GB1566707A - Creation of Inventions and Patents with Artificial Intelligence

GB1566707A – Drawing presses
– Google Patents

GB1566707A – Drawing presses
– Google Patents
Drawing presses

Download PDF
Info

Publication number
GB1566707A

GB1566707A
GB4960975A
GB4960975A
GB1566707A
GB 1566707 A
GB1566707 A
GB 1566707A
GB 4960975 A
GB4960975 A
GB 4960975A
GB 4960975 A
GB4960975 A
GB 4960975A
GB 1566707 A
GB1566707 A
GB 1566707A
Authority
GB
United Kingdom
Prior art keywords
pressure
press
movable
tools
hydraulic
Prior art date
1975-12-03
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Expired

Application number
GB4960975A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

BRECKNELL HYDRAULICS Ltd HOLYO

HOLYOAK R

Original Assignee
BRECKNELL HYDRAULICS Ltd HOLYO
HOLYOAK R
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1975-12-03
Filing date
1975-12-03
Publication date
1980-05-08

1975-12-03
Application filed by BRECKNELL HYDRAULICS Ltd HOLYO, HOLYOAK R
filed
Critical
BRECKNELL HYDRAULICS Ltd HOLYO

1975-12-03
Priority to GB4960975A
priority
Critical
patent/GB1566707A/en

1980-05-08
Publication of GB1566707A
publication
Critical
patent/GB1566707A/en

Status
Expired
legal-status
Critical
Current

Links

Espacenet

Global Dossier

Discuss

Classifications

B—PERFORMING OPERATIONS; TRANSPORTING

B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL

B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL

B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing

B21D22/20—Deep-drawing

B21D22/28—Deep-drawing of cylindrical articles using consecutive dies

Description

(54) IMPROVEMENTS IN DRAWING PRESSES
(71) We, BRECENELL HYDRAULICS LIMITED, a British Company of 5 Lightning
Way, Northfield, Birmingham B31 3QJ,
West Midlands, and RONALD ARTHUR HOLY
OAK and ROBERT HOLYOAK both British subjects (trading as PENsNErT CONTROLS) of
Building No. 9, Pensnett Trading Estate,
Brierley Hill, West Midlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to deep drawing presses of the kind including relatively movable co-acting male and female dies which operate to effect an entire deep drawing process, the male die including a plurality of tools which are movable relative to each other in an operating cycle for forming a workpiece into a deep drawn article by successive automatic stages during a single stroke of the press (hereinafter referred to as “presses of the kind described”).
The object of the invention is to provide a hydraulic system for a deep drawing press which is adaptable and reliable in use, and efficient in operation.
According to the invention there is provided a hydraulic actuating system for a deep drawing press of the kind described, said system including back-up means for providing back-up pressure on movable tools of the male die comprising a plurality of independently operated pumps each supplying fluid pressure in use to respective cushion means acting on a respective one of said
movable tools which pressure is controlled
independently of the level of pressure applied by the other pump or pumps, the back-up
means being adapted to maintain back pres
sure on at least one of said tools at a pre
determined level during a respective part of
the operating stroke of the press and to automatically reduce said pressure on that tool to a predetermined lower level or to zero for a subsequent part of said stroke
A preferred embodiment of the invention, in the form of a three stage deep drawing
hydraulic press used for forming components such as filter bowls for motor vehicle from sheet metal in a single operating cycle, is now more particularly described with reference to the accompanying drawings, where in:- Figures 1-4 are diagrammatic vertical sectional views of the dies and associated structure of the press at respective successive stages of an operating stroke;
Figure 5 is a circuit diagram of hydraulic back-up means of the press; and
Figure 6 is a more detailed vertical section of said dies and associated structure.
Basically the press comprises an upper movable platen 10 which operatively carries a female die 11, the latter moving downward to engage a male die consisting of individual tools, in this case three in number, located in fixed bed structure 12 of the press.
Said tools comprise a first element in the form of an annular pressure pad 13 which is supported for limited vertical travel by a first set of three cushion hydraulic rams 14 (one only shown in Figures 1–4); a second element in the form of a sleeve 15 in sliding engagement with the central aperture of pressure pad 13 and supported for limited vertical movement by a second set of cushion hydraulic rams 16 (one only shown in Figures 1-4); and a third element in the form of a longer sleeve 17 in sliding engagement in sleeve 15 and supported for limited vertical movement on a third set of cushion hydraulic rams 18 (one only shown in Figures 1–4). Each set of rams 14, 16, 18 is mounted on a respective manifold 20, 21, 22 below structure 12 and is controlled from the hydraulic circuit shown in Figure 5.
Hydraulic liquid is fed to each set of rams l4, 16, 18 from respective independently driven pumps 23, 24, and 25 through check valves 26, 27 and 28, the pressure acting on the respective set of rams being predetermined by the setting of respective adjustable relief valves 29, 30 and 31. The pressure applied in each set of rams can be varied within the range 0-5000 psi and the provision of individual pumps and valves to each set ensure that adjustment in this range can be made to any individual set without affecting the pressure applied to- the oNer set or sets.
Associated with each set is a respective solenoid valve 32, 33 and 34 actuated automatically in succession by travel of the platen 10 to predetermined positions along its operating stroke.
Return flow from the sets of rams passes through respective relief valves 35, 36 and 37 and into a charging circuit 38 wherein the hydraulic fluid is passed to a pressure accumulator 39 to charge the latter with fluid. This accumulator is of the kind having a rigid container divided into two variable volume chambers by a flexible diaphragm (which may be formed as a bag) or movable piston, one chamber receiving the hydraulic fluid, aiid the other chamber containing a charge of nitrogen, thus contact between, and consequent mixing, of the hydraulic liquid under pressure with air or other gas is avoided. A make-up pump 40 circulates the liquid in circuit 38 through a heat exchanger 41 for cooling, and through a filter 42, and also makes up any losses in the hydraulic circuits due to leakage etc. All the pumps draw liquid from a common reservoir 43.
The sequence of operations during a stroke of the press is illustrated in Figures 1A.
At the start of the cycle (Figure 1) the press platen 10 is fully raised, and each set of cushion rams 14, 16, 18 is fully extended and maintained in the extended condition by their respective pumps 23, 24, 25 so that the male die tools 13, 15, 17 are arranged as shown in Figure 1 enabling a sheet metal workpiece 44 to be positioned in the open press.
The drawing operation is then commenced by lowering the press platen 10 to engage the respective dies. The lowest face of the female die 11 abuts the upper face of the annular pressure pad 13 and drives it downwards as shown in Figure 2 leaving the two sleeves 15, 17 protruding upwards to shape the workpiece by co-acting with the female die. The back pressure on. the first set of cushion ram 14 is determined by the setting of relief valve 29. At the end of a first part of the operating stroke solenoid valve 32 is energised to end all pumped back pressure on the first set of rams 14 leaving pad 13 free towtravel downwards in company with platen 10 while hydraulic fluid displaced from said rams is fed into accumulator 39.
The continued movement of platen 10 now. acts on the second set of rams 16 (Figure 3) driving the sleeve 15 of the male die downwards, its back pressure being determined by the setting of relief valve 30. Subsequently solenoid valve 33 is energised to reduce pumped back pressure on this set of rams to zero: or in some applications to tI4;wer level determined by the setting of
Zer relief valve 30o Continued movement now affects the third set of cushion rams 18 associated with the longer sleeve 17 which is now protruding through the sleeve 15 so as to continue the drawing operation on the workpiece, the back pressure in – these rams being determined by relief valve 31 and solenoid valve 34 is energised at a later stage to reduce such back pressure to zero; or to a level determined by another relief valve 31a. During the final part of the operating stroke (Figure 4) workpiece 44 is acted on by a fixed central punch 45 mounted on structure 12. At the conclusion of the stroke platen 10 travels upwards and the pressure in accumulator 39 returns the sets of rams 14, 16, 18 to the initial position of Figure 1 ready for the next cycle, at the same time ejecting workpiece 44, now formed as the deep drawn component for removal from the press.
While a three stage operation has been described it is to be understood that in some circumstances only two stages will be required in which case the second set of rams 16 may not carry a tool and may be kept inoperative. In other applications more than three tools may be required – and additional sets of cushion rams may be included for this purpose. The number of rams in each set may also be varied and the back pressure applied to any of the sets may be adjusted as required and may be zero or a lower level than the initial level during a later part of the operating stroke.
Referring to Figure 6 bed structure 12 consists of a cast steel die holder 50 bolted to the press bed, and having a steel shaft 51 running up through its centre carrying interchangable punch 45 on its upper end. The sets of cushion rams 14, 16, 18 (not shown in Figure 6) and the pressure pad 13 and sleeves 15 and 17, the latter mounted on respective holders 15a and 17a to make up the lower male die are assembled around said shaft. They locate within a guide structure 52 and the assembly may include one or more distance pieces 53 forming stops to positively limit relative displacement of the elements of the male die.
The upper or female die set 11 mounted on platen 10 includes a central ejector 54, and is built up as a stack of components shaped and assembled according to the drawing operation required and the shape of the finished component. The tools of the top of the top and bottom die sets are readily interchangeable for different types of work.
The particular press used in the above example is a forty ton press and deep drawn components having a diameter up to 100 mm and axial length of 180 mm can be formed from circular blanks up to 0.48 mm in thick ness. Trials have shown that a production rate of 800 finished components per hour can be readily achieved and the arrangement described is particularly reliable, requiring only routine maintenance during long production runs.
WHAT WE CLAIM IS:- 1. A hydraulic actuating system for a deep drawing press of the kind described, said system including back-up means for providing back-up pressure on movable tools of the male die comprising a plurality of independently operated pumps each supplying fluid pressure in use to respective cushion means acting on a respective one of said movable tools which pressure is controlled independently of the level of pressure applied by the other pump or pumps, the back-up means being adapted to maintain back pressure on at least one of said tools at a predetermined level during a respective part of the operating stroke of the press and to automatically reduce said pressure on that tool to a predetermined lower level or to zero for a subsequent part of said stroke.
2. A system according to Claim 1 including a respective pre-set adjustable pressure relief valve for determining the back pressure exerted by the cushion means associated with each said movable tool.
3. A system according to Claim 1 or 2 including a solenoid operated valve actuated by the dies reaching a predetermined relative position during the operating stroke to effect said automatic reduction in back pressure on said at least one tool.
4. A system according to any one of the preceding claims including a hydraulic accumulator to be charged with hydraulic fluid during the operating stroke and serving to return the movable tools to their initial position when the dies are moved apart.
5. A system according to claim 4 wherein said accumulator comprises a flexible diaphragm or movable piston within a rigid container and acted on by a charge of inert gas.
6. A system according to any one of the preceding claims including respective cushion means for acting independently on each of three movable tools of the male die.
7. A hydraulic actuating system for a press of the kind described substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
8. A deep drawing press of the kind described including an actuating system according to any one of the preceding claims.
9. A deep drawing press substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. described is particularly reliable, requiring only routine maintenance during long production runs. WHAT WE CLAIM IS:-

1. A hydraulic actuating system for a deep drawing press of the kind described, said system including back-up means for providing back-up pressure on movable tools of the male die comprising a plurality of independently operated pumps each supplying fluid pressure in use to respective cushion means acting on a respective one of said movable tools which pressure is controlled independently of the level of pressure applied by the other pump or pumps, the back-up means being adapted to maintain back pressure on at least one of said tools at a predetermined level during a respective part of the operating stroke of the press and to automatically reduce said pressure on that tool to a predetermined lower level or to zero for a subsequent part of said stroke.

2. A system according to Claim 1 including a respective pre-set adjustable pressure relief valve for determining the back pressure exerted by the cushion means associated with each said movable tool.

3. A system according to Claim 1 or 2 including a solenoid operated valve actuated by the dies reaching a predetermined relative position during the operating stroke to effect said automatic reduction in back pressure on said at least one tool.

4. A system according to any one of the preceding claims including a hydraulic accumulator to be charged with hydraulic fluid during the operating stroke and serving to return the movable tools to their initial position when the dies are moved apart.

5. A system according to claim 4 wherein said accumulator comprises a flexible diaphragm or movable piston within a rigid container and acted on by a charge of inert gas.

6. A system according to any one of the preceding claims including respective cushion means for acting independently on each of three movable tools of the male die.

7. A hydraulic actuating system for a press of the kind described substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

8. A deep drawing press of the kind described including an actuating system according to any one of the preceding claims.

9. A deep drawing press substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

GB4960975A
1975-12-03
1975-12-03
Drawing presses

Expired

GB1566707A
(en)

Priority Applications (1)

Application Number
Priority Date
Filing Date
Title

GB4960975A

GB1566707A
(en)

1975-12-03
1975-12-03
Drawing presses

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

GB4960975A

GB1566707A
(en)

1975-12-03
1975-12-03
Drawing presses

Publications (1)

Publication Number
Publication Date

GB1566707A
true

GB1566707A
(en)

1980-05-08

Family
ID=10452930
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB4960975A
Expired

GB1566707A
(en)

1975-12-03
1975-12-03
Drawing presses

Country Status (1)

Country
Link

GB
(1)

GB1566707A
(en)

Cited By (1)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

EP1387088A1
(en)

2002-08-02
2004-02-04
Special Springs S.r.l.
Device for delayed and/or slowed return of gas cylinders

1975

1975-12-03
GB
GB4960975A
patent/GB1566707A/en
not_active
Expired

Cited By (1)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

EP1387088A1
(en)

2002-08-02
2004-02-04
Special Springs S.r.l.
Device for delayed and/or slowed return of gas cylinders

Contact information