Information
-
Patent Grant
-
6772682
-
Patent Number
6,772,682
-
Date Filed
Thursday, February 13, 200321 years ago
-
Date Issued
Tuesday, August 10, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Ostrager; Allen
- Self; Shelley
Agents
-
CPC
-
US Classifications
Field of Search
US
- 100 99
- 100 214
- 100 25
- 100 7
- 100 258 R
- 100 347
- 072 211
- 072 446
- 072 448
- 072 455
- 072 456
-
International Classifications
-
Abstract
A shutheight adjustment system incorporating tie rods and accompanying hydraulic tie rod nut assemblies in connecting a bed to a bolster of a mechanical press for dynamically altering the tensioning of the tie rods. Each hydraulic tie rod nut assembly includes a cylinder with an inner sliding piston threadably engaging the tie rod. A pressurizing mechanism injects pressurized fluid within a chamber formed by the piston and cylinder. By increasing pressure within the chamber of the hydraulic tie rod nut assembly, compression between the press bed and press bolster may be increased, thereby increasing the press shutheight.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to mechanical presses and, in particular, to a shutheight adjustment mechanism utilizing a bolster hydraulic tie rod assembly to change press shutheight while the press is operating.
2. Description of the Related Art
Mechanical presses, for example, stamping presses and drawing presses, include a frame having a crown and bed with a slide supported within the frame for motion toward and away from the bed. The slide is driven by a crankshaft having a connecting arm connected to the slide. Such mechanical presses are widely used for stamping and drawing operations and vary substantially in size and available tonnage depending upon the intended use.
In prior art presses of this type, the slide is generally connected to the crankshaft by a connection mechanism rod which is adjustable in length. The connecting rod is attached to another member that is adjustable in its relation to the slide so that the shutheight opening between the slide and the bed can be adjusted to accommodate various die sets. A normal slide adjustment mechanism adjusts the slide to a predetermined operating shutheight. Alternatively, the bed portion or bolster of the press may have its position adjusted relative to the slide so as to adjust the shutheight therebetween, as disclosed in U.S. Pat. No. 3,858,432. Regardless of the mode of shutheight adjustment, the slide is generally guided on the uprights of the press frame extending between the crown and the bed so that the parts of the die set remain in precise registration as the slide reciprocates.
A prior art patent, U.S. Pat. No. 4,502,379, shows a press in which shutheight is controlled by adjustment members located between the press crown and bed. Expansion and contraction of the adjustment members was accomplished by supplying hydraulic fluid into the members and thereby changing shutheight.
Another example of press shutheight control is described in U.S. Pat. No. 4,939,918, in which a fluid chamber beneath the lower press die is filled with pressurized oil to cause changes in press shutheight or load.
In mechanical presses utilized in stamping staked laminations, for example, there is a need to maintain shutheight tolerances to within 0.001 to 0.002 inches. Staked laminations are normally utilized in construction of the stator or rotor cores of electric motors. These laminations need precisely stamped surfaces to allow the laminations to be press fit together. Control of press shutheight is also necessary to maintain accurate part tolerances and prolong die life. A particular problem with punch presses is that the press shutheight normally varies with changes in press speed and thermal changes in the press itself.
The present invention is directed to fill the needs and overcome the aforementioned problems associated with mechanical press shutheight adjustment mechanisms wherein it is desired to accurately control shutheight while the press is in operation by controlling the connecting force on the press tie rods.
SUMMARY OF THE INVENTION
The present invention provides an adaptable feedback shutheight system capable of automatically changing the shutheight to compensate for various press conditions.
Generally the invention provides a bolster hydraulic tie rod nut assembly connected to a feedback system that automatically changes press shutheight to compensate for various press changes. The hydraulic tie rod nut is constructed to vary the connecting force between the bolster and the bed applied therebetween in response to changes in an applied hydraulic fluid. While monitoring the press shutheight, the feedback control system changes the pressure communicated to the expandable tie rod nut assemblies, thereby changing the amount of compression between the bed and bolster combination and ultimately press shutheight. Crown movement can be effected in a similar fashion (as set forth in U.S. Pat. 5,285,722 and incorporated by reference herein), permitting yet a further mode of controlling press shutheight.
An advantage of the hydraulic tie rod assembly is that by incorporating the tie rod nut assembly with the monitoring of the shutheight, a feedback system is created to automatically change the hydraulic pressure to the tie rod nut assemblies.
Another advantage of the present invention is that the tie rod nut assembly with its associated feedback system can maintain the press shutheight to within 0.001 inches to 0.002 inches under changing press operating conditions. Further, press shutheight is dynamically controlled while the press is cycling.
An additional advantage of the shutheight adjustment apparatus of the present invention is that the tie rod assembly may be installed easily without any major changes to the press slide drive system.
A further advantage of the shutheight hydraulic tie rod assembly system is that it is possible to retrofit existing presses with the new system for more accurate shutheight adjustment and control.
An even further advantage of the tie rod assembly, being mounted to couple the bed and bolster together, is that the hydraulic tie rod nut assembly, whether mounted adjacent the bed or the bolster, is in an accessible yet generally protected position within the machine press.
A further advantage associated with having a plurality hydraulic tie rod nut assemblies associated with the bolster and bed is that, due to their relative proximity to the press shutheight region, the plurality of hydraulic tie nut assemblies can be more readily used to adjust for variances in shutheight that may occur across the width of the press.
Yet another advantage of the present invention is that it is still possible to preload the press. Preloading the press structure eliminates clearances between press parts, thereby making the press more dimensionally stable.
The invention, in one form thereof, comprises a press in which a crown and bed are attached together by a frame. A slide is attached to the crown for reciprocating movement in opposed relationship to a bolster mounted upon the bed. A plurality of tie rods connect between the bolster and the bed onto which are attached a plurality of pressure-activated tie rod nut assemblies associated with the bed and bolster, so that when activated, the nut assemblies can be used to force the bolster and bed toward one another in order to increase shutheight. A feedback means is connected to a shutheight measuring means and to the tie rod nut assemblies for comparing a predetermined desired shutheight to a measured shutheight. The feedback means activates the tie rod nut assemblies when the measured shutheight deviates from the predetermined shutheight.
A pressure-activated tie rod nut assembly includes a cylinder block having a cylinder bore fit about a tie rod. A piston is threadedly engaged about the tie rod and slidingly disposed within the cylinder bore thereby forming an inner chamber. A tie rod nut is threadably engaged about the tie rod, engaging the piston, so that when the inner chamber is pressurized with a fluid or liquid, the increase in pressure forces the piston and tie rod nut away from the cylinder block, thereby effectively forcing the bed and bolster together.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. 1
is a front elevational view of a mechanical press incorporating the shutheight adjustment mechanism of the present invention;
FIG. 2
is an enlarged sectional view of a single hydraulic tie rod assembly of the present invention;
FIG. 3
is a top plan view of the press of
FIG. 1
showing four hydraulic tie rod assemblies;
FIG. 4
is an fragmentary enlarged front elevational view of the bed of the mechanical press of
FIG. 1
;
FIG. 5
is a schematic of the feedback means of the present invention; and
FIG. 6
is a schematic, cross-sectional view of the bed and bolster combination of the present invention.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to
FIG. 1
, mechanical press
10
comprises a crown portion
12
, a bed portion
14
having a bolster assembly
16
connected thereto and uprights
18
connecting crown portion
12
with bed portion
14
. Bolster assembly comprises a bolster
17
having an attached lower die shoe
19
including a die
21
. An opposed die
25
is attached to an upper die shoe
27
connecting with slide
30
. A plurality of guide posts
29
are disposed between the upper and lower die shoes
25
, and
19
in a known fashion.
Uprights
18
are connected to or integral with the underside of crown
12
and the upper side of bed
14
. The slide
30
is attached to crown
12
for reciprocating movement in opposed relation to bed
14
.
Although press
10
is shown in a press down configuration, it could alternatively be constructed in a press up configuration by constructing the press upside down. In a press up configuration, slide
30
would be connected to the lower unit instead of the top unit, in this case, crown
12
. If slide
30
was connected to the lower unit, the lower unit could be referred to as the crown.
Leg members
24
are formed as an extension of bed
14
and are generally mounted on the shop floor
26
by means of shock absorbing pads
28
. Tie rods
20
a
extend through crown
12
, uprights
18
and bed portion
14
, and tie rods
20
b
extend through bed
14
and bolster
16
. Additionally, tie rods
20
a, b
are attached on one end with tie rod nut assemblies
22
of the present invention. On the other end of tie rods
20
a, b
are standard, non-expandable tie rod nuts
23
. Optionally, although not shown, both ends of tie rods
20
a, b
could each be provided with a tie rod nut assembly
22
to facilitate greater shutheight control.
Press shutheight is controlled by first measuring the shutheight between slide
30
and bolster
16
by a shutheight measuring means
32
such as a limit switch, an accelerometer or a non-contacting optical or electrical sensing means as is known in the art. A preferred non-connecting sensor is an eddy current transducer.
Measurement of shutheight may also be achieved by measuring the pressure loads or vibrations through the press. Alternate methods of measuring shutheight may include monitoring press speed or the quality of workpieces produced by the press. The present invention is directed to improve and supplement current shutheight adjustment mechanisms thereby permitting shutheight adjustment while press
10
is cycling (i.e., adjustment in motion).
In the present invention, each hydraulic tie rod nut assembly
22
is connected to a feedback system
34
which receives shutheight input from shutheight measuring means
32
(FIG.
5
). Each hydraulic tie rod nut assembly
22
includes an annular cylinder
36
mounted upon one of crown
12
, bolster
16
, and bed
14
, as appropriate, and about one of tie rods
20
a, b
(See FIG.
2
). Cylinder
36
includes an annular bore
38
about tie rod
20
a, b
into which an annular piston
40
is slidingly interfit. Piston
40
includes an annular threaded bore
42
which is threadably engaged on threads
44
of tie rod
20
a, b
. Piston
40
sealingly interfits within bore
38
by means of seals
46
. Seals
46
seal between piston
40
and cylinder
36
defining a chamber
48
. As shown in
FIG. 2
, chamber
48
is connected to an oil inlet
50
that is constructed through cylinder
36
. Oil inlet
50
is in communication with an oil line
60
in fluid communication with oil purged by a pump
64
(FIG.
5
). The present construction permits piston
40
to slide within cylinder
36
based on the pressure of oil injected through cylinder
50
.
On piston
40
and about tie rod
20
a, b
is threaded a tie rod nut
52
(as shown on tie rod
20
b
in FIG.
2
). Nut
52
includes an annular bore having threads
54
that engage threads
44
of tie rod
20
a, b
. The bottom surface
56
of tie rod nut
52
engages a top surface
41
of piston
40
. A metallic preload spacer element
58
is interfit between cylinder
36
and tie rod nut
52
to maintain a selected preload. Spacer
58
is ground or formed so as to be flat and interfit between cylinder
36
and nut
52
with barely any clearance. Spacer
58
will maintain the initial preload of the press in the event that oil pressure within chamber
48
is relieved. Spacer
58
thickness can be calculated on the basis of the theoretical or measured stretching of the tie rod, compression of the crown, uprights and bed of press
10
during operation.
The feedback means for automatically controlling the shutheight will be discussed in relation to FIG.
5
. However, it is understood and appreciated that alternative control arrangements may be utilized to control the shutheight and the required hydraulic pressure.
Automatic control of shutheight is maintained by a control feedback means
35
as shown in FIG.
5
. Prior to operation, the press operator inputs a preselected shutheight through line
71
into a comparator
72
. Feedback means
34
along with comparator
72
may comprise a microprocessor. Alternatively, comparator
72
may be constructed from a programmable logic controller as is known in the art. Comparator
72
receives input signals and provides output or control signals as a function of its inputs.
Shutheight measuring means
32
of
FIG. 1
transmits an actual shutheight measurement
74
through line
75
to comparator
72
during press operation. Comparator
72
compares the difference between the preselected shutheight
70
and the actual shutheight
74
and forms a control signal on line
76
to an oil pressurizing means such as oil pump
64
. Pump
64
may be a typical air-over-oil pump to variably control the oil pressure within tie rod nut assemblies
22
. Pump
64
connects to manifold
62
, thereby pumping oil into and controlling pressurized oil therein. Manifold
62
communicates the pressurized oil by oil lines
60
to various hydraulic tie rod nut assemblies
22
. The result of the comparison between the preselected shutheight
70
and the actual shutheight measurement
74
causes comparator
72
to vary the control signal on line
76
to pump
64
to vary oil pressure to the hydraulic tie rod nut assembly
22
, thereby changing the compression between press bed
14
and press crown
12
. Shutheight
25
is controlled by changing the oil pressure within chamber
48
.
Alternatively, comparator
72
, based on its inputs, may vary and send a control signal on a line
78
to manifold
62
to vary the applied pressure of oil to any particular tie rod nut assembly
22
. In this fashion, oil pressure within clearance space
48
may be controlled by a valve selectively opening and closing, such as an electric solenoid valve or throttle as is known in the art. The alternate valve may be integral to manifold
62
. If necessary, comparator
72
may control more than one pump
64
and manifold
62
.
If comparator
72
determines that the actual press shutheight
74
is too small, a control signal is sent through line
76
to cause pump
64
to increase pressure within chamber
48
, thereby increasing shutheight by compressing press bolster closer to press bed
14
. When the measured shutheight
74
is too large, comparator
72
will signal pump
64
to reduce pressure within chamber
48
.
At initial assembly, the press
10
will be preloaded at approximately full press tonnage. During this preload, oil is injected through oil inlet
50
into chamber
48
. This oil is then pressurized to approximately 1200 PSI for a typical 100 ton press to approximate the full press tonnage. During the preload process, the pressure within chamber
48
will cause piston
40
to slide within bore
38
away from crown
12
. As piston
40
slides away from crown
12
forcefully engaging and pressing into tie rod nut
52
, a larger space will develop between cylinder
36
and tie rod nut
52
. At the full preload pressure, the spacer element
58
of the preload separation between tie rod nut
52
and cylinder
36
is interfit therebetween. The insertion of spacers
58
are used to maintain the gap and preload stress between nut
52
and cylinder
36
.
The tie rod nut assembly
22
is preferably attached to each of the tie rods in press
10
. As shown in
FIG. 3
, four tie rod assemblies
22
are attached to the four tie rods
20
b
of press
10
.
FIG. 3
shows each tie rod nut assembly
22
connected by a high pressure oil hose
60
to a manifold
62
. However, it is envisaged that placing tie rod nut assemblies
22
on two or three of tie rods
20
b
may prove sufficient under certain circumstances.
The details of the combination of bed
14
and bolster
17
are best illustrated in FIG.
6
. In addition to bed
14
and bolster
17
(of bolster assembly
16
), the combination includes a plurality of tie rods
20
b
, a plurality of tie rod nut assemblies
22
, a quick access adjustment mechanism
80
, at least one limit stop
82
, and guide bushings
84
.
To reduce press shutheight, the operator would use the hydraulic system to increase pressure to adjustment mechanism
80
and decrease or eliminate pressure to the hydraulic tie rod nuts
22
. The comparator/monitoring system for automatic shutheight control could use a combination of inputs including pressure at adjustment mechanism
80
and chamber
48
.
Each bed
14
and bolster
17
is provided with a plurality of rod receiving channels
88
for receiving corresponding tie rods
20
b
. Additionally, bed
14
and bolster
17
further have a plurality of nut receiving cavities
90
formed therein, each receiving cavity
90
being associated with one of rod receiving channels
88
. Each nut receiving cavity
90
faces away from the area between bed
14
and bolster
17
.
Each tie rod
20
b
has an associated tie rod length
86
. Pressure-activated tie nut assemblies
22
permit fine tune adjustment of tie rod length
86
(to about 0.010 inches). This fine tune adjustment of the length involves corresponding adjustment of shutheight
74
(i.e., an increase in rod length/tension results in an increase in compression between the bed and bolster, thereby producing a shutheight decrease). In this environment, both the bed and the bolster end of each of tie rods
20
b
is provided with a tie rod nut assembly
22
, thereby facilitating a adjustment of the overall length of each tie rod
20
b
from either end thereof. However, it is also contemplated, although not shown that one of the bed set and bolster set of tie rod nut assemblies could be replaced with a set of standard nuts.
Quick access adjustment mechanism
80
is operatively positioned between bed
14
and bolster
17
. Quick access adjustment mechanism
80
is hydraulically controlled, being configured for receipt of an adjustable amount of a hydraulic fluid
92
and being supplied with a quick access piston
94
for acting upon hydraulic fluid
92
. The height adjustment achieved with quick access adjust mechanism
80
is referred to herein as quick access height adjustment amount
96
, as indicated in FIG.
6
. Quick access height adjustment amount
86
can be on the order of inches, thereby allowing relatively easy access to the area between bed
14
and bolster
17
. Conversely, quick access height adjustment amount
96
can be reduced to a new order of the required shutheight amount during press operations.
At least one limit stop
82
is provided to act as a limit for the degree of stretching possible within tie rods
20
b
and to act as a limit on the maximum quick access height adjustment amount
96
.
Guide bushings
84
are provided in each rod receiving channel
88
adjacent the interface region between bed
14
and bolster
17
. Guide bushings
84
help minimize the vibration of tie rods
20
b
.
The operation of tie rod nut assemblies
22
associated with the bed and bolster combination, in a manner similar to operation of tie rods
20
a
associated with crown
12
, uprights
18
, and bed portion
14
, is controlled via shutheight measuring means
32
in feedback system
34
. Further, each hydraulic tie rod nut assembly
22
associated with the bed and bolster combination is advantageously constructed and configured in a manner similar to those described for use with respect to crown
12
, upright
18
, and bed
14
.
In operation, press shutheight is controlled by first measuring the shutheight between slide
30
and bolster die
16
by a shutheight measuring means
32
such as a limit switch or a non-contacting sensing means such as an eddy current transducer or a laser/photo sensor. The use of multiple shutheight measuring means
32
permits detection of possible variances in shutheight across the press zone.
The present invention improves current shutheight adjustment mechanisms by permitting shutheight adjustment while press
10
is cycling (i.e., adjustment in motion). By comparing the measured shutheight value to a predetermined desired shutheight value, a decision is made whether to increase or decrease the shutheight of the press. Known means for creating this feedback system include programmable logic controllers and standard electronic computers that may be programmed to compare the two shutheight values and provide a signal to actuate a valve or pump (such as air over oil pump
64
).
Upon the condition sensed by feedback means
34
that shutheight should be increased, oil pressure within manifold
62
and therefore tie rod nut assemblies
22
is increased. From an approximate preload pressure of 1200 PSI for a typical 100 ton press, the feedback means
34
may vary the pressure from 1200 to 3500 PSI. This range of pressure changes should result in differences of approximately 0.010 inches in shutheight. Conversely, the shutheight can be decreased up to a maximum corresponding to the return of a tie rod to its original prestressed state, achieved by releasing the oil pressure within manifold
62
.
As shown in
FIG. 1
, a shutheight measuring means
32
is incorporated near slide
30
. A pressurizing means, such as a pump
64
for pumping pressurized oil, is connected by means of an oil line
61
to manifold
62
. Manifold
62
is connected by oil pressure lines
60
to the hydraulic tie rod nut assemblies
22
. The feedback means
34
may be directly incorporated on the motor controller
4
, motor
64
or on a separate unit.
The shutheight adjustment mechanism described may be installed easily to a press
10
without any changes in the press slide drive. Also, hydraulic tie rod nut assemblies
22
may be retrofitted to existing mechanical presses. By using a non-contacting shutheight measuring means, virtually no structural changes are needed to the press running gear. The feedback system described automatically changes the hydraulic pressure within hydraulic tie rod nuts
22
to vary the shutheight.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Claims
- 1. A press comprising:a crown and a bed attached together by a frame, said bed having a bolster attached thereto; a slide attached to said crown for reciprocating movement in opposed relation to said bed; a plurality of tie rods connecting between said bolster and said bed; a plurality of pressure-activated tie rod nut assemblies attached to at least two said tie rods adjacent one of said bolster and said bed so that when activated, said tie rod nut assemblies force said bolster toward said bed; a shutheight measuring means for measuring the shutheight of said press, said shutheight measuring means associated with said press; and feedback means connected to said shutheight measuring means and said tie rod nut assemblies for comparing a predetermined desired shutheight to the shutheight measured by said measuring means and pressure activating said tie rod nut assemblies when the measured shutheight deviates from the predetermined shutheight, whereby shutheight is controlled.
- 2. The press of claim 1 in which a tie rod nut assembly comprises:a cylinder block having a cylinder bore fit about said tie rod; a piston threadedly engaged about said tie rod and slidably disposed within said cylinder bore, thereby forming an inner chamber, said inner chamber pressurized with a liquid; and a tie rod nut threadably engaged about said tie rod and engaging said piston.
- 3. The press of claim 2 in which said inner chamber is further defined by seals between said piston and said cylinder block.
- 4. The press of claim 2 in which said liquid comprises oil.
- 5. The press of claim 2 in which said tie rod nut assembly includes a spacer interfit between said nut and said cylinder block to maintain a desired preload on said bolster without said tie rod nut assemblies being pressurized.
- 6. The press of claim 2 having at least two said tie rod nuts assemblies in which said inner chambers of said tie rod nut assemblies are connected together by a manifold.
- 7. The press of claim 2 in which said feedback means controls the shutheight of the press by altering the pressure within said inner chamber.
- 8. The press of claim 1 in which said feedback means comprises:a pump connected to said tie rod nut assemblies and activated by a control signal for changing the pressure of liquid communicated to said tie rod assemblies; and comparator means having input lines for a measured shutheight from said shutheight measuring means and a predetermined desired shutheight, said comparator means including a signal output line connected to said pump, said comparator means causing a control signal to be formed on said output line on the basis of a comparison between a measured shutheight and a predetermined desired shutheight.
- 9. A press comprising:a crown and a bed attached together by a frame, said bed having a bolster attached thereto; a slide attached to said crown for reciprocating movement in opposed relation to said bed; a plurality of tie rods connecting between said bolster and said bed; a plurality of pressure-activated tie rod nut assemblies, at least two said tie rods having at least one tie rod nut assembly mounted thereto adjacent one of said bolster and said bed, each said tie rod nut assembly including a cylinder block having a cylinder bore fit about said tie rod, a piston threadedly engaged about said tie rod and slidably disposed within said cylinder bore, thereby forming an inner chamber, said inner chamber pressurized with a liquid, and a tie rod nut threadably engaged about said tie rod and engaging said piston so that an increase in pressure within said inner chamber forces said tie rod nut away from said cylinder block; a shutheight measuring means for measuring the shutheight of said press, said measuring means operatively associated with said press; and feedback means connected to said shutheight measuring means and to said tie rod nut assemblies for comparing a predetermined desired shutheight to the shutheight measured by said measuring means and altering the pressure within each said inner chamber when the measured shutheight deviates from the predetermined shutheight, whereby shutheight is controlled.
- 10. The press of claim 9 in which said feedback means includes a pump to pressurize said liquid, said pump controlled by said feedback means.
- 11. The press of claim 9 in which said feedback means includes a manifold connected to said inner chambers of said tie rod nut assemblies.
- 12. The press of claim 9 in which said feedback means controls the pressure within each tie rod nut assembly individually.
- 13. The press of claim 9 in which said liquid is pressurized to between 1200 p.s.i. and 3500 p.s.i.
- 14. The press of claim 9 in which said tie rod nut assembly includes a spacer interfit between said tie rod nut and said cylinder block to maintain a desired preload on said bolster without said tie rod nut assemblies being pressurized.
- 15. The press of claim 9 in which said inner chambers of said plurality of said tie rod nut assemblies are connected together by a manifold.
- 16. The press of claim 9 in which said feedback means comprises:a pump connected to said inner chambers of said plurality of tie rod nut assemblies and activated by a control signal for changing the pressure of said liquid communicated to said inner chambers of said plurality of said tie rod assemblies; and comparator means having input lines for a measured shutheight from said shutheight measuring means and a predetermined desired shutheight, said comparator means including a signal output line connected to said pump, said comparator means causing a control signal to be formed on said output line on the basis of a comparison between a measured shutheight and a predetermined desired shutheight.
- 17. A press comprising:a crown and a bed attached together by a frame; a bolster attached to said bed at a position intermediate said bed and said crown; a slide attached to said crown for reciprocating movement in opposed relation to said bolster, said slide and said bolster having a shutheight associated therewith; a plurality of tie rods connecting said bolster to said bed; and a plurality of pressure-activated tie rod nut assemblies, at least two said tie rods having at least one tie rod assembly mounted thereto adjacent one of said bolster and said bed, each said tie rod nut assembly being configured for selectively adjusting at least one of tolerance and compression between said bed and said bolster to thereby effect a proportional change in the shutheight.
- 18. The press of claim 17, further comprising a quick access adjustment mechanism for adjusting a relative bolster height of said bolster, said quick access adjustment mechanism being operatively positioned between said bed and said bolster, said quick access adjustment mechanism being hydraulically activated.
- 19. The press of claim 18, further comprising at least one limit stop associated with one of said bed and said bolster, each said limit stop limiting a degree of relative bolster height adjustment that can be made using said quick access adjustment mechanism.
- 20. The press of claim 18, wherein said quick access adjustment mechanism and said plurality of tie rod nut assemblies are capable of being used conjunctively to effect the shutheight.
US Referenced Citations (11)