dimension less than the dimension of said groove.
24. The structure claimed in claim 19 wherein said retaining means
comprises a part of a non-circular helix, one end of said resilient
member being in a different horizontal plane than is the other end,
whereby one end of said resilient member will bear against one edge
of said groove and the other end of said resilient member will bear
against the opposite edge of said groove.
25. The structure claimed in claim 19 wherein said retaining means
is provided with a roughened surface on that part thereof which
engages said shank.
26. The structure claimed in claim 19 wherein said shank and said
perforation have a rectangular cross section, said retaining means
having a cooperating substantially rectangular configuration.
27. The structure claimed in claim 19 wherein said shank and said
shank receiving perforation have a diamond-shaped cross section,
said retaining means having a cooperating substantially
diamond-shaped configuration.
28. The structure claimed in claim 19 wherein said shank has a
shallow depression at least at one of said points of
engagement.
29. The structure claimed in claim 19 including a slot in said work
tool holder extending perpendicular to the axis of said perforation
and intersecting said groove whereby said retaining means may be
positioned in said groove through said slot.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to mining, excavating and earth working
machinery and the like, particularly to improved means for mounting
work tools, such as cutter bits or digger teeth, in holders which
are fixed to the machinery for presenting the bits or teeth in
proper working position so that they may be driven against the face
of the material to be mined, excavated or worked.
2. Description of the Prior Art
In the present specification most of the embodiments of the present
invention will be described as applied to work tools and holders
therefor as applied to mining machines, excavating apparatus and
earth working machines and the like, including trenching machines,
wheel type and chain type. It will be apparent to those skilled in
the art, however, that uses other than holding various mining bits
and trenching teeth in place may be made of the invention.
Cutter bits and holders to which the present invention may be
applied are shown in U.S. Pat. Nos. 2,613,069; 2,950,096;
2,965,365; 3,057,609; 3,093,365; 3,114,537; 3,397,012 and
3,397,013. In some instances the cutter bit or work tool is
rotatable within the holder, in others it is not. (The terms cutter
bit and work tool are intended to encompass digger teeth, trenching
teeth and the like; the terms work holder and mounting means are
intended to encompass the various structures, such as lugs, socket
members, bit holders and teeth holders, which receive the work
tools to make them operable by and with the particular machinery
involved.) Most of these work tool, work holder arrangements are of
the knock-in, pry-out type as will be seen from an examination of
the patents referred to herein. The foregoing patents show various
resilient retaining means for releasably maintaining the work tool
within the work holders. As the shank receiving perforation,
however, becomes worn during use and the work tool shank is more
loosely accomodated therein, the shank holding capabilities of such
retaining means are diminished.
Although no search of the prior patent art has been conducted with
respect to the improved resilient retaining means for joining work
tools and holders according to the present invention, it is
believed that the patents above noted are representative of the
general state of the art. FIGS. 6 and 7 of Pat. No. 3,397,012 along
with Pat. Nos. 3,498,677; 3,499,685 and 3,519,309 may be the
closest prior patent art.
SUMMARy OF THE INVENTION
The present invention relates particularly to improved resilient
retaining means for securing the shanks of work tools, such as mine
cutter bits, earth digging teeth and trenching teeth, in their
respective holders. For the most part, as indicated, these
retaining means are resilient and will maintain the work tool
shanks in their respective shank receiving perforations by
friction; these retaining means will function efficiently in spite
of wear on the shank receiving perforation or even on the shank.
Thus, as indicated, certain, at least, of the retaining means of
the present invention are capable of functioning with full
efficiency despite wear of the shank receiving perforation. Despite
long use and wear of the work tool and work tool holder assembly,
the work tool will be tightly and adequately retained in its
respective shank receiving perforation.
The foregoing results constitute the objects of this invention;
indeed, as will be amplified in the description to follow, such
results and objects are achieved by the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 s a side elevational view of a work tool and work tool
holder assembly illustrating one type of resilient retaining means
according to the present invention.
FIG. 2 is a cross sectional view of a lug similar to that which is
a part of the assembly of FIG. 1 but without any work tool or
retaining means being depicted.
FIG. 3 is a perspective view of one form of retaining means
according to the present invention.
FIGS. 4 and 5 are perspective views of coiled retaining means.
FIGS. 6 and 7 are perspective views illustrating retaining means
which are well suited for work tools having non-circular shanks
such as are depicted in FIG. 27.
FIG. 8 is a perspective view of a retaining means for work tools
having shanks of rectangular cross section.
FIGS. 9A, 9B and 9C are plan views of other retaining means for
work tools having shanks of rectangular cross section.
FIG. 10 is a plan view of a modified form of the retaining means
depicted in FIG. 3.
FIGS. 11, 12 and 13 are perspective views of the retaining means
shown in FIG. 10 showing its characteristics and certain
modifications in greater detail.
FIGS. 14 and 15 are perspective views of modified forms of the
coiled retaining means depicted in FIGS. 4 and 5.
FIGS. 16 and 17 are perspective views of modified forms of the
retaining means shown in FIGS. 6 and 7.
FIG. 18 is a perspective view of a modified form of the retaining
means depicted in FIG. 8.
FIGS. 19A, 19B and 19C are plan views of modified forms of the
retaining means shown in FIGS. 9A, 9B and 9C.
FIG. 20 is a perspective view, with parts broken away, of a work
tool shank having one of the retaining means of this invention held
captive thereon.
FIG. 21 is a sectional view, with parts broken away, through the
shank and retaining means of FIG. 20, a portion of the perforated
work tool holder also being shown.
FIG. 22 is a side elevational view of a lug like that depicted in
FIG. 2 and illustrating arrangements by which a retaining means may
be gotten out of the lug when desired.
FIG. 23 is an exploded view, with parts in section. showing a work
tool and work tool holder arrangement wherein the retaining means
which clamps on the work tool shank is held captive in the holder,
both the shank and retaining means being rotatable together with
respect to the holder.
FIG. 24 is an exploded view, with parts in section, of a
modification of the work tool shank and retaining means of the
general type depicted in FIG. 23.
FIG. 25 is a side elevational view of a work tool and work tool
holder assembly illustrating the use of more than one resilient
retaining means of the present invention.
FIG. 26 is a cross sectional view of a work tool holder similar to
that shown in FIG. 25, and illustrates another form of resilient
retaining means.
FIG. 27 is a side elevational view, partly in cross section,
illustrating a retaining means according to this invention as
applied to a modified work tool - work tool holder .
FIG. 28 is a side elevational view, partly in cross section,
illustating a retaining means according to this invention as
applied to yet another work tool - work tool holder assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 3 through 9C and 25 through 28 of the instant
continuation-in-part application are exact reproductions, except
for reference numerals, of FIGS. 41, 33, 34, 47, 48, 45, 44 A, 44B,
44C, 1, 6, 43 and 46 respectively of the parent application Ser.
No. 842,791. These figures, therefore, and the embodiments of the
invention they illustrate, will be described first.
In some of the description to follow, reference will be made to
structures such as cutter bits and lugs; these are usually
associated with the mining industry. It is to be remembered,
however, as pointed out in some of the foregoing material, that the
present invention has much wider application than that. Cutter bits
are but a portion of the items to which the present invention may
be applied, other items bearing such designations as digger teeth
and trenching teeth; the term "work tool" used herein is intended
to cover all of these items and others similar thereto, although in
some instances the items will be referred to specifically.
Similarly, designations such as lugs, mounting means, socket
members, bit holders, teeth holders and the like are considered as
being closely related and included within the terms "work tool
holder" and "holder". Again, some specific references may be made
to these various items from time to time. All such terms as just
described herein, however, are not to constitute a limitation on
the instant invention except insofar as they are specifically set
forth in the subjoined claims.
FIG. 25 illustrates a cutter bit (work tool) - lug (work tool
holder) assembly of the present invention. The cutter bit is
generally indicated at 50 and the lug is generally indicated at 51.
The lug comprises a body 52.
The lugs of the present invention may be installed upon cutter
chains, cutter wheels, rotary cutter bars or cutter arms of mining
machinery (usually by welding them to the driven element which
carry them) and they may be oriented at different angularities to
the driven elements so that the cutting points of the various bits
will form a cut of sufficient width to permit the passage of the
driven element and its appurtenances.
The body 52 has a shank receiving perforation 53. The axis of the
shank receiving perforation 53 is inclined toward the cutting
direction (indicated by arrow A). As used herein, the term "cutting
direction" refers to the direction in which the cutter-bit lug
assembly is moved by the driven element to which they are mounted,
irrespective of any movement of the entire mining machine
itself.
The angularity of the shank receiving perforation axis to the
cutting direction does not constitute a limitation on the present
invention. This angularity may be 90.degree. or less. An angularity
of less than 90.degree. is generally preferred so that the
component of force tending to shove the cutter bit into the shank
receiving perforation is greater and so that the resultant cutting
stresses on the bit will be more nearly in line with the bit
axis.
The bit 50 comprises an elongated shank 54, in this instance
preferably of circular cross section. The upper end of the shank
terminates in a clearance surface 55 lying at an angle to the shank
axis and is relieved on opposite sides as at 56 so as to form a
cutting tip 57 presenting a cutting surface substantially parallel
to the axis of the shank 54. The lower end of the shank 54
terminates in an abutment surface 58 lying at an angle to the shank
axis.
The lug body 52 has a transverse hole 59 extending through the body
and intersecting the shank receiving perforation 53. A pin 60 is
located in the hole 59 and may be replacably held or permanently
affixed therein as by welding or the like. The pin 60 may have a
length equal to or less than the length of the hole 59. The pin 60
is relieved to form an abutment surface 61 adapted to cooperate
with the abutment surface 58 on the cutter bit. The abutment
surface 61 may exist only on that portion of the pin lying within
the shank receiving perforation. On the other hand, the surface 61
may extend the full length of the pin. The latter arrangement has
two advantages. First of all, it provides lateral bleed holes for
fines and other foreign material which might tend to accumulate in
the shank receiving perforation. It is for this same reason that
the shank receiving perforation 53 preferably extends through the
lug body 52 forming an opening both at the top and bottom thereof.
Secondly, if the surface 61 extends throughout the length of the
pin 60, this would enable the insertion of a drift through the open
portion of hole 59 should difficulty be encountered in removing the
cutter bit, or if the exposed part of the cutter bit were to be
broken away, leaving a portion of the bit inside the shank
receiving perforation.
FIG. 25 illustrates one form of a novel retaining means for
maintaining the shank 54 in the shank receiving perforation 53 in
accordance with the present invention. In this instance, the inside
surface of the perforation 53 has an annular notch or groove 62
formed therein. The notch 62 is adapted to receive one or more
resilient, C-shaped elements of metal or the like. For purposes of
an exemplary showing, two C-shaped metal elements 63 and 64 are
illustrated. The elements 63 and 64 are substantially identical.
They have an outside diameter greater than the diameter of the
shank receiving perforation but slightly less than the diameter of
the annular notch 62. The rings 63 and 64 have an inside diameter
slightly less than the diameter of the cutter bit shank 54. In use,
the C-shaped elements are contracted (which can be accomplished by
virtue of the fact that the ends of each element are spaced from
each other) and are shoved into the shank receiving perforation 53
until they reach the annular notch or groove 62. When the notch 62
is reached, the C-shaped elements are captively held in the annular
notch or groove 62.
The cutter bit 50 may be mounted in the lug 51 by inserting it into
the shank receiving perforation. Since the diameter of the cutter
bit shank 54 is greater than the inside diameter of the elements 63
and 64, the bit must be forced therethrough. A blow by a suitable
tool will be sufficient to cause the bit 50 to assume its proper
seated position against the abutment surface 61, as shown in FIG.
25. The elements 63 and 64 frictionally engage the shank 54 and
prevent removal thereof by centrifugal force or other forces
operating to remove the bit. During normal cutting conditions,
there will be a large component of force tending to urge the bit
towards its seated position.
Removal of the cutter bit 50 may be accomplished merely by engaging
the exposed portion of the bit by a suitable tool and pulling
upwardly thereon.
FIG. 26 illustrates a lug in every way identical to that shown in
FIG. 25, and like parts have been given like index numerals. The
figure illustrates, however, the use of another form of resilient
retainer according to the present invention. In this instance, a
resilient ring 65 of rubber or the like is provided. The ring has
an outside diameter greater than that of the shank receiving
perforation 53, but less than that of the annular notch 62. As in
the case of the elements 63 and 64 of FIG. 25, the inside diameter
of the ring 65 is less than the diameter of the cutter bit shank
54. Insertion and removal of a cutter bit in the lug of FIG. 26 can
be accomplished in the same manner described with respect to FIG.
25. The resilient ring 65 will maintain the cutter bit in place in
substantially the same manner as described with respect to elements
63 and 64.
With respect to the retainers just described, it is important to
note that their retaining action is not affected by wear of the
shank receiving perforation 53. They frictionally engage the cutter
bit shank and operate primarily on the upper and lower faces of the
annular notch or groove 62. These retaining means are not as
constantly worked as are prior art resilient retainers so that
hysteresis in the case of rubber or the like and fatiguing in the
case of metal or the like are greatly reduced.
The resilient C-shaped elements 63 and 64 may have any suitable
cross sectional configuration. This is illustrated, for example, in
FIG. 3. Here the resilient C-shaped element 63a is shown as having
a rectangular cross sectional configuration. Further, the elements
63 and 64, or 63a, may be provided with serrations on that portion
thereof which engages the cutter bit shank. Such serrations are
illustrated at 63b in FIG. 3.
In the assembly shown in FIG. 25, it will be understood that
although the shank 54 and the shank receiving perforation 53 are
circular in cross section, the angularity and interaction of the
shank abutment surface 58 and the lug abutment surface 61 will
prevent any rotation of the bit about its axis. The same
interaction and angularity will also tend to cause the bit 50 to be
self-aligning during insertion into the shank receiving perforation
53.
In FIG. 25 the cutter bit shank 54 and shank receiving perforation
53 are (for purposes of clarity) illustrated by separate dashed
lines. These dashed lines are not intended to be indicative of
clearance dimensions. It will be understood by one skilled in the
art that the respective diameters of the shank 54 and perforation
53 will be so sized as to permit a sliding fit of the shank within
the perforation. Prolonged use of the assembly will cause wear of
the parts, particularly the perforation 53, and the clearance
dimensions will be changed thereby.
Most of the embodiments of the present invention are, however,
adapted to both reduce and counteract such wear. The combination of
two factors, the interaction of abutment surfaces 58 and 61 and the
frictional engagement of the retaining means 63-64 on the bit shank
while not being fixedly held in the lug, yield two important
results. First of all, when the assembly is moved in the cutting
direction (arrow A of FIG. 25) the material being cut will exert a
force on the cutter bit, one component of which is directed
rearwardly (in a direction opposite that of arrow A) and another
component of which is directed downwardly. The nature of the
retaining means and the cooperation of abutment surfaces 58 and 61
not only permit but also encourage a full line or
surface-to-surface contact between adjacent rear surfaces of the
perforation 53 and shank 54. Thus all along the surface to which
the lead line of index numeral 53 is directed there will be contact
between the shank and the surface of the shank receiving
perforation. It has been found in actual field use that this
greatly reduces wear of the parts, particularly wear of the shank
receiving perforation 53.
As wear does occur, the two above mentioned factors together with
the two above mentioned components of force cooperate to ensure
that the cutter bit remains fully seated with the above noted line
or surface-to-surface contact. Meanwhile, the retaining means of
the present invention maintain their full effectiveness.
These two results or features (i.e. full line or surface-to-surface
contact and proper seating and retention in spite of wear) have
rendered the useful life of cutter chains, cutter wheels, cutter
arms and the like, no longer so dependent on the wear of the shank
receiving perforations. Thus, service life is greatly
increased.
FIGS. 4 and 5 illustrate additional embodiments of resilient means
according to this invention and suitable for the cutter bits
described. In FIG. 4, there is illustrated a retaining means 66
comprising a single piece of coiled, resilient wire having about 1
3/4 convolutions. The retainer 67 in FIG. 5 is similar to that of
FIG. 4, but has about 2 3/4 convolutions. The resilient retaining
means 66 and 67 are adapted to be used in much the same way as the
C-shaped elements 63 and 64 in FIG. 25. The retainers 66 and 67
will have an outside diameter greater than the diameter of the
shank receiving perforation 53 of the lug, but less than the
diameter of the notch or groove 62. Either of the retainers 66 and
67 may be spirally or transversely compressed and inserted into the
shank receiving perforation 53, and will snap into place when they
reach the notch or groove 62.
The retainers 66 and 67 have an inside diameter less than the
diameter of the cutter bit shank. In this way, when the cutter bit
shank is inserted into the shank receiving perforation in the lug,
it will be frictionally engaged by the resilient retainer 66 or
67.
Retainers 66 and 67 function in an identical manner. It has been
discovered that, by utilizing a series of loops, the holding power
of a resilient retainer can be appreciably multiplied. Thus, the
resilient retainers 66 and 67 can be expected to have a greater
holding power than the C-shaped elements 63 and 64. Similarly, the
holding power of retainer 67 should be greater than that of
retainer 66. It will be understood by one skilled in the art that
retainers 66 and 67 may have any desired cross sectional
configuration and may be provided with serrations, all as is shown
in FIG. 3 with respect to the retainer 63a, 63b.
FIG. 27 illustrates the application of the principles of the
present invention to cutter bit - lug assemblies of a type having a
shank and a shank receiving perforation of non-circular cross
section.
The cutter bit or other work tool as hereinbefore explained,
generally indicated at 68 has a head portion 69, a shank portion 70
and a hard cutting tip 71. The head may be provided with one or
more surfaces 72 which may be engaged by an appropriate pry-out
tool. The shank 70 is illustrated as being rectangular in cross
section. The bottom end of this shank 70, in this instance, is
provided with an abutment surface 73 sloping downwardly and
rearwardly.
The lug or work tool holder 74 has a shank receiving perforation 75
of rectangular cross section. In this instance the lug is provided
with a transverse hole 76 having a rod-like element 77 therein.
This rod-like element is, in every way, similar to the pin 60 in
FIG. 25. The rod 77 has an abutment surface 78 cooperating with the
bit abutment surface 73. (With this particular arrangement it is no
longer necessary to provide a gauge-determining abutment surface in
association with the bit head 69.)
The shank receiving perforation 75 is provided with an annular
notch 79. This notch may be circular in configuration to receive
resilient retaining means of the general type shown in FIGS. 25, 4,
5 and 3 or the resilient band type shown in FIG. 26. Alternatively,
the notch may be rectangular, conforming generally to the cross
section configuration of the shank receiving perforation. When this
is the case, use may be made of a resilient band-type retainer, or
one or more of the retainers next to be described.
A resilient retaining means is shown at 80 in FIG. 27. The
retaining means 80 may comprise one or more open ring-like
structures of the type shown at 81a, 81b or 81c in FIGS. 9A, 9B and
9C respectively or the retainer 82 of FIG. 8.
In FIG. 8, the retainer 82 is similar to that shown in FIG. 9A but
is provided with more than one convolution, in the manner of those
retainers shown in FIGS. 4 and 5.
All of the retainers of FIGS. 9A, 9B and 9C may be compressed and
inserted in the notch 79 (FIG. 27), or they may be introduced
through a slot extending from the notch 79 through any of the sides
of the lug. Such a slot is indicated in dotted lines at 83 in FIG.
27. Once the bit shank is in place the retainer cannot exit through
the slot. By the same token, the slot may be provided with
shoulders at its entrance to the notch 79 so that the retainer
means will be substantially captively held in the notch 79. The
retainer means could be so sized and configured as to have a snap
fit in the notch 79, once it had passed thereinto from the slot
83.
All of the last mentioned retainers will frictionally engage the
bit shank at two or more points. When desired, the bottom end of
the bit shank may be provided with appropriate relief to aid its
insertion into the retaining means.
In the embodiment of FIG. 27, the resilient retainer 80 again is
captively held in the notch 79 and frictionally engages the shank
70. As illustrated, the cutter bit 68 will be adequately and firmly
retained and a full surface-to-surface engagement will be
maintained between the rear shank surface 70a and the rear shank
receiving perforation surface 75 a.
The retaining means of FIGS. 9 and 8 could have any cross sectional
configuration and could be provided with serrations and/or granules
in the manner shown with respect to the retainers of FIGS. 3, 12
and 13.
FIG. 28 illustrates the application of the principles of the
present invention to cutter bit (work tool) - lug (work tool
holder) assemblies of the type taught in U.S. Pat. No. 3,093,365.
In this instance, the bit 84 is of the double-ended trapezoidal
type, having cut surfaces 85 and 86 each terminating respectively
in cutting tips 87 and 88. While the invention is not so limited,
such bits generally have substantially diamond shaped cross section
and the bit 84 is so illustrated. When the cutting tip 87 is being
used, the surface 86 will serve as an abutment surface. Similarly,
when the cutting tip 88 is being used, the surface 85 will serve as
an abutment surface.
The lug body 89 has a shank receiving perforation 90 extending
therethrough. It is preferable that the shank receiving perforation
90 extend all the way through the body 89 so as to prevent the
accumulation of fines and other foreign material within the shank
receiving perforation and to permit the use of a drift to remove
the bit, where possible.
The cross sectional configuration of the shank receiving
perforation 90 will depend, in large part, on the cross sectional
configuration of the bit. In this instance, the perforation 90 is
illustrated as having a substantially diamond shaped cross section.
It will be understood by one skilled in the art, however, that the
bit 84 and the shank receiving perforation 90 could have circular
or other cross sectional configuration, as desired.
The lug 89 is provided with a transverse hole 91 having a rod-like
member 92 permanently or removably affixed therein. As in the case
of the rod-like element in FIG. 25, the element 92 may have a
length equal to or less than the hole 91. The element 92 has an
abutment surface 93 thereon, adapted to cooperate with the surface
86 or the surface 85, depending upon the orientation of the bit 84.
Again, the surface 93 may extend throughout the length of the
rod-like element 92 or be present only on that portion of the
rod-like element which extends into the shank receiving perforation
90.
The shank receiving perforation 90 is provided with an annular
notch 94 to receive retaining means, indicated at 95. The retaining
means may be of the general type shown in FIGS. 25, 4, 5 or 3, or
it may be a resilient band of the type shown in FIG. 26.
In FIG. 6, a retaining means similar to that shown in FIG. 25 is
illustrated at 96. This retaining means differs from that of FIG.
25 only in its diamond shaped configuration. FIG. 7 illustrates a
retaining means 97 similar to that of FIG. 6 but having more than
one convolution in the manner of those retaining means shown in
FIGS. 4 and 5. Again it will be understood by one skilled in the
art that the retaining means of FIGS. 6 and 7 may have any desired
cross sectional configuration and may be provided with serrations
and/or granules in the manner described with respect to the
retainers of FIG. 3, 12 and 13.
The retaining means of FIG. 6 will act in substantially the same
manner described with respect to the embodiments of FIGS. 9A, 9B,
9C and 8. It may also be inserted into the notch 94 in any of the
ways taught with respect to the retainers 81a, 81b, 81c and 82. The
retaining means of FIG. 7 may be inserted via a lateral slot of the
type described at 83 in FIG. 27.
It will be noted that with the above described types of retaining
means and with the orientation of the abutment surface 93 and
surfaces 85 and 86, when the bit is moved in the cutting direction
(arrow A) the components of force acting thereon will tend to
maintain the bit in fully seated position with full
surface-to-surface contact between the bit surface 84a and the
shank receiving perforation surface 90a.
It will be immediately evident to one skilled in the art that the
bit-lug assembly of FIG. 28 is far simpler than previous assemblies
incorporating such bits. The lug need no longer be a multi-piece
member having latch or other means for retaining the bit.
Departing now somewhat from the disclosures originally contained in
copending parent application Ser. No. 842,791, as described in
connection with FIGS. 25 through 28 and FIGS. 3 through 9C, above,
the showing of FIGS. 1, 2 and 10 through 24 will now be considered.
Wherever conveniently possible, like numerals will be used to
designate like parts.
FIG. 1 is much like FIG. 25 with respect to the lug body 52a, the
perforation 53a and the bit shank 54a. Similarly, a hole 59a is
provided in the lug to receive the pin 60a which has the abutment
surface 61a thereon. A notch or groove 62a is provided in the wall
defining the shank receiving perforation 53a. The C-shaped
resilient retaining ring 98, although generally similar to the
elements 63 and 64 of FIG. 25, is specifically different.
Referring now to FIGS. 10 and 11, the resilient retaining means 98
is shown in greater detail. The retainer 98 is illustrated as
forming a part of a helix. Note that the central portion 98a is on
a slant with respect to the horizontal, the end 98b being above
this portion and the end 98c extending below this portion. When the
retainer 98 is forced into the groove 62a of lug 52a of FIG. 1, for
example, the end 98b will bear against the upper wall defining the
groove 62a while the end 98c will bear against the lower wall. This
constitutes an improvement over the arrangement of FIG. 25, and
those like it, in that longitudinal or axial "jiggling" of the
retaining means and/or bit shank is eliminated. Arrangements like
that shown in FIG. 25 must of practical necessity permit a certain
amount of play; as just indicated, this play may be eliminated by
modifying the retaining element to impart to it the configuration
shown in FIGS. 1, 10 and 11. Another way of picturing this, is to
consider the retainer 98 as having been bent or twisted in order to
spread the ends 98b and 98c away from one another a distance
somewhat more than the width of the groove into which the member 98
will be forced. This will produce the result illustrated in FIG.
1.
FIGS. 12 and 13 illustrate further refinements. In FIG. 12 the
interior or bit shank gripping surface of the resilient retaining
member 98 is shown as provided with serrations 98d like those
discussed in connection with 63b of FIG. 3. In FIG. 13 improved
gripping action for the retainer 98 is obtained by affixing
granular material to the inner side thereof as indicated at
98e.
FIGS. 14 through 19C illustrate other forms of improved resilient
retaining elements. The elements of these figures correspond
generally to those shown in FIGS. 4 through 9C respectively. In
each instance, however, the retainers of FIGS. 14 through 19C are,
in effect, spread out so that each is initially, when at rest,
wider than the groove into which it will eventually be forced
thereby to obtain the improved gripping action just described in
connection with FIGS. 1 and 10 through 13.
Thus, it will be observed that the resilient retaining means 99 of
FIG. 14 generally correspond to the means 66 of FIG. 4, the
resilient retaining means 100 of FIG. 15 generally corresponds to
the retainer 67 of FIG. 5, the resilient retaining means 101 of
FIG. 16 generally corresponds to the retainer 96 of FIG. 6, the
resilient retaining means 102 of FIG. 17 generally corresponds to
the retainer 97 of FIG. 7, the resilient retaining means 103 of
FIG. 18 generally corresponds to the retainer 82 of FIG. 8 and the
resilient retaining means 104a, 104b and 104c generally correspond
to the retainers 81a, 81b and 81c of FIGS. 9A, 9B and 9C. In all of
these FIGS. 14 through 19C, the free ends of the respective
resilient retaining means are, in effect, bent away from one
another. In those arrangements involving more than one convolution,
adjacent convolutions are separated a slight bit one from the
other. As indicated above, the purpose for the modifications just
described is to obtain the action described in connection with
FIGS. 1 and 10 through 13.
Further refinements are illustrated in FIGS. 2 and 22. FIG. 2 is
like FIG. 26 but without any retainer being shown in the notch or
groove 62. FIG. 22 is like FIG. 2 except that it is not in section.
The resilient retaining elements of FIGS. 10 through 19C, due to
the fact that they are initially wider than the width of the groove
into which they will be forced, tend to fit very tightly within
their respective grooves, a fact which often makes them difficult
to remove when that is desired. This problem may be overcome in a
couple of ways, both of which are illustrated in FIG. 22, although
in practice only one or the other would ordinarily be utilized. The
preferred manner of facilitating the removal of a retaining means
from, for example, the groove 62 of FIG. 22 is to provide a hole
105 in the lug 52 extending at least to the groove 62; it may be
desirable to extend this hole 105 completely through the lug. A
suitable punch or pin may be inserted through this hole 105 to
contact the retainer and force it out of the groove 62. Similarly,
as also indicated in FIG. 22, a groove in the wall of the lug
defining the perforation 53 could extend to the groove 62 so that a
suitable instrument could be moved through such groove 106 to come
behind the retainer and pry it from the groove 62.
A modification in the invention and utilization thereof is
illustrated in FIGS. 20 and 21. The shank of any work tool embraced
within the scope of this invention as explained earlier herein is
shown at 107. In this instance the shank itself is provided with an
annular groove 108. A resilient retaining member 109 is captively
held within this groove 108. The groove 108 defines a neck 110 as a
part of the shank 107. The resilient retainer 109 may be like any
of those shown in FIGS. 1 and 10 through 19C, particularly like
those of FIGS. 10 through 15. The exterior of the retainer 109 may
be serrated as discussed, for example, in connection with the inner
surface 98b of FIG. 12 or it may be provided with granular material
as indicated at 98e with respect to the interior surface of the
member shown in FIG. 13; in FIG. 20 this arrangement is generally
indicated at 109a. As will be seen from an examination of FIG. 21,
the retainer 109 is specifically like that shown in FIG. 10; this
is for purposes of illustration only.
In its relaxed condition the exterior diameter of the resilient
retainer 109 is greater than the diameter of the perforation 111
provided in the lug 112 and into which the shank 107 will be
forced. To facilitate insertion, the entrance end of the
perforation 111 should be countersunk. The interior diameter of the
resilient retaining member 109 is such that when the shank 107 and
retainer 109 are received in the perforation 111, whereby to
compress the retainer 109, such retainer 109 will still be spaced
from the neck portion 110 of the shank 107. This relationship, plus
the fact that one end portion of the retainer 109 bears against the
upper wall defining the groove 108 while the other end portion of
the retainer 109 bears against the lower wall defining the groove
108, insures that the shank and retainer will be prevented from
longitudinal jiggling within the perforation 111 of the lug
112.
Further modifications of the invention are shown in FIGS. 23 and
24. In FIG. 23 a work tool shank is indicated at 113 and a work
tool holder is indicated at 114. The holder 114 is provided with a
shank receiving perforation 115 and an abutment 116. An annular
notch or groove 117 is provided in the holder 114. A resilient
retainer 118 is captively held within the groove 117. The interior
surface of this retainer 118 may be serrated or provided with
granular material as discussed in connection with others of the
various figures and as is generally indicated at 118a. In its
relaxed condition, the interior diameter of the retainer 118 is
smaller than the outside diameter of the shank 113. As illustrated
in FIG. 23, the retainer 118 is generally like that shown at 63b in
FIG. 3.
The arrangement of FIG. 23 emphasizes the fact that the resilient
retaining means of the present invention may be utilized with work
tools and work tool holders wherein the tool is either rotatable or
non-rotatable within its holder. Thus, although many of the figures
and illustrations previously discussed herein show cooperating
abutment surfaces on the work tool shank and work tool holder, or
in association with the work tool holder, whereby rotation is
prevented, this is not a limitation on the improved resilient
retaining means according to the present invention.
In FIG. 24 additional holding power is obtained by providing the
retainer 119 with a protuberance or bead 120 adapted to engage
within a shallow groove 121 on the work tool shank 113.
In the arrangements of FIGS. 1 through 19C and 22 the resilient
retainer is held captive within a groove provided in the lug; this
retainer frictionally engages the shank and the work tool is
non-rotatable with respect to the work tool holder. In the
arrangement of FIGS. 20 and 21 the resilient retainer is captive
within a groove provided on the shank of the work tool, the
retainer being formed on a helix and the like, such retainer
frictionally engaging the work tool holder; by this arrangement the
work tool is rotatable with respect to the retainer and work tool
holder. In the arrangement of FIGS. 23 and 24 the resilient
retainer is held captive within a groove provided in the lug, such
retainer frictionally engaging the shank of a work tool; in this
instance the work tool and retainer, together, are rotatable within
the shank receiving perforation of the work tool holder.
Modifications may be made in this invention without departing from
the scope and spirit thereof. As pointed out in the above mentioned
U.S. Pat. No. 3,622,206, for example, any of the work tools
contemplated may be provided with a shallow depression to receive
the various retaining means taught herein. Such a depression would
increase the retaining ability of the retaining means, but should
be shallow so as not to constitute a significant stress raiser. The
depression should be so configured as not to present a shoulder
interfering with the pry-out feature of the work tools. Such
depression may lie on one side only of the work tool shank, or more
than one depression may be provided located at various positions
about the shank. Similarly, the depression may be a continuous
annular one extending fully about the shank. This is illustrated at
222 in dotted lines in FIG. 50 of the said parent application. In
using the term depression it is to be understood that what is meant
is a configuration which will help to increase the holding power of
the retaining means with respect to the shank, but not to a degree
to preclude the pry-out feature. A modification of such an
arrangement is shown in FIG. 24 of the instant application.
Although this invention has been described with respect to certain
particular structures and arrangements, this has been for purposes
of illustration only, and the invention is not to be limited to
such specific structures and arrangements except insofar as they
are positively set forth in the subjoined claims.
Modifications may be made in the invention without departing from
the spirit of it.
* * * * *