Olsson, Håkan (Skogsbärsvägen 4 KARLSKOGA, S-691 45, SE)
|1.||Impact machine comprising an impact unit (1), a machine stand and a tool unit (2) provided under the impact unit, characterised in that the impact unit is suspended via shock absorbers and that elevation members (Sa, 5b) are provided to raise and to lower the impact unit in a controlled way.|
|2.||Impact machine according to claim 1, characterised in that the machine stand comprises at least two vertical columns (4a, 4b), that the impact unit is suspended on said columns via said shock absorbers, that said elevator members are provided to raise and to lower the impact unit along said columns in a controlled way, and that the tool unit is provided between the vertical axes of at least two vertical columns.|
|3.||Impact machine according to claim 1 or 2, characterised in that said elevator members comprise hydraulic motion members (12,21), and that said shock absorbers consist of hydraulic fluid in said hydraulic motion members.|
|4.||Impact machine according to claim 3, characterised in that each of said at least two columns is provided with a hydraulic cylinder (12) and that respective column extends through the hydraulic cylinder, which is movable along a section of the column, which column section forms a stationary, through piston rod (21) and hydraulic piston (14) in the hydraulic cylinder.|
|5.||Impact machine according to claim 4, characterised in that said hydraulic cylinders are fixed connected mechanically to the impact unit.|
|6.||Impact machine according to any of claims 35, characterised in that said section of the column which forms a stationary piston rod (21) comprises a stationary piston ring (14), which forms a stationary hydraulic piston, that the inside of the hydraulic cylinder can slide on said piston ring, that the hydraulic cylinder comprises an upper end wall (17) with a leadthrough (18) for a section (4a") of the stationary hydraulic rod (21) above the piston ring, and a lower end wall (19) with a leadthrough (20) for the section (4a") of the stationary hydraulic rod (21) below the piston ring, an upper hydraulic chamber (15) between the piston ring and the upper end wall, and a lower hydraulic chamber (16) between the piston ring and the lower end wall.|
|7.||Impact machine according to claim 6, characterised in that a first conduit (24) for supply and leading away of hydraulic fluid is connected to the upper hydraulic chamber in each of said hydraulic cylinders (12), that a second conduit (25) for supply and leading away of hydraulic fluid is connected to the lower hydraulic chamber (16) in each of said hydraulic cylinders, and that a valve (26) which is common for all the hydraulic cylinders (12) is provided to control the flow of hydraulic medium in said first and second conduits in said hydraulic cylinders.|
|8.||Impact machine according to any of claims 47, characterised that said shock absorber at least partly or substantially consists of the hydraulic fluid in said hydraulic chambers.|
|9.||Impact machine according to claim 8, characterised in that at least any expansion/compression chamber (62,63) is provided, which expansion/compression chambers contain/s hydraulic fluid and communicate/s with said upper or lower hydraulic chamber, respectively.|
BACKGROUND ART Impact machines for working by the employment of a high kinetic energy are machines for metal working, such as cutting and punching, forming metal components, powder compaction and similar operations, in which the velocity of a ram, which may consist of a press piston may be essentially higher than in conventional presses. The working principle is based on the development of a very high kinetic energy of short duration instead of a high static press force of long duration. The dynamic forces of short duration which are generated at the ram impact and which in impact machines of prior art are conveyed around in the system via stand and foundation may be several thousands times larger. In order to be able to absorb such large forces, impact machines of prior art are equipped with very strong and heavy stands and foundations according to principles which are common in connection with conventional presses. Nevertheless the dynamic, shock type force pulses that are developed in impact machines are not damped in such heavy, conventional systems. The stress on all joints therefore become very large, as well as on sensitive components, e. g. electronic components for controlling those hydraulic valves which usually form parts of impact machines, which may cause a great risk of failures. Large, unwieldy stands also give rise to problems in connection with service, change of tool unit or of tool insets in the tool unit, changing the height of the impact unit above the tool unit, etc.
BRIEF DISCLOSURE OF THE INVENTION It is the purpose of the invention to address the above complex of problems. More particularly, the invention aims at achieving in the first placethe following advantages: -to essentially isolate the impact unit from shock waves from the impact via the machine stand, particularly to isolate the impact unit from the very high shock waves which may arise when the working of the working material is performed through a single, very powerful impact, -to make a very simple and quick change of the height of the impact unit above the machine unit possible, and
-to reduce the total mass of the machine as compared with impact machines of prior art.
Through the isolation of the impact unit from shock waves from the impact via the stand, an increased working life of the whole machine can also be achieved.
According to a development of the invention, the impact unit can also be turned aside, which further simplifies maintenance and changing of tool unit or of tool inserts, which in turn makes set up time still shorter.
According to the invention, the impact unit is suspended via dampers, and motion means are provided to raise and to lower the impact unit in a controlled manner.
Preferably said motion means comprise hydraulic motion members, wherein said dampers consist of hydraulic fluid in said hydraulic motion members.
According to an aspect of the invention, the impact machine comprises at least two fixed (stationary) vertical columns, on which the impact unit is suspended via said dampers, wherein said motion means, which preferably are hydraulic, are provided to be able to raise and to lower the impact unit in a controlled manner along said columns.
According to another aspect of the invention, the invention is characterised in that each of said at least two stationary columns are provided with a hydraulic cylinder, and that the respective column extends through the hydraulic cylinder, which is movable along a section of the column. The column section forms a through, stationary hydraulic piston in the hydraulic cylinder.
Further characteristic features and aspects of the invention will be apparent from the patent claims and from the following description of a preferred embodiment.
BRIEF DESCRIPTION OF DRAWINGS In the following description of a preferred embodiment, reference will be made to the accompanying drawings, in which Fig. 1 is a perspective view of the impact machine according to the preferred embodiment of the invention, and Fig. 2 at a larger scale and partly schematically in a section shows a hydraulic cylinder and its control unit, which is common for all hydraulic cylinders in the system of the invention.
DESCRIPTION OF PREFERRED EMBODIMENT The impact machine according to the embodiment shown in Fig. 1 consists of the following main components; an impact unit 1, a tool unit 2 under the impact unit 1, resting on a base or foundation 3, a stand consisting of four vertical columns 4a, 4b one in each of the corners of the base 3, and on each such column an elevator-and damping unit 5a, 5b slideably mounted on each such column.
The central part 7 of the impact unit 1 contains components which hydraulically or in any other way can accelerate a ram, e. g. a striking piston, to a very high velocity according to principles which are known per se. The interior design of the impact unit and its mode of operation do not form part of the present invention and will therefore not be disclosed here in detail.
The tool unit 2 is placed symmetrically on the base 3 between the four columns 4a, 4b with an impact body 8 centred under the not shown ram of the impact unit 7. Nor does the design of the tool unit 2 form any part of the invention, wherefore it is shown only schematically. It should, however, be mentioned that the tool unit 2 contains tools, which normally consist of a plurality of components for working with the use of a high kinetic energy, such as cutting, stamping, forming, punching, etc., of metallic products.
The impact body abuts an upper of these tools and transmits the kinetic energy of the ram to said tool and hence to the working material. There is a need to be able to change tool unit, tools or tool inserts, perform maintenance work, etc., wherefore it is desirable that the tool unit 2 and its various parts are easy to access.
According to the embodiment of the invention the tool unit 2 is connected to four elevator and damping units Sa, 5b via four arms 1 Oa, 1 Ob. How the elevator and damping unit 5 a, which is united with the impact unit via the rigid arm lOa, is designed, now shall be described with reference to Fig. 2.
In Fig. 2 a hydraulic unit is designated 12 and a control unitfor controlling the flow of hydraulic fluid from the hydraulic chamber to the hydraulic cylinder is designated 13.
These main components are also shown in Fig. 1 in connection with the elevator and damping unit 5a. That drawing shows that the control unit 13 is arranged against one side of the hydraulic cylinder 12. In order to show the design more clearly, the control unit is in Fig. 2 shown extending out from the hydraulic cylinder 12.
On column 4a, as well as on the three other columns 4b, there is an annular, cylindrical section with an outer diameter which corresponds to the inner diameter of the hydraulic cylinder 12. Said section forms a stationary piston ring 14, against which the hydraulic cylinder 12 can slide. Above the piston ring 14, the annular gap between the inside of the hydraulic cylinder 12 and the column 4a, forms an upper hydraulic chambers 15 and below the piston ring 14 the annular gap between the inside of the hydraulic cylinder 12 and the column 4a forms a lower hydraulic chamber 16. The lower hydraulic chamber 16 has a larger cross section area than the upper hydraulic chamber 15, i. e. the lower part 4a'of column 4a below the piston ring 14 is more slender than the upper part 4a" of column 4a above the piston ring 14. In its upper end, the hydraulic cylinder has an upper end wall 17 with a sealed lead-through 18 for said upper column part 4a"and in the lower end there is in a corresponding way a lower end wall 19 with a sealed lead- through 20 for the lower part 4a"of the column. Together those parts of column 4a which include the piston ring 14 and sections of said lower and upper column parts 4a' and 4a"through piston rod are generally designated 21. w A first hydraulic conduit 24 is connected to the upper hydraulic chamber 15, and a second hydraulic conduit 25 is connected to the lower hydraulic chamber 16 for supply and drainage of hydraulic fluid. The flow of hydraulic fluid to and from the hydraulic chambers, and hence also the pressure in the chambers, can be controlled by means of a slide valve, which is generally designated 26. The slide valve is of a type which has been known in the art for very long and is more specifically of the type which conven- tionally is used in hydraulically operated copying lathes and which therefore is often called copying valves. In a through, cylindrical boring 27 there is a fixed insert body 28 having cylindrical sections which sealingly contact the wall of the boring 27. In the insert body 28 there is a through, central, cylindrical valve chamber 29, in which a slide 30 can be moved between different positions. The slide 30 has along its length a number of annular recesses, which form a corresponding number of annular spaces, which are movable together with the slide 30, said annular spaces being denominated first gap 31, second gap 32, upper gap 33, and lower gap 40. The upper end of slide 30 is designed as a pin, which slideably and sealed extends through an upper end wall 34 of the boring 27.
The insert body 28 in a similar way as the slide 30 has a number of peripheral recesses, which form a number of annular spaces, which are denominated first space 34, second space 35, third space 36, upper space 37, and lower space 38.
To the first space 34 there is connected a pressure conduit, here denominated first channel 42, to the second space 35 there is connected a +/-conduit, here denominated second channel 43, and to the third space 36 there is connected a drainage conduit, here denominated third channel 44. To the upper space 37 there is further connected an upper channel 45 and to the lower space 38 there is connected a lower channel 46. Said first channel 42 is via a hydraulic hose connected to a hydraulic pump or other pressure source for the supply of hydraulic fluid to the first space 34. The second channel 43 is a plus/minus channel, which automatically obtains the set pressure which provides an equilibrium for the whole impact unit 1. This hydraulic pressure is lower than the pressure in the pressure source, which is connected to the first channel 42. The third channel is a drainage-or return conduit for leading away hydraulic fluid to a hydraulic tank.
The upper channel 45 is via en upper branch conduit 47 connected to the first channel 42 and in a corresponding way the lower channel 46 is connected to the third channel 44 via a lower branch conduit 48. The flows in said upper and lower channels 45,46 can be controlled by means of the constriction valve 49 and 50, respectively.
Besides the above mentioned conduits, there is a first connection conduit 24'which via a system of hydraulic hoses, such as the hose 53 which is denominated first hydraulic hose, or via channels in the impact unit, connect the first hydraulic conduit 24 and hence the upper hydraulic chamber 15 in the hydraulic cylinder 12 in the elevator-and damping unit 5a to the upper hydraulic chamber of all the other hydraulic cylinders in the elevator and damping units 5b. In a corresponding way there is a second connection conduit 25'which connects the second hydraulic conduit 25 and hence the lower hydraulic chamber 16 with the other lower hydraulic chambers of the hydraulic cylinders in the elevator and damping units 5b via hydraulic hoses or via channels in the impact unit 1. These hydraulic hoses are represented by the section of a hydraulic hose that is designated 54 and denominated second hydraulic hose. In other words, the first hydraulic chambers in all the four hydraulic cylinders 12 in me elevator and damping units 5a and 5b communicate with one another via said first hydraulic conduits 24, first connection conduits 24', and said first hydraulic hoses 53, and in a corresponding way the lower hydraulic chambers 16 communicate with one another via said second hydraulic conduit 25, second connection conduit 25'and second hydraulic hose 54. This also means that the slide valve 26 serves all the four hydraulic cylinders in the system.
Under the insert body 28 there is a lower, tubular insert body 56, which is pressed snug into the boring 27. A vertical, cylindrical channel 57 extends through the insert body 56.
The channel 57 has the same diameter as a cylindrical, downwards projecting projection 58 of the slide 30. The slide 30 with its projection 58 rests via a spring cushion 59 on a control pin 60, which is slideably movable in the channel 57. A helic spring 61 is provided in the hydraulic medium in the lower gap 40.
The operating pin 60 can be operated manually for setting the slide 30 in different positions or can be operated automatically by means of a not shown, remote controlled actuator.
When the impact unit 1 is in operation, the to some degree compressible hydraulic fluid in the hydraulic chambers 15,16 and in the conduits connected to the hydraulic chambers function as shock absorbers. In this connection there is an optimum with reference to the flexibility/dampening/capacity of the system, since it is also desirable that the impact unit 1 is maintained basically in place, i. e. is stationary, as the impact piston is accelerated. Depending on the degree of desired dampening capacity one or more hydraulic fluid filled expansion/compression chambers can be provided, which communicate with one of or with both the hydraulic chambers in the different hydraulic cylinders. However, these expansion/compression chambers do not communicate with one another. Thus e. g. an upper expansion/compression chamber 62 can be provided in the form of a boring in the upper column part 4a"and in corresponding column parts in the other columns 4b, and a lower expansion/compression chamber 63 can be provided in the form of a boring in the lower column part 4a'and in corresponding parts of the other columns 4b. These upper and lower expansion/compression chambers 62,63 communicate with the upper hydraulic chamber 15 and with the lower hydraulic chamber 16, respectively, via connection conduits 64,65 provided in the region of the piston ring 14.
In order to further increase the accessibility of the tool unit the entire impact unit 1 can be turnable, preferably so that it can be turned aside about the column 4a. The other columns 4b are dividable just below the lowest conceivable position of the elevator and dampening units Sb, where quick-couplings are provided. The couplings are schemati- cally shown in Fig. 1 and are designated 9.
The described assembly for shock dampening and for height regulation functions in the following way. It is supposed that the impact unit 1 is in a certain work position,
represented by the position of the hydraulic cylinder 12 relative to the stationary hydraulic piston 21, Fig. 2. The slide 30 is in the position shown in Fig. 2, which means that the upper hydraulic chamber 15 is connected to the hydraulic pump or to corres- ponding pressure source via said first channel 42, said first space 34, and said first hydraulic conduit 24, which in turn communicates with the upper hydraulic chambers 15 in the other hydraulic cylinders via the first connection conduit 24'and said first hydraulic hose 53 or corresponding. The lower hydraulic chambers 16 are filled with hydraulic fluid and communicate with one another, but the slide 30 has closed the communication of the lower hydraulic chambers 16 with any of said channels 42-44.
When the impact unit 1 performs a working operation, the not shown ram/impact piston is accelerated very quickly to a very high velocity and strikes the impact body 8 on top of the tool unit in order to work the working object in a desired way, e. g. to perform a punching operation, compacting a powder body, or the like. This unavoidably causes a reaction movement, which gives rise to very powerful shock waves, which are trans- mitted via the tool unit 2, and the base 3 to the four columns 4a, 4b. Before the shock waves proceed via the arms lOa, lOb back to the impact unit 1, they are, however, damped to a harmless level in the hydraulic medium in the elevator-and damping units Sa, 5b. More specifically, the hydraulic medium in the hydraulic chambers 15,16 and in the volumes which communicate with the hydraulic chambers 15,16 and in the preferably provided expansion/compression chambers 62,63 works as a dampening medium. The damping degree can be modified through a suitable dimensioning of the volume of hydraulic medium in the said spaces. It is also conceivable to provide devices for adjusting said volume, preferably to provide such devices in the expansion/ compression chambers 62,63.
When the impact unit 1 shall be raised, e. g. for change of tools in the tool unit 2 or for replacement of the entire tool unit, for performance of maintenance work, or for any other reason, the following procedure applies. The manoeuvre pin 50 is slowly moved upwards until the lower hydraulic chambers 16 in all hydraulic cylinders 12 in the assembly will communicate with the drainage channel, i. e. said third channel 44 via said second gap 32 which is moved to a lower position, said gap also connecting the plus/ minus channel, i. e. said second channel 43 with the drainage channel 44. At the same time the upper hydraulic chambers 15 are connected with the pressure channel, i. e. with said first channel 42, via the first gap 31 in the slide valve 26. Since the upper hydraulic chambers 15 are pressurised, at the same time as the lower hydraulic chambers 16 are released from pressure and can be drained, the hydraulic cylinder will be displaced
upwards because of the pressure which acts on the upper end wall 17. All the cylinders 12 in the elevator and damping units 5a, 5b thus are moved upwards and lift the entire impact unit 1 upwards via the arms lOa, lOb until the slide 30 is returned to its normal position shown in Fig. 2.
The velocity of movement of the slide 30 upwards in the slide valve 26 is suppressed and can be controlled by adjustment of the pressure in said upper and lower gaps 33 and 40, respectively by means of the constriction valves 49 and 50, respectively. The movement is also damped by the spring cushion 59.
When the impact unit I thus has been elevated, the tool unit 2 is easy to access. The accessibility can be further increased by turning the entire impact unit 1 aside by turning about the column 4a, after the coupling devices 9 on columns 4b have been released.
When the impact unit 1 shall be lowered, the slide 30 instead is brought downwards to its bottom position in which the upper and lower hydraulic chambers 15 and 16 in all the four hydraulic cylinders 12 communicate with one another and with the pressure channel and with the plus/minus channel, i. e. with said first and second channels 42 and 43 via the first gap 31 of the slide valve 26, at the same time as said third channel 44, the drainage channel, is closed by the slide 30. The two hydraulic chambers 15 and 16 thus become pressurised with the same hydraulic pressure, but because the cross section area of the lower hydraulic chamber 16 is larger then the cross section area of the upper hydraulic chamber 15, the hydraulic cylinders 12 are driven downwards under the influence of the pressure which acts on the lower end wall 19, until the slide 30 has been returned to its normal position. By means of the constriction valves 49 and 50 the movement of the slide 30 can be controlled very accurately and hence also the positioning of the impact unit 1 relative to the tool unit 2.
The purpose of the spring 61 is to move the slide 30 to its upper position if the hydraulic pump or a corresponding pressure source which pressurises said first channel 42 is switched off. Therein the impact unit 1 is moved to an upper position to be positioned there.
It shall be understood that the invention can be modified within the frame of the appending patent claims and that the disclosed embodiment is not limiting, as far as the scope of the patent is concerned. For example, the number of columns co-operating with the elevator and dampening devices need not be four. Two columns may suffice,
particularly in case of smaller impact units. The two columns in that case may be located in two corners of the base 3, oriented diagonally relative to one another. In order to stabilise the assembly, guiding columns or other guides may be provided in the other two corners. Also three columns provided with elevator and dampening devices are conceivable. However, the number of columns should not exceed four. It is true that more columns can further improve the damping capacity as well as the lifting ability in the system, but at the same time, the machinery will be more complicated and more expensive and the accessibility of the tool unit 2 would be impaired.
Further it is possible to complete the hydraulic dampening means according to the invention with further hydraulic and/or mechanical damping means. It should also be understood that the elevation function of the elevator and damping units 5a, 5b can be controlled in other ways than by means of the described slide valve.
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