GB2310472A

GB2310472A - Hydraulic coupling

Info

Publication number: GB2310472A
Application number: GB9702891A
Authority: GB
Inventors: Thure Ekman
Original assignee: Dart Engineering AG
Current assignee: Dart Engineering AG
Priority date: 1996-02-23
Filing date: 1997-02-12
Publication date: 1997-08-27
Anticipated expiration: 2017-02-12
Also published as: GB9702891D0; DE19706998A1; SE510139C3; JPH108488A; SE9600690D0; SE9600690L; FR2745358A1; SE510139C2; GB2310472B

Description

2310472 TITLE Coupling arrangement on a first mobile unit, and a second

unit which can be coupled to the latter.

TECHNICAL FIELD

The present invention relates to an arrangement for ensuring the possibility of coupling a first mobile unit to a second unit which is used by the first unit. As first unit, mention may be made here of trucks, loaders, lorries, etc. Examples of the second unit that may be mentioned are equipment of various types, for example sweeping or cutting units, snowplows, lifting apparatus, etc. The possibility of coupling includes, in addition to mechanical coupling of the first and second units, also automatic and/or mechanical hydraulic coupling via a is quick- coupling function in the said first and second units, which are provided respectively with male and female coupling part(s) included in the quickcoupling function.

PRIOR ART

It is already known to be able to connect equipment of the type mentioned to first mobile units of the type mentioned. Particularly in the case of large plant machinery, it is known to be able to use vehicles which are temporarily provided with different types of equipment in order to satisfy requirements arising at different times of the year.

It is also already known to be able to supply the equipment or equivalent with energy from the first mobile unit in question, which is therefore provided with one or more power sources which are used in order to drive the function(s) included on or in the equipment. The power sources can be hydraulic and if appropriate also electrical. When connecting the equipment to the vehicle or equivalent, hydraulic and if appropriate also electrical connection(s) can be established in the known case. The connection(s) of the power sources can thus take place in conjunction with the mechanical coupling of the equipment to the vehicle.

it is also known per se, in this context, to use quick-coupling functions for coupling and uncoupling the different hydraulic circuits or systems or the electrical circuits.

It is also already known to be able to effect the coupling function from the driver's cab or equivalent so that the driver does not need to leave the vehicle in conjunction with coupling or uncoupling the units and the hydraulic and electrical circuits or systems.

DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM

Coupling of equipment or equivalent to loaders, vehicles, trucks, timbercutting machines, etc., is often is done outdoors under various temperature conditions. The equipment generally includes one or more hydraulic circuits or one or more hydraulic systems which are to be supplied with power from the hydraulic power source(s) of the loader or equivalent. When the equipment is decoupled, its hydraulic circuit(s) and/or hydraulic systems are also decoupled. Since there should be a high degree of freedom from spillage from the hydraulic system, the hydraulic circuit or equivalent of the equipment is closed off during the decoupling with the aid of one or more valves or closing members which ensure that no leakage (or only a very small leakage) of the working medium in the hydraulic system takes place. This means that the pressure in the working medium can increase considerably from the time of decoupling of the equipment to the time when the equipment is to be coupled up once again. in order to effect coupling of the hydraulic source(s) of the mobile unit to the hydraulic circuit(s) or hydraulic system of the equipment when high pressures (for example 500 bar or more) prevail in the last-mentioned circuit/circuits/syotems, an efficient coupling arrangement is required. The invention aims to solve this problem, among others.

The invention proposes the use of a pressure- eliminating arrangement. in addition, there is generally a distinct requirement for the coupling of the equipment or equivalent to the first mobile unit to be able to be performed solely by the driver of the first mobile unit, without he or she leaving the driver's position. This places special demands on the pressure-eliminating arrangement being able to function in this case too. The invention can also solve this problem.

There is also a distinct requirement that the hydraulic coupling and hydraulic uncoupling should be able to take place with a high degree of freedom from spillage despite the pressure- eliminating function. This problem too is solved by the invention.

In accordance with the invention, the hydraulic is coupling arrangement is able to be arranged such that undue wear and tear of the quick-coupling functions or of the parts which perform these functions does not occur. The coupling of the quick-coupling parts will also be able to be carried out using self-locking and self- holding arrangements which take up separating forces in the coupling on account of pressure increases in the hydraulic system or equivalent. The invention solves this problem too.

There is also a need to be able to produce a coupling arrangement which precludes any possible mix up, i.e. the coupling should not lead to different hydraulic lines/hydraulic circuits being coupled together incorrectly (mixed up). In addition, it must be possible for play in the suspension or locking arrangement for the quick-coupling functions or the quick-coupling parts relative to the f irst unit and the second unit to be compensated so that effective coupling can take place despite said play. In addition, two or more hydraulic quick-coupling functions will be able to be connected upon connection of the equipment to the mobile unit together with a quick- coupling function for electricity, through which electrical components in the equipment or equivalent will be supplied with power with one or more electric power sources in the first mobile unit. it is 4 also important that the coupling arrangement for the hydraulics and if appropriate the electrics system can be executed and arranged so that the view from the driver's cab is not affected. Likewise, it must be possible for the hydraulic circuits or equivalent to be closed off in an essentially spillage-free manner at the coupling site of the hydraulics in the event of unintentional uncoupling of the equipment or equivalent from the first mobile unit. In certain cases the arrangement must also be such that manual coupling of one or more quick- couplings can be carried out in conjunction with the desired automatic coupling of the hydraulics and if appropriate the electricity. The invention also solves this set of problems..

There is a requirement that the eliminator func- tion should be able to be applied in one or more quickcouplings, which places special demands on the latter. The invention solves this problem too and gives particulars concerning a coupling which is free from spillage to a high degree and which is intended to be used in the context specified.

SOLUTION That which can principally be regarded as characterizing an arrangement in accordance with the above is that one or both of the f irst and second units is/are arranged with pressure - eliminating members which come into operation upon said automatic and/or mechanical coupling for the quick-coupling function. When there is an overpressure prevailing in the hydraulic system or hydraulic circuit/hydraulic circuits of the second unit, the pressure-eliminating members eliminate this overpressure when said function comes into play. The coupling can therefore be carried out counter to overpressure in the hydraulic system or the hydraulic circuit or circuits.

In one embodiment, one part in each pair of male and female parts in the quick-couplings to each unit is provided with a pressure eliminator which can be activated by the second part in said respective pair of male - 5 and female coupling parts. The pressure eliminator eliminates an overpressure prevailing in said one part and/or in the hydraulic system or hydraulic circuit which is/are connected to the one part. In an alternative embodiment, both parts in the respective pair of male and female parts can be provided with a pressure-eliminating function.

The quick couplings which are used here for coupling of the respective hydraulic circuit or hydraulic system are in this case arranged so that the couplings and uncouplings can take place essentially free from spillage via said quick-coupling parts. In a further embodiment, the quick-coupling parts are arranged with a mutual self-holding function which is activated upon is coupling of the first and second units and thus brings about mutual mechanical locking. In a preferred embodiment, the male or f emale parts in one or more pairs of quick couplings are furthermore arranged in an attachment in the first unit. The corresponding female and male coupling parts in said pair of quick-coupling parts are arranged in a second attachment in the second unit. The mechanical locking of the quick- coupling parts to one another prevents separating forces occurring on the attachments in the event of variable pressure prevailing in the lines to the quick-coupling parts. The arrangement can also include one or more quick-couplings for elec tricity, and in one embodiment each attachment arrangement includes two double-acting hydraulic functions and a number of electrical functions, for example one to six, together with a return line (positive) for the electricity. In the coupling arrangement, use can also be made of one or more conical control plugs which ensure a control function between the quick-coupling parts which reduces the wear due to coupling. The attachments and the quick-coupling parts can also be arranged so that the risk of mix-up is avoided upon coupling of two or more pairs of quick-coupling parts. In a preferred embodiment, the attachments are mounted in a resilient manner in the first and second units so that any play between the attachments and the units can be compensated by the spring function. The attachments with associated hydraulic and electrical quick couplings are preferably arranged in such a way on the first and second units that the view from the driver's cab of the first mobile unit is not obstructed. Thus, the second attachment can be arranged between outer, upper and lower frame beams or bar elements present on the second unit. The first attachment on the first mobile unit can be disposed in a corresponding manner.

In a preferred embodiment, pressure- eliminating members are used both in the male part and female part in each pair of quick couplings for the hydraulics. one coupling part in each pair has moreover a longitudinally is displaceable inner sleeve which has at its outer end a projecting part which extends essentially parallel to an activation section in the second coupling part of the pair. Between the projecting part and the activation section it is possible to arrange a sealing arrangement with sealing elements which are acted on by a specific configuration on the activation section and thereby ensure a highly reliable initial activation function which prevents said leakage or ensures a high degree of freedom from spillage. At its part allowing working medium through, said inner sleeve is furthermore arranged to bear a longitudinally displaceable valve body in said one part. The working medium can be conveyed through said projecting and activation parts, and the part supporting the pressure eliminator in the inner sleeve is arranged behind said inner sleeve. The second part is preferably arranged with volume- swallowing function and the pressure eliminator of the second part is. arranged behind this volume-swallowing function.

ADVANTAGES By means of what has been proposed above,an effectively operating coupling function is obtained for hydraulics even under outdoor conditions involving large temperature variations due to sun, cold, etc. If so desired, the automatic coupling can be combined with or replaced by a manual coupling function for the hydraulics and if appropriate electricity. A long useful life can be guaranteed for the coupling arrangement, and by means of the arrangement having first and second attachments for the hydraulic couplings, if appropriate together with electric couplings, a high degree of interchangeability is possible for the units in relatively large plant machinery. Previous arrangements with a fixed arrange- ment in the first and second units can be dispensed with, and great flexibility of use of the components involved can be utilized, which considerably reduces the cost of the coupling functions as such. A high degree of freedom from spillage can be guaranteed by virtue of the fact is that the new generation of quick-coupling functions can be used. The coupling procedure itself can be carried out from the driver's cab by one and the same person, without he or she leaving the driver's position.

DESCRIPTION OF THE FIGURES

A presently proposed embodiment of an arrangement which has the characteristic features of the invention will be described hereinbelow with reference to the attached drawings in which:

Figure 1 shows the front parts of a first unit (truck) and parts of a second unit (equipment) from the side, Figure 2 shows, in partial longitudinal section, the male and female couplings included in a quick coupling function with hydraulic systems in the first and second units, Figure 3 shows, in longitudinal section, the quick coupling parts according to Figure 2 in the coupled position, principally shows, in longitudinal section, an alternative embodiment of the quick-coupling parts, Figure 4 shows, from the side, quick-coupling parts arranged In the attachments in the f irst and Figure 3a second units, Figure 5 shows an end view of the fastening arrangement for the attachments in the unit concerned, e.g. the second unit, shows, from the side, a control function between the first and second units, Figure 7 shows, from the side, alternative pressureeliminating functions in the first and second units, principally show in cross-section, and from below and from above, respectively, alternative fastening arrangements for attachments in the first or second unit, Figure 9 shows, from the side, the coupling of the first and second units via an intermediate coupling part which has quick-coupling parts which can cooperate in the coupling with corresponding quick-coupling parts In the first and second units, and shows, from the side, quick-coupling parts in the second unit which can be coupled manually to corresponding quick-coupling parts in the first unit.

Figure 6 Figs 8-8b is Figure 10 DETAILED EMBODIMENT In Figure 1, reference number 1 designates a first mobile unit in the form of a loader, and reference number 2 designates a second unit which can be coupled to the first unit and is in the form of a lifting device, e.g. with forks 2a for pallets or equivalent. The second unit in securely coupled by a mechanical arrangement 3 which can be of a type known per se.

Figures 2 and 3 show a quick-coupling function for hydraulics included in the coupling arrangement between the first and second units. Said function comprises one or more pairs of quick couplings, of which one is shown in Figure 2, where the female part is designated by 4 and the male part by 5. The quick couplings will couple and uncouple hydraulic lines, 9 - circuits or systems which are a ymb olically designated by 6, 6a and 7, 7a. In an alternative embodiment, the placings can be reversed or mixed, i.e. one and the same attachment can have both f emale and male couplings and another attachment can correspondingly have male and female couplings. The lines 6, 7 can be fastened in the couplings in a known manner using nut connections.

The hydraulics here comprise, in a manner known per se, one or more hydraulic power sources which are placed in the first unit and which will operate hydraulic functions and components in the second unit (e.g. snowplow guidance, sweeping and cutting functions, lifting function, etc.). In the present example, the male part is placed in the first unit and the female part in the is second unit. In the case shown, a work f low 8 will be conveyed, in the coupled position of the quick coupling, from the circuit/system 6a via the female coupling and male coupling to the circuit/system 7a. An interactive work flow exchange can be effected per se between the Circuits/systems 6 and 7, respectively, so that the hydraulic flow also travels in the opposite direction 81. It will be possible for the coupling of the parts 4, 5 to be carried out counter to pressure P1 at least in the one part 5. If so desired, the arrangement can be set up so that coupling can also take place counter to pressure P, P1 in both parts 4, 5. It will also be possible for the coupling to be carried out with considerable freedom from spillage, e.g. at most 1.0 zal per coupling. In order to manage the abovementioned functions, both the female and male couplings are provided with pressure-eliminator functions 9, 10 and with inner sleeve 11 and volumeswallowing arrangement 12, in the parts 4 and 5, respectively. An regards the pressure-eliminating and volume- swallowing arrangements in the female part, these are shown only symbolically. in the present case, the female part works without such functions, since the overpressure is in the first instance assumed to exist in the equipment, i. e. in the male part. In the case of reversed placing of the male and f emale parts in the first and second units, it in by contrast only the female part which is provided with pressure -eliminating and volume- swallowing arrangements. In order to reduce the number of different variants of the coupling parts, it may be advantageous in one embodiment to have both said functions in both the male and female couplings. In addition, the couplings include an initial sealing arrangement which ensures that the initial sealing function necessary for the freedom from spillage is obtained between the coupling parts before the puncturing or puncturings of the respective possible overpressure P, P1 is/are effected. The initial sealing function is divided across the parts 4, 5 and is symbolically indicated by 13 and 14, respectively. Said inner sleeve and is volume-swallowing arrangements guarantee initially comparatively small coupling forces, which is of great importance in the case of possible manual couplings of the female and male parts. The female part is additionally provided with an inner sleeve 15 which serves, inter alia, as protection against dirt and prevents dirt from penetrating into a space 16 between the sleeves 11 and 15 where a spring 17 works, and into which space 16 a nipple end 18 on the male part 5 can be pushed in conjunction with the coupling of the parts 4, 5. Locking balls 19 for mutual locking of the parts 4, 5 in the pushed-together state also operate in the space 16 by means of the locking balls assuming, in accordance with Figure 3, a position of interaction with the nipple end 18, via one or more recesses 20 thereon. The balls are arranged in a ball race 21 which is longitudinally displaceable relative to the outside 4a of the female part 4. Reciprocal longitudinal displacement movements 22 between the parts 4, 5 can be effected by means of parts 23, 24 which can be acted on by an external guidance function and which in this case are represented by the first unit (e.g. a loader) and the second unit (e.g. the equipment). The activation parts 23, 24 thus consist of fastening beams on the first and second units.

In Figure 2 the first and second units are uncoupled and separated, while in Figure 3 they are mechanically coupled in accordance with Figure 1. The sleeve 15 holds the balls 19 raised in inner recess(es) in the ball race. The nipple end drives the sleeve 15 downwards (inwards) upon coupling, and, at a position where the recess(es) 20 islare opposite the balls, the latter can be pressed down and retained in the recess(es) 20 by a lower surface or inner surface in the ball race. When the ball race is in the pressed-down position for the balls, the ball race can execute a certain slight longitudinal displacement movement which is smaller than 1, but still significant since a certain mutual mobility can be regarded as existing for the activation members 231, 241 on account of the mobility between the first and is second units. Thus, in accordance with the invention, the parts 4, 5 can be pushed together and locked securely, i.e. automatic self-locking is obtained, with the balls 19 after puncturing has taken place by means of the pressure eliminator/pressure eliminators 9 and 10, respectively. The end position of longitudinal displacement of the ball race in determined by an outwardly projecting front flange 21a on the sleeve body part 4.

Figure 3a shows a modified design of the female and male couplings 41 and 51. In this case the inner sleeve 151 has a different design, with, among other things, a bearing part 1Sal which centers a valve body 4c in the part 4. The bearing part has a number of throughholes 15all for working media. The design of the outer part 15b of the sleeve permits a considerable initial sealing capacity with the specific stepped design of the nipple end on the male part 51, the valve body of which has been designated by Sal. The initial sealing can then be accompanied by a pressure-eliminating function in one or both of the coupling parts. The coupling is made easier by the volume-swallowing function in one or both of the couplings. Upon coupling in the case where both parts have pressure eliminators, the puncturing takes place in succession, starting with the lowest pressure being punctured first.

In Figure 4, reference number 25 designates a bar member arranged edgeways on the first unit (e.g. the loader). A number of such bar members are held together by transverse beams 26, 27 in the width direction of the unit. Arranged between two such bar members there is an attachment 28 for a number of quick couplings, e.g. two quick couplings 29, 30 for hydraulics, and one quick coupling 31 f or electricity. in a manner corresponding to that in the case of hydraulics, the last- mentioned quick coupling conveys electricity from one or more power sources 32 on the first unit to one or more components 33 (lamps, lights, etc.) on the second unit. In the present case. the male parts of the quick coupling are applied in the attachment 28. This comprises a front and a rear bar plate 35, 36 arranged in frame-closing parts 37 on the first unit. The second unit (the equipment) is provided with an attachment 38 with corresponding female couplings 39, 40 and 41. The last-mentioned attachment comprises a plate-like bar part 42 in which the quick couplings are applied in recesses in the same way as the quick-coupling parts in the first attachment. The fastenings for this attachment are provided with spring elements (spring cushions) 43, 44 which, upon coupling, permit a certain adaptability in each coupling event so that wear of the quick couplings can be avoided.

Figure 5 shows, from the front, the application of the attachment 45 between transverse bare/transverse beams 46, 47 on equipment 341. A corresponding arrangement is found on the first unit. The attachment is arranged on a bracket 48. In the illustrative embodiment, the attachment is applied using nuts 49 and screws in a known manner. Other forms of fastening (e.g. welding) can also be utilized. The attachment supports/bears quickcoupling parts in accordance with the above. 35 A number of attachments, e.g. two attachments 45, 451, can be applied in the equipment and the vehicle, having the same attachment arrangement as above. Two spaces U, U' are shown for the attachments 45, 451 in Figure 5, which also shown lower and upper beams 461, 471 extending in the width direction.

Figure 6 shows in principle a cone-shaped control function with a conical plug 50 in the vehicle and a corresponding cone-shaped control recess 51 in the equipment (or vice versa). One, two or more such cone shaped control functions can be arranged in order to reduce the wear of the quick couplings.

Figure 7 shows a hydraulics system 52 for operating outlined components 53, 54 in the equipment.

Any overpressure which occurs in the system can be eliminated via the quick-coupling function in accordance with the above. In an alternative or complementary embodiment, an elimination function in the form of pressure -puncturing member 55 can be used in the vehicle.

Upon mechanical coupling of vehicle and equipment, the member 55 comes into cooperation with a valve member 56 having, or in the form of, an activation part. The work medium/hydraulic oil can in this case leak out via discharge line 57 and down into a sump 58. After pressure elimination has thus been achieved, the activation between the member 55 and the activation part 56 ceases, e.g. by means of the member 55 being turned away. As an alternative, the part 56 can be arranged to effect pressure elimination for a certain position of activation from the member 55. When this position of activation is passed, the discharge line to the sump is closed off.

Pressure elimination thus at all times takes place in the event of possible overpressure during uncoupling. When the vehicle and the equipment are uncoupled, the valve 56 which can spring back returns to its starting position.

The discharge of overpressure medium takes place via a unit 59 which, as an alternative or as a complement, can be activated manually, e.g. can be opened and closed manually in accordance with a known principle. In Figure 7 the quick-coupling functions are shown by 60, 61. In the illustrative embodiment, said pressure elimination function is arranged in the return system/line 62.

Depending on the mode of operation of the components, the puncturing function(s) can be arranged alternatively or as a complement in the feed lines 63 and/or 64.

Figures 8, 8a and 8b show an arrangement for an easily removable attachment 64 which has quick couplings 65, 66 in accordance with the above. The attachment is applied removably in a bearing part 67 which is secured or can be secured in the first or second unit. The attachment can be pushed down at its one end 64a in a recess 67a formed with a U-shaped part 67b on the part 67, which at its other end has a recess 67c. The attachment can engage in this recess via a curved part or plug 64b. The attachment 64 and the part 67b as well as a part 67d opposite the part 67b are, in addition to the part 64a on the attachment, provided with through-holes 67d, 67f and 64c in which a locking member 68 with engagement part and handle can be engaged and locked. In this way the attachment can be easily applied and anchored to the bearing part and can be removed using simple and manual procedures. This arrangement is particularly useful when coupling using fully or partially manual procedures for quick couplings. The attachment can be designed in different alternatives with respect to the male coupling(s), female coupling(s), number of couplings, type of couplings, size of couplings, etc. The attachment can in this case be bought in separately in accordance with the desired actual case.

According to Figure 9, a separate intermediate part 69 can be used for coupling the first and second units. The intermediate part has quick-coupling units 72, 73 compatible with corresponding quick-coupling units 74, 75 on the first and second units, respectively. Control functions (not shown) in accordance with the above can also be used in one or both parts. In this case too it is possible to interchange and choose between different quick-coupling configurations. Different variants of intermediate coupling parts can be made. The intermediate coupling part is characterized by members or arrangements which are designed with male and/or female coupling formations at both ends in order to fit the female and/or male coupling parts in the units 70 and 71. The is - intermediate part can also be regarded as an adapter unit when it comes to coupling together quick-coupling parts of different designs in the first and second units.

In a further embodiment, the intermediate part serves as a fixture or centering part when mounting the attachments and quick-coupling parts in the first and second units. The parts 72, 74 and 73, 75, respectively, inthis case form centering parts, with the result that the parts 74, 75 are mutually centered or lined up. After such centering, the attachments/quick-coupling parts can finally be made secure after having been fixed in a displaceable (laterally displaceable) manner in an initial stage.

Figure 10 shows equipment with quick-coupling is parts (male and/or female parts) 77 for manual coupling with corresponding quick-coupling parts on the first unit, the attachment 64in accordance with the above and/or the intermediate part 69 in accordance with the above.

The invention is not limited to the embodiments shown, and instead can be modified in accordance with the claims and description.

Claims

PATENT CLAIMS

1. An arrangement for ensuring the possibility of coupling a first mobile unit, e.g. a truck, loader, etc., to a second unit, e.g. equipment (such as sweeping or cutting appliances), which is used by the first unit, where the possibility of coupling includes, in addition to mechanical coupling of the first and second units, also automatic and/or mechanical hydraulic coupling via a quick-coupling function in said first and second units, which are provided respectively with male and female coupling part (a) included in the quick-coupling function, wherein one or both of said units is/are arranged with pressure- eliminating members which come into operation upon said automatic and/or mechanical coupling for the is quick-coupling function and, when there is an overpressure prevailing in the hydraulic system or hydraulic circuit of the second unit, eliminate this overpressure, it being possible for the last-mentioned coupling to be carried out counter to overpressure in the hydraulic system or the hydraulic circuit.

2. The arrangement as claimed in Patent Claim 1, wherein at least one part in each pair of male and female parts In the two units in provided with a pressure eliminator which can be activated by the second part in said respective pair of male and female coupling parts upon the automatic and/or mechanical coupling for the quick-coupling function, which pressure eliminator eliminates an overpressure prevailing in said one part and/or in the hydraulic system or hydraulic circuit which in/are connected to the one part.

3. The arrangement as claimed in Patent Claim 1 or 2, wherein the coupling of the hydraulic system and the coupling-in of the hydraulic circuit is arranged to take place essentially free from spillage via said quickcoupling parts.

4. The arrangement as claimed in any one of the preceding patent claims, wherein the quick-coupling parts are arranged with a mutual eel f-holding function which is activated upon automatic coupling and brings about mechanical locking of the cluick-coupling parts to each other.

The arrangement as claimed in any one of the preceding patent claims, wherein the male or female parts in one or more pairs of quick couplings are arranged in an attachment in the first unit, and the corresponding female and male coupling parts in said one or more pairs of quickcoupling parts are arranged in a second attach- ment in the second unit.

6. The arrangement as claimed in either of Patent Claims 4 and 5, wherein the mechanical locking of the quick-coupling parts to one another prevents separating forces occurring between the attachments in the event of is variable pressure in the lines to the quick-coupling parts.

7. The arrangement as claimed in Patent Claim 4, 5 or 6, wherein the first attachment also comprises one or more parts on one or more quick-couplings for electric- ity, and the second attachment has a part or parts of the quick- coupling (a) for electricity which can cooperate with each of said parts.

8. The arrangement as claimed in Patent Claim 5 or 6, wherein the attachment with associated quick-coupling parts in placed low in the mechanical coupling arrange ment so that there in a clear view from the driver's cab of the first unit.

9. The arrangement as claimed in any one of the preceding patent claims, wherein upon coupling of the first and second units, one or more conical plugs islare arranged to ensure a control function which reduces wear due to coupling of the coupling parts.

10. The arrangement an claimed in any one of the preceding patent claims, wherein quick-coupling parts cooperating with each other can be allocated optional placings in the first and second attachments in order, in the case of two or more pairs of quick-coupling parts on the first and second attachments, to prevent the risk of mix-up upon coupling of said two or more pairs of quick- coupling parts, where, for example, in a first pair of quick-coupling parts the male part is placed on the first attachment and the female part is placed on the second attachment, and in a second pair of quick- coupling parts the female part is placed on the first attachment and the male part is placed on the second attachment.

11. The arrangement as claimed in any one of the preceding patent claims, wherein each coupling works with two double-acting hydraulic functions and with one to six electrical functions, together with a line for the electricity.

12.

positive return The arrangement as claimed in any one of the preceding patent claims, wherein the first and/or the second attachments islare secured in a resilient manner is in the first and second units, respectively.

13. The arrangement as claimed in any one of the preceding patent claims, wherein the first and/or the second attachment is/are arranged adjacent to a free space/free spaces in the mechanical coupling arrangement.

14. The arrangement as claimed in any one of the preceding patent claims, wherein the first and/or the second attachment is/are arranged between outerf upper and lower frame beams or bar elements present on the first unit and second unit, respectively.

15. The arrangement as claimed in any one of the preceding patent claims, wherein each hydraulic quickcoupling is arranged to close off the work medium in the event of unintentional uncoupling of the first and second units.

16. The arrangement as claimed in any one of the preceding patent claims, wherein one or more quickcoupling parts is/are arranged for manual coupling in those cases where they are placed on the first and/or second unit without associated attachment.

17. The arrangement as claimed in any one of the preceding patent claims, wherein in each pair of quickcouplings for the hydraulics, both the male part and female part have pressure- eliminating members, the one coupling part in the pair has a longitudinally displaceable inner sleeve which has at its outer end a projecting part which extends essentially parallel to an activation section in the second coupling part of the pair when the male and f emale parts of the pair are pushed together, and, at its part allowing working medium through, the inner sleeve is mounted on a longitudinally displaceable valve body in the one part.

18. The arrangement as claimed in any one of the preceding patent claims, wherein the work medium can be conveyed through said projecting and activation parts, and the pressure eliminator in said one part is arranged behind said inner sleeve.

19. The arrangement as claimed in any one of the preceding patent claims, wherein the second part is is arranged with a volume-swallowing function, and the pressure eliminator of the second part is arranged behind the volume-swallowing function.

20. The arrangement an claimed in any one of the preceding patent claims, wherein the male and female coupling parts in each quick coupling operate with a ball-locking arrangement with a ball race which is displaceable relative to the one coupling part in the quick coupling, the ball race is displaceable relative to the frame of the one part by means of an external control function which in effected by an activation member and which acts on the ball race relative to the frame, and, when the coupling parts are brought fully together, the ball race is acted on relative to the frame to a first position where the balls of the ball race drop down, in cooperation with the frame of the other coupling part, into one or more recesses in the last-mentioned frame, and the ball race is then acted on relative to the frame to a second position in which the balls are held down in the recesses by means of the ball race, and in this way there is mutual locking between the male and female coupling parts, and, upon uncoupling, the external control function comes into play and causes displacement of the ball race relative to the frame to the first position in which the balls can leave said recesses in - 2Q - order to terminate the locking function, and furthermore to a starting position relative to the frame in which the balls have left the recesses and the locking function has in this way be cancelled.

21. The arrangement as claimed in Patent Claim 20, wherein the ball race in arranged to keep the balls pressed down in the respective recess even if a slight longitudinal displacement movement occurs in the ball race relative to the quick-coupling part concerned, e.g.

the female part.

22. The arrangement as claimed in any one of the preceding patent claims, wherein the arrangement includes a manually removable attachment which is preferably connected to a bearing part on the first and/or to an is intermediate part and has parts which can be applied in recesses, and where the attachment and the bearing part can preferably be locked to each other by means of a locking member.

23. The arrangement as claimed in any one of Patent Claims 1 - 21, wherein the coupling or centering of the first and second units can be carried out via or with an intermediate part or f ixture which has quick-coupling parts or centering parts which are compatible and can cooperate in a centering function with corresponding quick-coupling parts and centering parts in the first andlor the second unit.