Joints and connections – Articulated members – Lockable at fixed position
Reexamination Certificate
2001-04-18
2003-08-05
Novosad, Christopher J. (Department: 3671)
Joints and connections
Articulated members
Lockable at fixed position
C403S337000, C403S338000, C403S344000, C403SDIG009
Reexamination Certificate
active
06602016
ABSTRACT:
BACKGROUND OF THE INVENTION
a. Field of the Invention
The present invention relates generally to hydraulic systems used in heavy equipment and the like, and, more particularly, to a clamp assembly for mounting hydraulic lines to the booms and arms of heavy equipment and similar structures.
b. Related Art
Hydraulic lines are commonly employed to supply hydraulic oil to actuators that operate the various components of heavy equipment and similar apparatus. For example, such lines are commonly used to supply oil to hydraulic cylinders and rams for operating various parts and systems on earth-moving and land-clearing equipment. Typically, the hydraulic lines are constructed of lengths of rigid steel tubing that are joined by hoses where flexible connections are required.
For example,
FIG. 1
shows an exemplary articulated excavator arm
10
having a bucket
12
mounted on its outer end. The bucket is provided with a “thumb” attachment
14
which is operated by a hydraulic cylinder
16
. Hydraulic pressure is applied to the cylinder from a remote source (e.g., hydraulic pump mounted on a main chassis) via rigid hydraulic lines
20
and flexible hoses
22
.
As can be seen in
FIG. 1
, the rigid hydraulic lines
20
are secured to the segments
24
,
26
of the articulated arm by mounting clamps
28
. It is important for the clamps to hold the lines tightly to the arm, in order to prevent the lines from hanging loose and becoming caught on external objects or otherwise being damaged during use. Furthermore, the clamps must hold the hydraulic lines against longitudinal movement in order to prevent the lines from “creeping” and working loose in response to internal pressure changes.
In some original equipment manufacturer (OEM) installations, these problems are dealt with using a mounting structure that is welded to the support boom and sometimes directly to the hydraulic line itself. In other installations, however, there is a need for a device for detachably mounting the hydraulic lines to the support structure, or for subsequently attaching one or more additional lines in a convenient and secure manner. This is especially true in the case of after-market attachment that are added to existing equipment, such as the thumb attachment
14
which is shown in
FIG. 1
, for example.
One type of device which is used for this purpose is a bolt-on clamp assembly, which has the advantage of relatively easy installation and/or removable. Moreover, the bolt-on clamp assemblies can often be used to “piggy back” on existing OEM mounts: the original mounting bolt is removed and the after-market clamp is placed on top of the OEM bracket or clamp, and then a new, longer bolt is passed through both clamps to secure the assembly to the support structure.
While advantageous for the reasons described above, prior forms of bolt-on clamp assemblies have generally been less than satisfactory in one respect or another. To illustrate this,
FIGS. 2A-2B
show a prior art clamp assembly
30
, of a type that is used by several manufacturers. As can be seen, the clamp assembly includes upper and lower members
32
,
34
, which are typically formed of ordinary cast steel. The clamp members are mounted to the underlying support structure
36
by a bolt
40
that passes through corresponding bores
42
,
44
and is threaded into a cooperating bore in the underlying structure. Upper and lower generally concave jaw portions
46
,
48
are located to one side of the bolt and are configured for receiving a rigid hydraulic line
50
having a corresponding diameter. On the opposite side of the mounting bolt, the edge of the upper member extends downwardly to form a pointed flange
52
which bears against the upper surface
54
of the lower clamp member so as to form a fulcrum
56
. Thus, as bolt
40
is tightened, the downward pressure which is inserted by the head of the bolt against the upper surface
58
of the upper clamp member
32
causes the jaw portion
46
to pivot downwardly in the direction indicated by arrow
60
, thus exerting a clamping force against hydraulic line
50
.
One deficiency of clamps of the type shown in
FIGS. 2A-2B
is that the location of the bolt between the fulcrum and the jaw portions results in a reduced mechanical advantage, i.e., the grip force which is exerted at the jaw portions is actually less than that which is exerted by the bolt against the clamp members. This type of clamp is also cumbersome and difficult to use, being that the upper and lower members tend to twist relative to one another until they move into engagement with the hydraulic line, so that the assembly tends to “flop” about and become misaligned during installation.
Perhaps more seriously, the jaw portions of such clamps tend to deform and crush the hydraulic line as the assembly is tightened, which is undesirable from the standpoint of reducing flow and compromising the structural integrity of the line, amongst other reasons. This problem is compounded by the fact that the jaw portions, with their pincer-like movement, are only able to engage limited areas along the top and bottom of the hydraulic line, which impairs their ability to establish frictional engagement with the line; as was noted above, it is important for the clamp to hold the hydraulic line against longitudinal “creeping” motion, as well as against motion in lateral directions. As a result, the tendency is for the operator to tighten the bolt even further in an effort to stop longitudinal movement of the hydraulic line, thereby increasing the deformation and damage to the line.
In some instances, manufacturers have resorted to the expedient of installing a plastic or rubber insert between the jaws in an effort to reduce damage to the hydraulic lines. Unfortunately, the inserts tend to slip against the hydraulic lines, with the result that longitudinal movement/creep of the lines increases unacceptably. Furthermore, the plastic/rubber inserts tend to melt when subjected to the high temperatures that hydraulic lines develop in many types of machinery.
Accordingly, there exists a need for a bolt-on clamp assembly for mounting hydraulic lines to a support structure that establishes a firm grip against the hydraulic line without causing deformation or crushing of the line. Furthermore, there exists a need for such a clamp assembly that avoids deformation/crushing of hydraulic lines without need for an elastomeric or deformable insert. Still further, there exists a need for such a clamp assembly that establishes a firm frictional engagement with hydraulic lines so as to prevent longitudinal movement of the lines relative thereto. Still further, there exists a need for such a clamp assembly that is mechanically efficient so as to avoid the need for over-tightening the mounting bolt which secures the assembly to the support structure. Still further, there exists a need for such a clamp assembly in which the clamp members thereof are linked in stable relationship with respect to one another so as to avoid twisting and/or misalignment during installation.
SUMMARY OF THE INVENTION
The present invention has solved the problems cited above, and is a bolt-on clamp assembly for mounting a hydraulic line to a support structure.
Broadly, the clamp assembly comprises upper and lower clamp members, the upper clamp member having a downwardly facing jaw portion and the lower clamp member having an upwardly facing jaw portion, so that the jaw portions define a receiving area for engaging a hydraulic line therein; a mounting portion located to one side of the receiving area for passage of a mounting bolt therethrough; and a hinge structure interconnecting the upper and lower clamp members so as to form an upwardly-directed fulcrum on a side of the receiving area opposite the mounting portion, so that the upper clamp member pivots about the upwardly-directed fulcrum in response to tightening of the mounting bolt so as to exert a downwardly directed clamping force against the hydraulic line in the receiving area.
The hinge structure interconnecting the upper and lower clamp
Eckart Dennis D.
Keddie Lee D.
Hathaway Todd N.
HKX Inc.
Novosad Christopher J.
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