U.S. patent number 3,736,710 [Application Number 05/094,812] was granted by the patent office on 1973-06-05 for four-section fully hydraulically operated crane boom having three individually supported single piston rams contained within fly section.
This patent grant is currently assigned to Walter Kidde & Company, Inc.. Invention is credited to Russell L. Sterner.
United States Patent |
3,736,710 |
Sterner |
June 5, 1973 |
FOUR-SECTION FULLY HYDRAULICALLY OPERATED CRANE BOOM HAVING THREE
INDIVIDUALLY SUPPORTED SINGLE PISTON RAMS CONTAINED WITHIN FLY
SECTION
Abstract
A four-section fully hydraulically operated telescoping crane
boom is constructed so that the three operating rams of the boom
can be contained within the boom fly section and are independently
supported and operated. Single piston rams are utilized throughout.
The ram which interconnects the base section and the inner
mid-section of the boom is reversed from the conventional
arrangement with the rod end of this ram anchored to the base
section and the cylinder end cantilevered forwardly from a rear
pivotal connection with the inner mid-section of the boom and
having a sliding support and guide means on its forward end
engaging a core or box forming a part of the outer mid-section of
the boom. As a result of the arrangement of the rams the vertical
heights of the several boom sections can be made nearly equal and
the amount of metal utilized in the boom is minimized while
maintaining maximum rigidity.
Inventors: |
Sterner; Russell L.
(Greencastle, PA) |
Assignee: |
Walter Kidde & Company,
Inc. (Clifton, NJ)
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Family
ID: |
22247318 |
Appl.
No.: |
05/094,812 |
Filed: |
December 3, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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75886 |
Nov 28, 1970 |
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Current U.S.
Class: |
52/115; 52/848;
52/114; 212/349 |
Current CPC
Class: |
B66C
23/705 (20130101) |
Current International
Class: |
B66C
23/00 (20060101); B66C 23/70 (20060101); E04h
012/34 (); B66c 023/04 (); B66c 023/54 () |
Field of
Search: |
;52/114,115,731 ;212/55
;91/167 ;182/51 ;214/141 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abbott; Frank L.
Assistant Examiner: Braun; Leslie A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of prior co-pending
application Ser. No. 75,886 filed Sept. 28, 1970 for "Trapezoidal
Telescoping Crane Boom."
Claims
I claim:
1. A four-section fully hydraulically operated crane boom
comprising inner and outer mid-sections, and a fly section all
telescopically inter-fitting within a base section, a first ram
having its rod end connected with the base section and its cylinder
connected with the inner mid-section of the boom near the rear ends
of the cylinder and inner mid-section, said cylinder extending
substantially forwardly of its point of connection with the inner
mid-section, a second ram having connections with the inner and
outer mid-sections, a core member extending over said second ram
and connected with the outer mid-section near the rear ends of the
outer mid-section and core member, the rod end of the second ram
connected with the core member near the forward end of the core
member, a third ram having connections with the outer mid-section
and the fly section of the boom, said rams individually supported
and independently operable, a rest structure for the forward end
portion of said cylinder of the first ram slidably contacting the
core member, the vertical height of all said boom sections being
nearly equal, and said fly section constructed to telescope over
all of the rams in the retracted positions thereof to substantially
enclose them.
2. A four-section fully hydraulically operated crane boom
comprising
inner and outer mid-sections, and a fly section all telescopically
inter-fitting within a base section,
a first ram having its rod end pivotally secured to said base
section near the rear end of the base section and having its
cylinder end pivotally connected with the inner mid-section near
the rear ends of the cylinder and inner mid-section,
the cylinder of said first ram extending substantially forwardly of
its point of connection with the inner mid-section,
a second ram having connections with the inner and outer
mid-section,
said second ram having its cylinder end connected to the inner
mid-section,
a hollow core member engaging over the second ram and connected
near its forward end to the rod end of the second ram and connected
near its rear end to the outer mid-section near the rear end of the
outer mid-section,
a third ram connected between the outer mid-section and the fly
section of the boom,
said rams individually supported and independently operable,
a rest structure for the forward end portion of said cylinder of
the first ram slidably contacting the core member,
whereby retraction of said rams allows the fly section to telescope
over all of the rams to substantially enclose them.
3. The structure of claim 2 and said connection between the rod end
of the first ram and said base section being a resilient pivotal
connection with restrained freedom of movement in the vertical
direction, the connection between the rear ends of the core member
and outer mid-section also being a pivotal connection.
4. The structure of claim 2 in which said rest structure comprises
a wear pad on the cylinder of the first ram near the forward end of
the cylinder having sliding engagement with the core member and
supporting the cantilevered end of the cylinder of the first ram in
all operative positions of the boom.
5. A crane boom as set forth in claim 4 and another wear pad on
said core member near its forward end having sliding engagement
with a part of the fly section.
6. The structure of claim 2 and said hollow core member including a
substantially flat top wall having side longitudinal edge portions
which project outwardly of the opposite side walls of the core
member, and said rest structure comprising a bearing and guide unit
on the cylinder of the first ram near the forward end of the
cylinder and including a wear pad slidably engaging the top wall of
said core and a pair of laterally spaced opposed guide shoes
engaging below said longitudinal edge portions in close proximity
to the side walls of said core.
7. A crane boom as set forth in claim 2 in which said third ram has
its rod end connected to said fly section and its cylinder end
connected with the outer mid-section, and said first ram disposed
bodily between the second and third rams in vertically stacked
relation.
8. A crane boom as set forth in claim 2, and a wear pad on the
cylinder of said third ram having sliding engagement with a part of
said fly section.
9. A four-section fully hydraulically operated crane boom
comprising
inner and outer mid-sections,
and a fly section all telescopically inter-fitting within a base
section,
a first ram having its rod end resiliently pivotally connected with
restrained freedom of movement in the vertical direction with the
base section and its cylinder connected with the inner mid-section
of the boom near the rear ends of the cylinder and inner
mid-section,
the cylinder of said first ram extending substantially forwardly of
its point of connection with the inner mid-section,
a second ram having connections with the inner and outer mid
sections,
a core member extending over said second ram and pivotally
connected with the outer mid-section near the rear ends of the
outer mid-section and core member,
the rod end of said second ram connected with the core member near
the forward end of the core member,
a rest structure for the forward end portion of said cylinder of
the first ram slidably contacting the core member,
a third ram having connections with the outer mid-section and the
fly section of the boom,
said rams individually supported and independently operable,
said resilient pivotal connection comprising a cross pin
element,
a sleeve on the cross pin element,
ball bearings supporting the opposite ends of the cross pin
element,
guide elements having vertical guide slots for said ball
bearings,
and cushioning springs above and below the ball bearings in said
guide elements,
whereby retraction of said rams allows the fly section to telescope
over all of the rams to substantially enclose them.
10. The structure of claim 9 and said cushioning springs secured to
top and bottom portions of said guide elements, and friction shoes
connected with said springs and slidably contacting the peripheries
of said ball bearings and urged yieldingly against the peripheries
by said springs.
11. A four-section fully hydraulically operated crane boom
comprising
inner and outer mid-sections,
and a fly section all telescopically inter-fitting within a base
section,
a first ram having its rod end resiliently pivotally connected with
restrained freedom of movement in the vertical direction with the
base section and its cylinder connected with the inner mid-section
of the boom near the rear ends of the cylinder and inner
mid-section,
said cylinder extending substantially forwardly of its point of
connection with the inner mid-section,
a second ram having connections with the inner and outer
mid-sections,
a third ram having connections with the outer mid-sections and the
fly section of the boom,
said rams individually supported and independently operable,
said resilient pivotal connection comprising a cross pin element, a
sleeve on the cross pin element,
ball bearings supporting the opposite ends of the cross pin
element,
guide elements having vertical guide slots for said ball
bearings,
and cushioning springs above and below the ball bearings in said
guide elements,
whereby retraction of said rams allows the fly section to telescope
over all of the rams to substantially enclose them.
12. A crane boom as set forth in claim 11 and said cushioning
springs secured to top and bottom portions of said guide elements,
and friction shoes connected with said springs and slidably
contacting the peripheries of said ball bearings and urged
yieldingly against the peripheries by said springs.
Description
BACKGROUND OF THE INVENTION
The present invention arises as a result of a need in the crane
boom art for increasingly strong telescoping boom structures and
increased flexibility of operation. While plural section
hydraulically operated telescoping crane booms including
four-section booms are known in the prior art, these have possessed
certain disadvantages from the standpoint of economy and strength
for a given amount of material utilized in their construction.
An example of a prior art four-section fully hydraulically operated
boom is shown in U.S. Pat. No. 3,315,821 to Grove issued Apr. 25,
1967. While the structure in this patent has proved very adequate
in general, the arrangement of the hydraulic rams in the structure
causes one ram to lie outside of the fly section of the boom in a
separate housing near the upper side of the boom between its base
section and inner mid-section. This arrangement results in a
substantial difference in the vertical cross sectional height
between the base section and the inner mid-section of the boom,
with a corresponding lessening of overall boom strength and lifting
capacity for a given amount of metal employed in the
construction.
Another prior U.S. Pat. No. 3,419,157 to Brady issued Dec. 31,
1968, achieves a more nearly uniform vertical height between the
four box like telescoping sections and also achieves the placement
of all rams within the fly section of the boom. However, these
features have been achieved in the Brady patent only by employing
an unusual tandum arrangement of rams and also rams which require
plural telescoping piston and cylinder sections. It is well known
that such rams are more likely to leak than the simpler single
piston types and are subject to a greater degree of sagging or
flexure when fully extended.
The present invention satisfies the need in the art for a fully
hydraulically operated four-section telescoping crane boom having
only single piston rams which are all contained inside of the fly
section and individually supported therein when the fly section is
retracted. The three rams are independently operable so that the
several sections of the boom can be extended or retracted in any
sequence desired or selected by the operator. The crane boom so
constructed can have the maximum lifting capacity for a minimum
amount of metal employed in the structure and the several
telescoping boom sections can be made in nearly uniform height in
cross section for maximum strength. In summary it can be stated
that the present invention increases the overall efficiency of
operation of the crane boom and improves the economy of
construction thereof, and these factors are achieved primarily by a
unique simplified arrangement of the operating rams as compared to
the prior art.
The boom of this invention possesses a number of other features and
advantages which will appear during the course of the following
detailed description.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is a front perspective view of a four-section hydraulically
operated telescoping crane boom in accordance with the
invention;
FIG. 2 is a side elevational view of the crane boom with the
several sections thereof retracted into the base section;
FIG. 3 is a top plan view of the retracted crane boom;
FIG. 4 is a bottom plane view thereof;
FIG. 5 is a front end elevational view of the boom;
FIG. 6 is a rear end elevation thereof;
FIG. 7 is a side elevation on a reduced scale of the crane boom in
an extended condition;
FIG. 8 is an enlarged fragmentary side elevation of the portion A
shown in FIG. 7;
FIG. 9 is a similar elevational view of the portion B in FIG.
7;
FIG. 10 is a similar view of the portion C in FIG. 7;
FIG. 11 is a similar view of the portion D in FIG. 7;
FIG. 12 is an enlarged fragmentary longitudinal vertical section
through the rear end portion of the boom in a retracted
condition;
FIG. 13 is a similar section through the front end portion of the
boom;
FIG. 14 is an enlarged transversed vertical section taken on line
14--14 of FIG. 13;
FIG. 15 is a similar section taken on line 15--15 of FIG. 12;
FIG. 16 is a similar section taken on line 16--16 of FIG. 12;
FIG. 17 is a similar section on an enlarged scale taken on line
17--17 of FIG. 12;
FIG. 18 is a fragmentary side elevational view of the pivotal ram
mounting shown in FIG. 17; and
FIG. 19 is a fragmentary side elevational view partly in section of
rear wear pad means and supporting elements.
DETAILED DESCRIPTION
Referring to the drawings in detail, wherein like numerals
designate like parts throughout, a four-section crane boom
embodying the invention is shown in its entirety in a retracted
condition in FIGS. 1 through 6. As shown, the boom comprises a base
section 25, inner and outer mid-sections 26 and 27 and a fly
section 28. In the embodiment of the invention illustrated herein,
the several telescopically fitting boom sections are trapezoidal in
transverse cross section, and each boom section comprises a top
plate 29, 29', 29" and 29'", upwardly converging side webs, 30,
30', 30" and 30'" and bottom plate assemblies 31, 31', 31" and 31'"
as clearly shown in FIG. 14. It should be mentioned that while the
arrangement of rams and associated elements forming the heart of
this invention is well suited to a trapezoidal boom structure,
nevertheless, the invention is not limited to this boom
configuration and may be employed with facility on rectangular
cross-section booms or other conventional shapes.
The details of construction of the trapezoidal crane boom are
covered in the mentioned parent application, Ser. No. 75,886, and
it is not necessary to a fully understanding of the invention to
completely describe these details of construction herein, and a
brief description of the boom structure should be sufficient. In
this connection the boom base section 25 is provided at its rear
end and lower side with a heavily reinforced transverse main pivot
unit 32 for connection with the usual boom support 33, FIG. 2, on
the turntable of the mobile crane carrier, not shown. Forwardly of
the pivot unit 32, the base section 25 is further equipped on its
bottom with a reinforced connector 34 for the usual boom lifting
cylinders 35 shown in FIG. 2. At its forward end the base section
25 has a reinforcing collar 36 including a bottom transverse
section 37 which serves to house lower forward wear pads 38 and
their retainer means, as fully disclosed in said prior application.
Similar reinforcements 36 and wear pad housings 37 are also
provided on boom sections 26 and 27. As shown in the drawings, at
least the boom sections 25, 26 and 27 have certain side web and
bottom plate reinforcing members thereon at spaced intervals and
these details are fully covered in said prior application and need
not be repeated herein. The fly section 28 of the boom is provided
generally near its vertical center with an internal transverse
reinforced web 39 extending substantially the length of the
section.
With the exception of the boom base section 25, each telescoping
boom section is equipped at its rear end and top side with wear
pads, and these are indicated at 40, 41 and 42 in FIG. 12. The
inner and outer mid-sections 26 and 27 have their rear upper wear
pads 40 and 41 mounted for pivotal movement on transverse
cylindrical bearing bars 43, secured to and supported by the tops
of upwardly converging support bars 44, suitably anchored by
welding to the opposite side and rear end of the next interior boom
section, see FIGS. 16 and 19. The retainer means 45 for wear pads
40 and 41 includes shoe elements 46 which rest rockably on the
bearing bars 43. As best indicated in FIG. 19 the wear pad retainer
means 45 is effectively located in an opening in the top wall of
the next interior boom section 26 or 27 and fore and aft stop
elements 47 and 48 on such top walls limit the pivoting movement of
the rear upper wear pads 40 and 41. The rear upper wear pad 42 of
fly section 28 may be a non-pivoting wear pad having a low friction
facing element 49 as indicated in FIG. 12.
The inner and outer mid-sections 26 and 27, FIG. 13, are also
equipped at their forward ends and bottoms with the wear pads 38
and retainer means held within the bottom section 37 of reinforcing
collar 36 substantially as described previously for the base
section 25. Additionally, lateral stability and guidance between
the telescoping boom sections is achieved near the forward ends
thereof by side lateral guidance elements 50 on the boom sections
25, 26 and 27, FIG. 14. Toward their rear ends, the moveable
telescoping boom sections are further equipped near and above their
bottoms with side wear pads 51 which further guide and stabilize
the boom sections laterally.
As previously discussed, the essence of the present invention
resides in the arrangement and mounting of the hydraulic rams which
impart movement to the telescoping boom sections. A first ram 52,
FIG. 12, has its cylinder portion 53 arranged forwardly and its rod
portion 54 extending rearwardly, and this is the reverse of the
conventional arrangement for crane boom rams. The cylinder portion
53 of the ram 52, FIG. 16, carries side trunnions 55 which are
pivotally received by bearing plates 56, carried by a rigid support
frame 57 provided in the rear end portion of inner mid-section
26.
The rear end of rod portion 54 of ram 52 is pivotally secured to
the base section 25 in the following manner shown particularly in
FIGS. 12, 17 and 18. In these figures a rear supporting frame 58
including space vertical walls 59 is secured fixedly in the rear
end of base section 25. The vertical walls 59 have openings 60
which receive vertical guide elements 61 for ball roller bearings
62. The outer races of the ball bearings 62 engage moveably for
rolling action in vertically elongated guide slots 63 in the
elements 61. The ball bearings are cushioned in their vertical
rolling movement by top and bottom opposing springs 64 engaging
over top and bottom pin extensions 65 on the shoe elements 64'
which are in sliding contact with the outer races of the roller
bearings 62. The inner races of ball bearings 62 receive shafts 66,
FIG. 17, having threaded engagement within openings of a sturdy
cross sleeve 67 and rigid therewith thus providing rotative
movement between the sleeve 67 and the outer rolls of the ball
roller bearings 62. A cylindrical bushing 68 engages rotatably over
the sleeve 67 and includes end flange plates 69 rigid therewith
which cover the interior sides of the slots 63. These elements in
FIGS. 17 and 18 constitute the floating or self adjusted cushioned
pivotal connection between the rod portion 54 of ram 52 and the
relatively stationary base section 25 of the crane boom. The
springs 64 are sized to carry the weight of the rod and normally
keep it centered in slot 63. When the rod is stressed during
extension or retraction or due to misalignment caused by wear in
the boom, during extension and retraction the rod is free to move
slightly up or down to relieve the stress or to prevent binding.
Removable cover plates 70 are provided on the vertical walls 59 to
retain and enclose the bearings 62 and associated parts. It may be
observed in FIGS. 12 and 13 that the cylinder 53 of ram 52 extends
forwardly of the trunnions 55 and is cantilevered forwardly of this
point. Means yet to be described are provided on the forward
extremity of the ram 52 to support and stabilize the cantilevered
cylinder 53. Extension and retraction of the ram 52 serves to
extend and retract the inner mid-section 26 relative to base
section 25 when conventional controls on the crane are
utilized.
A second ram 71 interconnects the rear end of inner mid-section 26
with outer mid-section 27. This second ram is conventionally
arranged in that its cylinder portion 72 is rearmost and its rod 73
extends forwardly. The rear end of cylinder 72 is pivotally secured
at 74 on the same rigid frame 57 which supports the trunnions 55,
FIG. 16. The ram 71 extends forwardly through a box or core member
75 whose rear end is equipped with side trunnions 76 pivotally
supported in sleeves 77, in turn rigidly held in braces 78, FIG.
15, on the rear end and bottom of outer mid-section 27. The rod 73
of ram 71 has its forward end pivotally secured at 79 to the
forward end of box or core member 75. Thus when ram 71 is extended
the forward movement of piston rod 73 will correspondingly move the
box or core 75 which is tied pivotally to the rear end of outer
mid-section 27 through trunnions 76, and the outer mid-section can
therefore be extended or retracted relative to the inner
mid-section 26 at the will of the operator since the several
hydraulic rams of the boom are separately supported and
independently operable through the use of conventional controls in
the cab of the crane.
As previously suggested the forward cantilevered end of cylinder 53
is stabilized and supported. An extension 80 projects from the
forward end of cylinder 53 and has secured to it a bracket
structure 81, FIG. 14, said bracket structure overlying the top
wall of box or core 75 and having a wear pad 82 slidably bearing
thereon. Side stabilizing guide shoes 83 on the bracket 81 engaged
beneath top flanges 84 on the core 75 and engage closely outside of
the core sidewalls. Thus, when there is relative movement between
the box or core 75 and the cylinder 53 of ram 52 caused by
extension or retraction of ram 71 the wear pad 82 will slide over
the top wall of core 75 and support the forward end of cylinder 53
at all times. The shoes 83 will guide and stabilize the
cantilevered cylinder 53 of ram 52 laterally at all times. The box
or core 75 is similarly supported and carries a wear pad 93 on its
bottom at its forward end engaging slidably upon the inner surface
of the bottom wall of fly section 28.
A third hydraulic ram 85 interconnects the rear end of outer
mid-section 27 with the forward end portion of fly section 28. This
third ram is conventionally installed with its cylinder 86 rearmost
and its rod 87 forwardmost. The forward end of the rod 87 is
pivoted at 88 to the fly section 28 above the transverse web 39
thereof. The rear end of cylinder 86 is similarly pivoted as at 89
to the rear end of outer mid-section 27, which mid-section, FIG.
15, is equipped with sleeve elements 90 to receive the pivot
element 89 or pin. The front end and bottom of cylinder 86 has a
wear pad 92 secured to it and slidably engaging the top of the web
39 of fly section 28 to support the ram 85 when it is extended.
Consequently extension or retraction of the third ram 85 will
produce corresponding movement of the fly section 28 relative to
outer mid-section 27. As indicated in FIG. 13 the forward end of
fly section 28 carries the usual boom nose assembly 91.
The means for extending or retracting independently and selectively
the three boom sections 26, 27 and 28 relative to the base section
25 in any sequence or order have now been described in connection
with the three rams 52, 71 and 85. The disclosed arrangement
renders it practical to place all three hydraulic rams bodily
inside of the boom fly section 28, whereby the same in effect can
telescope over the three rams when retracted, FIG. 12. The use of
the core or box 75 in conjunction with the ram 71 and the
arrangement of the cylinder 53 of ram 52 forwardly with the rod
portion 54 rearmost allows the use throughout the boom of single
cylinder-piston hydraulic rams instead of rams containing multiple
piston and cylinder sections, the latter being more complicated and
costly and also having a much greater tendency to leak because of
sagging when extended. The provision of the cushioned vertically
shiftable pivot for the rear facing piston rod 54 of cantilever ram
52 and the additional pivoting at 55 of the cylinder 53 plus the
supporting of the forward end of this cylinder by the bracket
structure 81 and wear pad 82 and associated elements greatly
relieves the ram 52 from bending stresses which could be imparted
thereto by the flexure of the boom under load and cocking of the
boom sections when they are extended as the distance between their
upper and lower wear pads is greatly lessened.
Most importantly the ability to mount the three single piston rams
compactly inside of the fly section 28 allows the several sections
of the boom to approach uniform height in cross-section as best
depicted in FIG. 14. This is in contrast to the prior art where
there must be a considerable space between the top wall of the base
section and the next innermost section of the telescoping boom, as
discussed previously. By virtue of the invention a much stiffer
boom can be constructed from a given amount of metal and economy of
materials is obtained while actually increasing the efficiency of
operation of the boom.
The ram arrangement whereby the retracted fly section 28 may
telescope over all three rams is rendered possible by having the
three rams individually and separately supported. That is to say,
no one hydraulic ram is secured to or supported by another ram.
The terms and expressions which have been employed herein are used
as terms of description and not of limitation, and there is no
intention, in the use of such terms and expressions, of excluding
any equivalents of the features shown and described or portions
thereof but it is recognized that various modifications are
possible within the scope of the invention claimed.
* * * * *