GB2133741A - Hydraulic vulcanizing press - Google Patents
Hydraulic vulcanizing press Download PDFInfo
- Publication number
- GB2133741A GB2133741A GB08320469A GB8320469A GB2133741A GB 2133741 A GB2133741 A GB 2133741A GB 08320469 A GB08320469 A GB 08320469A GB 8320469 A GB8320469 A GB 8320469A GB 2133741 A GB2133741 A GB 2133741A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pressure
- hydraulic
- cylinder
- hydraulic pressure
- pneumatic
- Prior art date
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/26—Programme control arrangements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/16—Control arrangements for fluid-driven presses
- B30B15/165—Control arrangements for fluid-driven presses for pneumatically-hydraulically driven presses
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
For pressurizing and holding the pressure in a hydraulic pressure cylinder 1 of the press, a pneumatically operated hydraulic pressure booster 10, is provided for supplying a desired hydraulic pressure to the cylinder 1 in a hydraulic circuit (c) on the pressure actuation side A of said cylinder. In the pneumatic input circuit for the pneumatic booster 10, there are provided switching devices 22, 24 for switching pressurized air fed to the pneumatic booster between high pressure air for boosting the hydraulic pressure to a desired hydraulic pressure, and low pressure air for holding the desired hydraulic pressure after the desired hydraulic pressure has been attained. Warning means may be provided comprising a measurement instrument, for measuring the flow rate of hydraulic fluid generated by the booster 10 and issuing a signal to a setter (a pressure rising setter, or pressure holding setter). If the actual measurement signal exceeds the set signal an alarm is actuated. <IMAGE>
Description
SPECIFICATION Hydraulicvulcanizing press
The present invention relates to a hydraulic vulcanizing press in which pressurisation of a hydraulic pressure cylinder in the press is carried out and the pressurizing force is held by making use of a pneumatic booster which coverts a pneumatic pressure to a hydraulic pressure according to an area ratio of a piston and which continuously feeds the hydraulic pressure until the hydraulic pressure in the hydraulic cylinder balances with a load.
A pneumatic boosterthat is available in the afore-mentionedtype of hydraulic vulcanizing press has a characteristic as illustrated in Figure, 1, where it will be noted that, in the case of setting a pressing force forthe hydraulic cylinder by the intermediary of the fed pneumatic pressu re, the delivered hydraulic pressure is proportional to the fed pneumatic pressure;;
(1 ) if the fed pneumatic pressure is set at a pressure corresponding to a desired hydraulic pressure for pressing, ittakes time until the hydraulic cylinder is pressurized up to the desired hydraulic pressure becausethe delivery rate of pressurized oil is reduced as the hydraulic pressure rises, and
(2) if there pneumatic pressure is set higherthan the pressure corresponding to the desired hydraulic pressure for pressing, the hydraulic pressure would eventually rise higher than the desired hydraulic pressure and hence a product or a machine would be adversely affected, although the time necessitated before attaining the desired hydraulic pressure is shortened.
Onthe other hand, ifthefed pneumatic pressure is set higherthan the pressure corresponding to the desired hydraulic pressure for pressing and the hydraulic pressure of a delivered pressurized oil is controlled by means of a pressure reducing valve, then the aforementioned shortcoming can be elimiated. However, the pressure reducing valve must always discharge drain oil for controlling the hydraulic pressure. Also, during the pressure holding period, even ifthere is no leakage from the pressure cylinder and/or other pipings, it is necessaryto continue to supply pressurized oil. Hence, a correspondingly large capacity of pneumatic booster is necessitated.
Moreover, a waste of energy results.
An object of the present invention is to provide a hydraulic vulcanizing press in which the hydraulic cylinder can be pressurized upto a desired hydraulic pressure within a short period oftime and can hold the desired hydraulic pressure exactly, and in which there is no waste of energy.
According to one aspect ofthe present invention, there is provided a hydraulic vulcanizing press comprising a pneumatic boosterfor supplying hydraulic pressure to a hydraulic circuit on the pressure actuation side of a hydraulic pressure cylinder in said hydraulicvulcanizing press in order to pressurize and hold the pressure in the cylinder, and a switching deviceforswitching pressurized airfed to the pneumatic booster between high pressure airfor boosting the hydraulic pressure to a desired pressure level and low pressure air for holding said desired hydraulic pressure after said desired level has been attained.
Another object of the present invention isto provide a hydraulic vulcanizing press in which a pressing force ofthe hydraulic pressure cylinder can be maintained art a predetermined pressure by supplying hydraulic pressure from a hydraulic pressure generator device, and abnormal lowering of the pressing force of the pressure hydraulic cylinder can be detected at an early time to generate an alarm so that the possibility of an accident can be preliminarily prevented.
According to another aspect of the present inven tion,there is provided a hydraulicvulcanizing press comprising a hydraulic pressure generator device for supplying hydraulic pressure to a hydraulic circuit on the pressure actuation side of a hydraulic pressure cylinder in the hydraulic vulcanizing press in order to pressurize and hold the pressure in the cylinder, and warning means consisting of a measurement instru mentfor measuring the flow rate offluid having said hydraulic pressure and for issuing a measurement signal, a setterfor issuing a set signal for said flow rate, a comparatorfor generating an alarm signal when the measurementsignal exceeds the set signal, and an alarm acuated by said alarm signal.
The above-mentioned and other features and objects of the present invention will become more apparent by reference to the following description of one preferred embodimentofthe invention, taken in conjunction with the accompanying drawings, and modifications thereof, wherein:
Figure lisa diagram showing characteristics of a pneumatic booster,
Figure 2 is a general system diagram showing said preferred embodiment ofthe present invention,
Figure 3 is a longitudinal cross-section view of a hydraulic pressure generator device (a booster) shown in Figure 2,
Figure 4 is a system diagram of warning means provided in Figure 2 and
Figure 5 is a timing chart showing an operation sequence in the system shown in Figure 2.
Referring to Figure 2, a hydraulic pressure cylinder 1,forexample, in a hydraulic press type tyre vulcanizing press (not shown), is adapted to clamp metallic moulds forvulcanizing a tyre, i.e. to apply a pressing force to said moulds. Forth is, the hydraulic chamber A on the pressure actuating side of the piston 1 a ofthe cylinder 1 is coupled to a hydraulic circuit (a), while the hydraulic chamber B on the other, piston rod side 1 b of the cylinder (the cylinder return side), is coupled to a hydraulic circuit (b). Both hydraulic circuits (a) and (b) are coupled through a directional switching valve 2 to a low-pressure source 3 and a return tank4. In addition, a pilot check valve 5 and a pressure switch 6 are provided.The aforementioned hydraulic circuit operates in such a mannerthat, if the directional switching valve 2 is shifted to a position 2a, then hydraulic pressure supplied from the lowpressure hydraulic pressure source 3 is introduced :ntothehydraulicchamberAviathecircuit(a),and at the same time liquid within the hydraulic chamberBis discharged to the return tank 4via the circuit b. Hence, due to hydraulic pressure within the hydraulic cham
ber A, the rod 1 b is projected by the intermediary of the piston la, resulting in a pressing operation ofthe tyre vulcanizing press (not shown). Thereafter, ifthe directional switching valve 2 is shifted to position 2b, hydraulic pressure is introduced into the hydraulic chamber B, and at the same time the actuated liquid within the hydraulic chamber A is discharged.Hence, the rod lband the piston la are retracted to restorethe hydraulic cylinder 1, and hence release pressure.
In addition, a hydraulic pressuresupplycircuit (c) having a check valve 6 is coupled to the abovementioned hydraulic circuit (a) on the pressure actuation side of the hydraulic cylinder. In this circuit (c), between a hydraulic pressure tank 8 and a check valve 7 is disposed a hydraulic pressure generator device 10 for boosting hydraulic pressure P1 on the side of the hydraulic pressure tank 8 up to a higher hydraulic pressure of P2 or P3 to supply such higher hydraulic pressure to the hydraulic cylinder 1. More particularly, a pneumatic booster 10 is provided which is pneumatically actuated to boostthe original hydraulic pressure P1 to the higher hydraulic pressure P2 or P3to be supplied to the hydraulic cylinder.
Referring to Figure 3, the pneumatically actuated booster 10 consists of a pneumatic cylinder 11 formed in a broad, transverse cross-section shape containing a piston 1 Oa therein and having inlet/outlet ports 11 a and 11 b for pneumatic pressure, and a hydraulic cylinder 12formed in a narrowtransversecross- section shape having a plunger 1 0b advanced and retracted therethrough, which communicates with the cylinder 11 and is delimited by a pair of checkvalves 13 and 14, provided in the hydraulic pressure supply circuit (c).When the plunger 1 Ob is projected into the cylinder 12 (downwardly as viewed in Figure 3) via the piston 1 Oa by pressurized air flowing into the cylinder 11 through the inlet/outlet port 11 a (and flowing out of said cylinder th rough the inlet/outlet port 11 b), the hydraulic pressure P1 within the cylinder 12 is raised up to a higher pressure of P2 or P3, and then flows into the circuit (c) via the check valve 14 as shown by the arrow. On the other hand, when pressurized air is discharged through the inlet/outlet port 11 a and enters the cylinder 11 through the inlet/outlet port 11 b, the plunger 1 Ob is retracted (raised) via the piston 1 0a.
Hence the volume within the cylinder 12 is increased, resulting in a negative pressure therein; thereby, liquid at pressure P1 on the side of the hydraulic pressure tank 8 flows into the cylinder 1 2through the checkvalve 13. Therefore, by repeating the aforementioned operations, liquid flow at a higher hydraulic pressure, P2 or P3 is generated in the circuit (c), and this hydraulic pressureflow is supplied to the hydraulicchamberAofthe hydraulic cylinder 1 through the aforementioned hydraulic circuit (a).It is to be noted here that, since the transverse crosssection of the pneumatic cylinder 11 has a very large area ratio with respect to the transverse cross-section ofthe hydraulic cylinder, the higher hydraulic pressure P2 or P3 can be obtained with a relatively low pneumatic pressure.
The pneuma, ic circuitforthe aforementioned boos ter10consistsoffeed line (d) at a pressureA2 connected between a pneumatctic pressure feed source 20 and the inlet/outlet port 11 a of the booster
11, and includes a pressure reducing valve 21, a directional switching valve 22 and a check valve 23. A feed line (e) at pressure A3 is connected between the feed source 20 and the aforementioned inlet/outlet port 11 a, and includes a pressure reducing valve 25 and a directional switching valve 24, as shown in
Figure 2. Thus by manipulating the respective directional switching valves 22 and 24, a pneumatic pressure can be fed eitherfrom the pressure source 20 to the booster 11 through the inlet/outlet port 1 la, or discharged from said boosterthrough said inlet/outlet port.
The pressure reducing valves 21 and 25 are pro videdforthe purpose of reducing the feed from the source 20 which is at a pressure A1, the pneumatic pressure fed to the booster 10 being set at the pressure
A2 by the reducing valve 25, and at the pressure A3 by the reducing valve 21. Here, it is assumed that > A2 is fulfilled and, in the circuit ofthe illustrated embodiment, the set pressure in the reducing valve 25 is chosen atthe higher pressure ofthe two set pressures.
The directional switching valves 22 and 24 serve to feed pressure at A2 and A3 respectively, fed through the pressure reducing valves 21 and 25 to the booster 10 or shut out pressure from the booster 10, and the check valve 23 serves as an inhibit valve for preventing the air at pressure A2 fed through the switching valve 24 from returning to the pneumatic pressure feed source 20 th rough the directional switching valve 22.
Furthermore, as shown in Figure 3, a rod 30 projecting from the pneumatic cylinder 11 ofthe booster 10is provided on the uppersurface ofthe piston 1 0a so that a cam 31 mounted at the tip end portion of the rod may actuate a limit switch 32; also a counter 33 is provided for counting the number of actuations ofthe limit switch 32, as shown in Figure 4, toform ameasurementinstrumentformeasuringthe flow rate of hydraulic fluid generated by the booster 10 (the flow rate through the hydraulic pressure supply circuit (c)) on the basis of the count of the counter 33 and issuing a measurement signal 33a.In addition, there is provided a pressure rising period setter 34for issuing a pressure rising period set signal 34a corresponding to the aforementioned measurementsignal 33a, and a similarpressure holding period setter 35 for issuing a pressure holding period set signal 35a; thereby a pressure rising period set signal 34a corresponding to a number of necessary cycles of booster actuation,that is, corresponding to the aforementioned measurement signal 33a, under a normal condition during the period when the hyd raulicpressureinthehydraulicchamberAofthe hydraulic cylinder 1 rises from a no load condition up to a predetermined pressing force, and a pressure holding period set signal 35a corresponding to a numberof necessary cycles per unit time of booster actuation, i.e. corresponding to the aforementioned measurement signal 33a, for supplementing a normal leakage rateofthe hydraulicfluidto hold a predetermined pressing force during the period when the pressing force is held, can be preset. In the aforementioned respective processes, that is, in the pressure rising process and in the pressure holding process, the aforementioned measurement signal 33a is compared with the pressure rising period set signal 34a and the pressure holding period set signal 35a respectively, by means of a comparator 36, and there is provided warning means in which, when the above-mentioned measurement signal 33a has exceeded the corresponding set signals 34a and 35a, an alarm signal 36a is generated.In response to the alarm signal 36a issued from the comparator 36, an alarm 37 such as a buzzer or the like may be automatically actuated. Furthermore, there is provided operation interruption means responsive to the above-mentioned alarm signal 36a forstopping an automatic operation ofthe hydrauliovulcanizing press, orfor controlling the hydraulic vulcanizing press, in the case of the pressing force is being held, not to enter the next cycle when the present cycle has been completed. This operation interruption means itself may possibly take many differentforms of known control means depending upon the structure ofthe hydraulic vulcanizing press, and therefore, description of a more detailed structure oftheoperation interruption meanswill be omitted here.
Morover, modification can be made such that the pressure rising period setter 34 and the pressure holding period setter 35 respectively can issue two steps of set signals 34a and 35a. Then control can be made such that, if the measurement signal 33a has exceeded the first step set signal, then only the alarm 37 is actuated, and if it has exceeded the second step set signal, then not only the alarm 37 is actuated, but also the hydraulic vulcanizing press is subjected to emergency interruption and the operation cycle is stopped.
It is to be noted that, while a booster having the structure shown in Figure 2 has been described as one example of the hydraulic pressure generator device in the above-described preferred embodiment, the hydraulic pressure generator device should not be limited to such a booster. Thus, the present invention is also applicable to the case of pressurizing by means of a pump. In addition, while description has been made of a measurement instrument which measures the flow rate of hydraulic liquid flow indirectly by measuring booster cycles with the aid of means mounted on a piston ofthe booster, the present invention should not be limited to this particular example. Thus, it is also possible to detect, for example, the inner pressure of the pneumatic circuit for actuating the booster or of the hydraulic cylinder ofthe booster by means of a pressure switch.Moreover, it is also possible to employ means for directly detecting the flow rate itself ofthe hydraulicfluid flow in the hydraulic pressure supply circuit.
In the following, in connection to a series of operations consisting of clamp, pressure-rise, pressure-hold and unclamp, the operation ofthe respective component parts will be explained.
Figure5 shows variations in time of the operations ofthe respective switching valves and the inner pressure within the hydraulic chamberA. The levels 2a, neutral and 2b, the levels 24a and 24b and the levels 22a and 22b represent the respective positions ofthe directional switching valves 2,24 and 22 respectively, and the modes of change ofthe positions ofthe respective switching valves are indicated by thick solid lines. An inner pressure P1 within the hydraulic chamber A is a pressure that is necessaryfor driving the pressing cylinder 1, and this pressure is equal to the pressure ofthe low-pressure hydraulic pressure source 3.A pressure P2 isthe pressure necessary for pressing, and this pressure is equal to the pressure obtained with the aid of the booster 1D by the pneumatic pressure A2 controlled through the pressure reducing valve 21. A pressure P3 is a pressure obtained with the aid ofthe booster 10 by the pneumaticpressureA3controlledthroughthe pressure reducing valve 25.
Upon pressing with the hydraulic vulcanizing press, at a momentt1, the directional switching valves 2,24 and 22 are respectively switched to the positions 2a, 24a and 22a. Owing to the position 2a ofthe directional switching valve 2, the hydraulic pressure P1 is supplied to the cylinder 1 to drive said cylinder, and at a moment t2 the inner pressure within the hydraulic chamber A attains the pressure P1. Underthis condition, the hydraulic cylinder clamps the metallic moulds.Afterthe moulds have been clamped, at the moment t3, pressurized air at pressure A3 is fed to the pneumatic booster through the directional switching valve 24 and takes the position 24a.As a result, hydraulic fluid at pressure P3 is delivered from the pneumatic booster 10, and hence the inner pressure within the hydraulic chamberAwould rise along the curve 16 shown in Figure 5. When the inner pressure within the hydraulic chamberA has reached the desired pressure P2, that is, at a moment t4, the directional switching valve 24 is switched from position 24a to a position 24b and the directional switching valve 2 is switched from position 2a to the "neutral" position, so that feed of the air at pressure A3 to the pneumatic booster 10its stopped, while the directional switching valve 22 retains its position 22a to feed the air at pressure A2 corresponding to the desired hydraulic pressure P2.Therefore, the hyd raulic chamber A is held at the hydraulic pressure P2, and thus the operation enters the pressure holding step.
During the pressure holding period, that is, during the period oft4 t5, if the pressurized liquid within the hydraulic circuit leaks out and the pressure within the hydraulic chamberA is lowered, the pneumatic booster 10 would be automatically driven by the pneumatic pressure A2 fed through the directional switching valves 22 and the booster 10 supplies the pressurized liquid until the pressure within the hydraulic chamber A reaches the desired pressure P2.
During the pressure hold period, the directional switching valve 2 is kept at the "neutral" position and the directional switching valve 24 is kept at position 24b, but when the pressure hold period has elapsed, that is, when it has become a time t5, the directional switching valve 2 and 22 are switched to the positions 2b and 22b, respectively, to releasethe clamp. When the clamp is released, the inhibit of inverse flow through the check valve 5 is also released. Hence, the pressurized liquid within the hydraulic chamberA is discharged through the check valve 5 inversely.
It is to be noted that switching ofthe pneumatic circuit from the directional switching valve 24to the directional switching valve 22 in the above description i.e. switching ofthe directional switching valve 24 from position 24a to position 24b at the momentt4, is carried out afterthe pressure switch 6 has been set at the pressure P2.
In connection to the above description, the curve 17 in Figure 5 representsthe mode of increase of the hydraulic pressure in the hydraulicchamberA in the eventthatthe pneumatic booster 10 is driven only by the pneumatic pressure A2 corresponding to the desired hydraulic pressure P2. By comparing curves 16 and 17, it will be readily seen that the pressure rise time can be greatly shortened according to the present invention.
In addition, with regardto the directional switching valve 2, modification could be made such that the neutral position ofthe valve 2 is omitted to make only two step switching between the positions 2a and 2b; at the momentt5 it is switched from position 2a to position 2b and the state of position 2b is maintained from the momentt5 to the moment t7. Alternatively, the directional switching valve 2 may be maintained at position 2a during the period to t3, it may be switched to the "neutral" position atthe momentt3, and it may be maintained at "neutral" during the period t3 -- 5 Fu t5.Furthermore, the directional switching valve 24 could be switched to the position 24a at the moment t3, then it could be maintained at the state of position 24a during the period t3 t4, and switched to position 24b atthe momentt4, and it could be maintained at the state of position 24b during the period4~ t8 (corresponding tOt3) Still further, the directional switching valve 22 could be switched to
position 22a at the moment4, maintained atthe state
of position 22a, then switched to position 22b atthe moments5 and maintained at the state of position 22b
during the period t5 -- t9 (corresponding tot4).
In addition, it is to be noted that lowering of the pressing force ofthe hydraulic cylinder 1 caused by the conventional leakage ofthe hydraulic liquid can be prevented by supplying hydraulic liquid held at the higher pressure P2 with the aid ofthe hydraulic pressure generator device, that is the booster 10 to the hydraulic chamberA of the cylinder 1, and thereby the pressing force produced by the cylinder 1 can be maintained at a predetermined value.Furthermore, lowering ofthe pressing force produced by the cylinder 1 would result in increase of the flow rate of the hydraulic fluid (at the hydraulic pressure P2) on the side ofthe hydraulic pressure supply circuit (c) with respecttothehydraulicchamberAofthecylinder1, and also it is sensitively reflected as an increase of cycles ofthe booster 10.Moreover, since the increase is virtually not influenced from the side ofthe hydraulic vulcanizing press, by comparing theflow rate detected signal of the aforementioned hydraulic fluid flow detected either indirectly, or directly, with the corresponding set signal, abnormal lowering, i.e., lowering exceeding a predetermined value ofthe pressing force produced by the pressing hydraulic cylinder, can be detected appropriately at an ea4y timeto generate an alarm. If necessary, it is also possible to automatically stop the hydraulic vulcaniz- ing press in such an abnormal case; hence, the present invention can greatly contribute to prevention of unacceptable products, prevention of dangers, etc., and it can remarkable enhance the working efficiency of a hydraulic vulcanizing press. Especially, upon holding a pressing force in the case of requiring a long vulcanizing period extending over several minutes two several hours, as is the case with a tyre vulcanizing press, the above-mentioned effects ofthe present invention are quite remarkable.
Claims (5)
1. A hydraulic vulcanizing press, characterised in thatthere is provided a pneumatic booster for supplying hydraulic pressure to a hydraulic circuit on the pressure actuation side of a hydraulic pressure cylinder in said hydraulic vulcanizing press in order to pressurize and hold the pressure in the cylinder, and a switching device for switching pressurizedairfedto said pneumatic booster between high pressureairfor boosting the hydrualic pressure to a desired pressure level and low pressure air for holding said desired hydraulic pressure after said desired level has been attained.
2. A hydraulic vulcanizing press as claimed in
Claim 1, characterised in that said switching device is composed of a parallel pneumatic pressure feed circuit including series connections, each consisting of a pressure reducing valve and a directional switching valve, which are connected in parallel to each other between a pneumatic pressure source and said pneumatic booster.
3. A hydraulic vulcanizing press as claimed in
Claim 2, characterised in that one ofthe pressure reducing valves in said parallel pneumatic pressure feed circuit is preset so as to feed high pressure air or boosting the hydraulic pressure to said desired level, and the other pressure reducing valve is preset so as to feed low pressure air having a lower pressure than said high pressure air for holding said desired level.
4. A hydraulic vulcanizing press, characterised in that there is provided a hydraulic pressure generator device for supplying hydraulic pressure to a hydraulic circuit on the pressure actuation side of a hydraulic pressure cylinder in said hydraulic vulcanizing press in orderto pressurize and hold the pressure in the cylinder, and warning means consisting of a measurement instrumentfor measuring the flow rate offluid having said hydraulicpressure and for issuing a measurement signal, a setterfor issuing a set signal for said flow rate, a comparatorforgenerating an alarm signal when said measurement signal exceeds said set signal, and an alarm actuated by said alarm signal.
5. A hydraulic vulcanizing press constructed, arranged and adapted for use substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP76283U JPS59107226U (en) | 1983-01-10 | 1983-01-10 | Pressure pressure monitoring device for hydraulic vulcanization press |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8320469D0 GB8320469D0 (en) | 1983-09-01 |
| GB2133741A true GB2133741A (en) | 1984-08-01 |
| GB2133741B GB2133741B (en) | 1987-02-18 |
Family
ID=11482702
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08320469A Expired GB2133741B (en) | 1983-01-10 | 1983-07-29 | Hydraulic valcanizing press |
| GB08524656A Expired GB2167706B (en) | 1983-01-10 | 1985-10-07 | Hydraulic vulcanizing press |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08524656A Expired GB2167706B (en) | 1983-01-10 | 1985-10-07 | Hydraulic vulcanizing press |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS59107226U (en) |
| DE (1) | DE3325301C2 (en) |
| GB (2) | GB2133741B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2178450A (en) * | 1985-07-26 | 1987-02-11 | Mitsubishi Heavy Ind Ltd | Drying laundry by squeezing |
| CN101961881A (en) * | 2010-07-28 | 2011-02-02 | 支洋波 | Preparation method of compressing inorganic adhesive fiberboard at normal temperature and preparation equipment |
| CN103029320A (en) * | 2012-11-29 | 2013-04-10 | 一重集团大连设计研究院有限公司 | Hydraulic overload protective system capable of setting tonnages and working method thereof |
| CN103362895A (en) * | 2013-07-31 | 2013-10-23 | 常州神力电机股份有限公司 | Oil inlet system of 160T punch press overload protection hydraulic oil cylinder |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2731811A1 (en) * | 1995-03-17 | 1996-09-20 | Gec Alsthom Acb | System for controlling hydraulic pressure in closed space, e.g. for hydraulic press cylinder |
| EP2327884B1 (en) * | 2009-11-30 | 2013-04-17 | Caterpillar Work Tools B. V. | Hydraulic device for hydraulic cylinders |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2907800A1 (en) * | 1979-02-28 | 1980-09-11 | Erich Kalt | Hydraulic position monitoring system for valve - has holes around valve seat leading to pressure-operated switch indicating when valve is closed |
-
1983
- 1983-01-10 JP JP76283U patent/JPS59107226U/en active Granted
- 1983-07-13 DE DE19833325301 patent/DE3325301C2/en not_active Expired
- 1983-07-29 GB GB08320469A patent/GB2133741B/en not_active Expired
-
1985
- 1985-10-07 GB GB08524656A patent/GB2167706B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2178450A (en) * | 1985-07-26 | 1987-02-11 | Mitsubishi Heavy Ind Ltd | Drying laundry by squeezing |
| CN101961881A (en) * | 2010-07-28 | 2011-02-02 | 支洋波 | Preparation method of compressing inorganic adhesive fiberboard at normal temperature and preparation equipment |
| CN103029320A (en) * | 2012-11-29 | 2013-04-10 | 一重集团大连设计研究院有限公司 | Hydraulic overload protective system capable of setting tonnages and working method thereof |
| CN103029320B (en) * | 2012-11-29 | 2015-03-11 | 一重集团大连设计研究院有限公司 | Hydraulic overload protective system capable of setting tonnages and working method thereof |
| CN103362895A (en) * | 2013-07-31 | 2013-10-23 | 常州神力电机股份有限公司 | Oil inlet system of 160T punch press overload protection hydraulic oil cylinder |
| CN103362895B (en) * | 2013-07-31 | 2016-05-18 | 常州神力电机股份有限公司 | A kind of 160 tons of punch press overload protection hydraulic jack oil feeding systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6343046Y2 (en) | 1988-11-10 |
| GB8320469D0 (en) | 1983-09-01 |
| DE3325301C2 (en) | 1985-10-03 |
| DE3325301A1 (en) | 1984-08-09 |
| GB2167706A (en) | 1986-06-04 |
| GB2167706B (en) | 1987-02-18 |
| GB8524656D0 (en) | 1985-11-13 |
| GB2133741B (en) | 1987-02-18 |
| JPS59107226U (en) | 1984-07-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930729 |