Note: Descriptions are shown in the official language in which they were submitted.
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BACI~GROUND OF T~ INVENTION
1 Field of the Invention
This invention concerns presses and more particularly
presses having a ram which is mounted for swinging movement,
such as is used in cutoff apparatus for severing lengths of ~;
elongated stock emanating from a tubing mill or other such
source. '
2. Description of the Prior Art ~;
In the past, presses have incorporated rams operated ~ ~
by power cylinders, such as large diameter air cylinders. In ' '
these arrangements typically the ram would be mounted to the
output member of the power cylinder, and the air cylinder would
be stroked against the bias of return springs. The application
of such cylinder-operated presses to tubing or other elongated
stock cutoff apparatus has been limited for several reasons to
relatively light duty situations. Firstly, the ram mechanism,
if mounted directly to the output piston of the power cylinder ~ ~ `
has been limited in size by the size of the power cylinders,
since the ram was typically guided in its stroke by the cylinder
structure, or else additional ways or slides were by necessity
required. Since the cost of power cylinders increases dispro-
portionately with increasing cylinder bore size, it has been
found to be economically unfeasible to operate rams over a cer-
tain size by means of air cylinders. In addition, the typical
arrangement of stroking the press against the bias of return
springs has the disadvantage that the available force of which ;~
the ram would be capable of exerting would be proportionately ~
reduced as the return springs were compressed. This disadvantage '
is aggravated in the usual'situation in which maximum ~orce is
required at the extreme position of the ram, and necessitates
substantially increased cylinder size and/or operating pressure
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requirements to obtain force levels adequate to operate
the cutoff die s0t.
In other contexts, power cylinders have been
coupled with force-multiplying mechanisms, such as toggle
link mechanism and the ram stroked vertically upward to -
obviate the need for return springs or double acting
cylinders. However the weight of the ram in this design `
would also act to reduce the available force exerted by the
ram as the ram was stroked by the power cylinder. In addi-
tion the cylinder controls tended to be rather complex and
subject to the burdensome maintenance requirements, since
the cylinder would be depressurized and the return springs
or ram weight utilized to return the ram to its initial
position.
In some applications, the timing of the press
operation is critical, as in those cutoff press apparatuses
involving cutting on the fly or cutting of the stock as it
rapidly emanates from a stock production mill, such as a
tubing or extrusion mill, in which the entire cycle must of ~ ~ -
necessity be carried out with relatively precise timing. These
design problems have limited the application of such c~linder-
operated presses to the aorementioned stock cutoEE applications.
In such apparatus, it has been the practice to provide
a swinging ram type press in which a ram member has been sup-
ported on a pair of pivotal links which constrain the ram move-
mentto that of a swinging motion about the pivotal support of
the links, its pivotal movement producing both translation in
the direction of the movement of the stock, as well as a
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reciprocation thereof of the ram transverse to the direction of
movement of the stock. A typical example of such a press is
disclosed in U. S. Patent No. 3,288,011. In this design, the
ram is driven so as to be swung or oscillated about these
pivotally supported links by means of a crank mechanism driven ;
by an electric motor and clutch, the crank mechanism being con-
nected to the connecting rod to the ram to induce the swinging
movement. The weight of the ram acts in concurrence with the
downward and forward movement of the ram induced during the ram
stroking in a forward direction, with the geometry of the links,
etc~ producing the full stroking of the ram without the need
for reversal of the electric motor or precise control over the
crank mechanism or electric motor and clutch.
The swinging movement of the ram in turn produces
operation of the cutoff die set which is adapted to be recipro-
cated by the ram as it travels with the stock on an upper rail
set carried by the ram and a lower rail set fixed to the machine
base. The cutoff die set, as described in the aforementioned
U. S. patent, includes means for initially clamping the die set
to the stock to be severed, causing the die set to traverse the
rail set together with the stock. Subsequently, downward move-
ment of a cutoff blade, included in the die set is induced by
the downward movement of the ram moving through its arcuate path
as it swings about the pivotal supports provided by the pivotal
links. Continued rotation of the eccentric crank drives the
ram to its full down position with further rotation producing a
reversal of movement of the swinging ram, to first withdraw the
cutoff blade, then releasing the stock from the die set to allow
it to be returned to its initial pOsitiQn by means of a return
cylinder or other mechanism prior to initiation of a new cycle.
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.:
A variation of the basic mechanism provides for an adjustable `
length connecting rod which serves to provide a capability for
shifting the segment o the arcuate path through which the ram is
constrained to move by virtue of its support on the pivotally
supported links, which shifting provides for adjusting the shut
height or the position of the ram in its full down position, as
well as the length of its stroke in such a way as to adapt the
cutoff apparatus to die sets of varying configurations, to accommo-
date its application to varying tube sizes etc.
While these machines have performed very satisfactorily
and are adapted to reliably stroke the ram through its required
swinging movement, the electric motor, clutch, and eccentric
crank components comprise a considerable element of manufacturing
cost in the apparatus.
On the other hand, while the aforementioned cylinder-
operated presses suffer from the disadvantages described, they
do exibit the inherent advantage of a generally lower manufac-
turing costs, due to the use of simple power cylinders as a
source of operating means for the ram where cylinders of a
reasonable size are able to be utilized.
Accordinglyr it is an object of the present invention
to adapt a power cylinder to a swinging ram cutoff press of the
sort described.
It is a further object of the present invention to
adapt such power cylinder to the cutoff mechanism described in
such a way as to not necessitate the use of complex controls or
adversely affecting the reliability of the machine.
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:~0~399~9
~.
It is yet another object of the present invention to ;
provide such an adaptation which does not involve the use of
return springs tending to reduce the available force generated
by the cylinder during stroking of the ram.
It is a further object of the present invention to
incorporate a power cylinder operating device into a swinging -
ram type cutoff apparatus in such a way as to enhance the
available force at that portion of the ram's stroke requiring
maximum force to be exerted by the ram.
It is yet another object of the present invention to
provide such an adaptation without entailing the incorporation
of expensive and precision structural or control components.
SUMMARY OF THE INVENTION
These and other objects which will become apparent
upon reading of the following Specification and Claims are accom-
plished by incorporating a power cylinder into a swinging ram
press by providing a toggle link pivotally connected at one end
to a connecting rod link, in turn pivotally connected to the
ram, with the power cylinder pinned to the connected ends of
the toggle link and connecting rod so as to act as a toggle
mechanism upon stroking of the power cylinder. The relative
geometry of the ram supporting links, the toggle link, the
connecting rod link and the power cylinder is such that the
toggle mechanism is at the extreme, advanced position of the
ram, and the power cylinder executes its full oscillation of
the ram upon a stroke in either direction to obviate the need
for a reversal of the cylinder-operating member during the
stroking of the ram. The connecting rod link is adjustable in
length to provide a capability for adapting the cutoff apparatus
to varying shut height and stroke requirements of differing die
set sizes and configurations.
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BRIEF DESCRIPTION OF THE D~WINGS
FIGURE 1 is a ~ront elevational view of a swinging -
ram cutoff press, according to the present inv~ntion.
FIGURE 2 is a side elevational view of the swinging
ram cutoff press, shown in FIGURE 1.
FIGURE 3 is a view of the Section 3-3, taken in
FIGURE 1.
FIGURE 4 is a view of the Section 4-4, taken in
FIGURE 1.
FIGURE 5 is a diagrammatic view of the swinging ram
cutoff press, shown in FIGURE 1, in an advanced position of
the swinging ram.
FIGURE 6 is a diagrammatic representation of the
swinging ram, shown in FIGURES 1 through 5, w:ith the swinging
ram elevated by retraction of the power cylinder.
FIGURE 7 is a diagrammatic representation of the
swinging ram cutof press, shown in YIGURES 1 through 6, with
an adjustment of the length of the connecting rod link to pro-
duce a longer stroke, greater shut height stroking of the
swinging ram.
DETAI~ED DESCRIPTION
In the following detailed description certain specific
terminology will be utilized for the sake of clarity and a parti-
cular embodiment described, but it is to be understood that the
same is not intended to be limiting and, indeed, should not be
so construed, inasmuch as the invention is capable of considerable
variation within the scope of the appended claims.
Reerring to the drawings, and particula~l~ FIGURES 1
through 4, the swinging ram cutoff apparatus 10, according to
the present invention, is depicted. The cutoff apparatus 10
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includes base support means 12 including a lower housing 14 and
an upper housing 16, each comprised of a steel weldment. Sup-
ported on the upper housing 16 for swinging movement is a die
set operating ram 18, the means providing the pivotal support :
being provided by a pair of pivotal links 20 and 22 pinned at
one end to the upper housing 16 and at the other to the ram 18.
This mode of support serves to constrain the ram to swinging
movement through an arcuate path.
This swinging movement is adapted to operate a die ~ :
set 24 which is retained between an upper rail set 26 affixed ~.
to the lower surface of the ram 18 and a lower rail set 28
affixed to the lower housing 14 by means of an upper die set
carriage 30 and a lower die set carriage 32, as shown in FIGURES
1 and 2. The descending movement of the ram 18 created by its
swinging motion reduces the clearance between the upper rail set
26 and lower rail set 28 which movement induces operation of the ~"
cutoff die set 24. This operation includes a movement of a pair
of clamping jaws 34 and 36 upon initial downward movement of the :
ram 18 to clamp the die set 24 to the work W passing through the
clearance space between the upper rail set 26 and the lower rail
set 28, clutching the die set 24 to the workpiece W so as to
cause it to move together therewith along the upper rail set 26
and the lower rail set 2~.
Further downward movement of the ram 18 occurring as i~
its swinging motion progresses causes operation of the cutoff
blade 38 causing the severing of the work W within the die set
24. Upon reversal of movement of the ram 18, the cutoff blade :~:
38 is initially withdrawn, then the clamping jaws 34 and 36 are
operated to release the work W, all of this taking place before
the die set 24 has reached its limit of travel on the upper rail
set 26 and lower rail set 28. Upon release of the clamping jaws
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34 and 36 a return cylinder, not shown, returns the die set 24
to its initial position, as shown in FIGURE 1.
Since this aspect of the cutoff press per se does not
comprise the present invention and inasmuch as the details of
the same are now very well known to those skilled in the art,
the specific design of the die set 24 and other structural de-
tails relating thereto are not here disclosed.
A pair of baffles 40 and 42 are typically provided to
collect the cutoff slugs caused by shearing of the workpiece W,
which may be collected into a bin, not shown, disposed within a
cutout opening 44 in the front plate of the lower housing 14.
The links 20 and 22, as noted above, are pivotally
supported on the upper housing 16 and also pivotally connected
to the ram 18. FIGURE 4 depicts in some detail the nature of
these pivotal connections, with the connection of link 22 de-
picted as typical. Each of the links 20 and 22 are bifurcated
into arms 48 and 50 to form a clevis at its lower end, receiving
a pivot pin 46 passing through each arm 48 and 50 of the link 22
and also through a bore 52 formed in the ram 18. A pair of
needle bearings 54 and 56 are provided to provide a rotatable
support for the pivot pin 46 within the bore 52, with a spacer
sleeve 58 provided to maintain the separation of needle bearings
54 and 56. A pair of thrust washers 60 and 62 are also included.
The link 22 is pivotally supported at its other end within the
upper housing 16 between a pair of end plates 62 and 64 forming
part of the weldment of which the upper housing 16 is constituted,
by means of a pivot pin 65 having end portions 66 and 68 disposed
and retained between the end plates 62 and 64 with a central
portion 70 passing through a bore 72 formed in the link end
portion 74 joining the bifurcations 48 and 50.
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A pair of needle bearings 76 and 78 are provided,
maintained in axial position by means of a spacer sleeve 80.
Thrust bearings 82 and 84 are also provided cooperating respec~
tively with a boss portion 85 welded to end plate 62 and a
shoulder formed by the enlarged diameter end portion 68 of the
connecting pivot pin 70. A boss portion 87 is also provided
receiving the end portion 68, as shown.
Lubrication fittings 86 and ~8 may be provided in
order to supply lube passages 90 and 92 formed internally in
the pin 46 and 70, respectively. Suitable retainers 94, 96, 98
and 100 are provided to provide endwise or axial retention of
the pivot pins 46 and 70, respectively, with the lube fittings
86 and 88 and cap screws 102 and 104 being provided to secure
the respective retainers 94, 96, 98 and 100 to the link 22 and
the upper housing 16, respectively.
The ram operating mechanism which is adapted to oscil-
late the ram through its swinging movement in the arcuate path
through which it is constrained to move by the links 20 and 22,
includes a toggle link 106, a connecting rod link 108 and an
operating cylinder assembly 110. The toggle link 106 is mounted
at one end to the upper housing 16 in a similar Eashion as the
links 20 and 22 by the journaling of a end section 109 in the
side plates 62 and 64 included the upper housing 16 weldment.
The toggle link 106 has bifurcated portions 111 and 112 which
act as a clevis for a master pivot pin 114 retained in the outer
end of bifurcations 111 and 112 by means of retainer plates 115
and 116 retained by cap screws 118 at one end and a lube fitting
120 at the other end in similar fashion to the other pivotal
connections, described above.
Master pivot pin 114 has journaled thereon one end of
the connecting rod 108. The connecting rod 108 is formed as two
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9~9 ~
end portions 124 and 126 joined by an oppositely threaded
adjusting rod 128 threadably received within bores 130 and 132
formed in the respective connecting rod ends 124 and 126. The
threaded adjusting rod 128 having a central wrenching portion .
130 so as to enable the threaded rod to be rotated to vary the
effective length of the connecting rod 108. The upper end 124,
as noted, is journalled on the master pivot pin 114, as shown,
with bearing 134 provided and thrust spacers 136 and 138, in-
termediate the clevis 141 end portions 140 and 142 of the oper- :
ating cylinder assembly 110, to be described further herein.
The clevis portions 140 and 142 are similarly journalled by
means of rotary bearings 144 and 146 receiving the master pivot
pin 114 with thrust spacers 148 and 150 provided intermediate
the bifurcations 110 and 112 of the toggle link 106 and the
clevis portions 140 and 142 of the operating cylinder assembly
110. , .
The lower connecting rod end 126 is journalled within
an opening 150 provided in the ram 18 in the region whereat a
pivot pin 152 associated with the front pivotal link 20 is con-
nected to the ram 18 so that the connecting rod 126 is also
journalled on the pivot pin 152 as provides the pivotal support
for the link 20. A needle bearing 154 is provided while separate
bearings 156 and 158 are provided in appropriate openings in the '
bores in the ram 18 to provide a rotatable support of the ram 18
on the pivot pin 152. Retainer thrust bearings 160 and 162 are
also provided to maintain the proper spacing between the ram 18
and bifurcated portions 164 and 166 of the pivot link 20. Cap
screws 168 cooperating with a retainer plate 170 and a lube
fitting 172 cooperating with a retainer plate 174 serves to
retain the pivot pin 152 in the assemblage.
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The power cylinder assembly 110 includes a power
cylinder body 176 pivotally mounted at its rear portion by
means of a pivot pin 178 passing through an opening 180 formed
in a mounting plate 182 affixed to the rear of the power cylin-
der body 176. The pivot pin 178 is retained in a pair of clevis ~
plates 184 and 186 welded to a mounting bracket 188 secured to ~ -
the upper housing 16, as shown in FIGURES 1 and 2. ;
The power cylinder assembly 110 also includes an -
operating rod 192 connected to a clevis end portions 140, 142.
In operation, the cylinder assembly 110 is in an
initial position, either with the operating rod 192 in the
fully retracted position, as shown in FIGURE 1, or fully extended
position, as shown in FIGURE 6 in schematic form. ~n either
the fully retracted or extended position, the ram 18 is in the
full up position, with the toggle link 106 and connecting rod
108 askew, as shown in FIGURES 1 or 6. By initiation of a
cutoff cycle, the cylinder assembly 110 is pressurized by means
of solenoid control val~res, not shown, to cause the operating
rod 192 to be retracted~ or extended. The toggle link 106 and
connecting rod link 108 are drawn into the aligned position, as
shown in FIGURE 1, with an incraasing mechanical advantage
characteristic of toggle mechanisms being imposed on the ram 18
through the connecting rod 108. A maximum mechanical advan-
tage is achieved in the ull down position o the ram 18 as de-
picted in FIGURE 1, since the operating rod extends trans-
versely to the aligned toggle link 106 and connecting rod link
108 and generally transversely to the pivotal links 20 and 22.
Continued movement of the operating rod 192 again produces ele-
vation of the ram 18 so that in the fully retracted or extended
position, the ram 18 has again returned to the initial or up
position. It must be seen that the power cylinder 110 need not
be reversed during the cycling of the cutoff press, but in a
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single stroke produces both the down and up movement of the ram.
Furthermore, the mechanical advantage is at a maximum when the
force requirements are at a maximum, i.e., at the ram full down
position. It should also be noted that the ram 18 weight does
not work in opposition to the force applied by the power cylin-
der assembly 110 to further maximize the force able to be
exerted by the power cylinder assembly 110 to the ram 18.
The adjustment of the connecting rod 108 produces a
very advantageous flexibility in the application of any given
press, since the shut height and stroke may be varied by means
of the adjustability in length of the connecting rod 108. This
can be seen by ~he schematic representation of FIGURE 7 showing
the adjustment rod 128 threaded fully into the connecting rod
ends 124, 126 to reduce the connecting rod 108 length to a minimum.
This produces an increased stroke, but instead o~ reducing the shut
height, the shut height is increased, as shown in FIGURES 5 and 7.
The power cylinder assembly may be provided by an air
cylinder, since the output requirements are reduced to a minimum
by the disclosed arrangement, although hydraulic cylinders alter-
natively could be used if desired. In addition the power cylin-
der assembly 110 would normally include means for controlling
decelerati~on to control bounce at the end of the retraction or
extension of the operating rod 192, but, since such devices are
well known in the art, and many suitable designs are available,
this device is not here described.
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