EP0046214B1 - Control appliance for the hydraulically operated scraper blade attached to a snow removal equipment - Google Patents

Control appliance for the hydraulically operated scraper blade attached to a snow removal equipment Download PDF

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Publication number
EP0046214B1
EP0046214B1 EP81105890A EP81105890A EP0046214B1 EP 0046214 B1 EP0046214 B1 EP 0046214B1 EP 81105890 A EP81105890 A EP 81105890A EP 81105890 A EP81105890 A EP 81105890A EP 0046214 B1 EP0046214 B1 EP 0046214B1
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EP
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Prior art keywords
lifting cylinder
pressure
hydraulic
cylinders
lifting
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EP81105890A
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German (de)
French (fr)
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EP0046214A3 (en
EP0046214A2 (en
Inventor
Alfred Schmidt
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Ing Alfred Schmidt GmbH
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Ing Alfred Schmidt GmbH
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Priority to AT81105890T priority Critical patent/ATE9827T1/en
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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01H—STREET CLEANING; CLEANING OF PERMANENT WAYS; CLEANING BEACHES; DISPERSING OR PREVENTING FOG IN GENERAL CLEANING STREET OR RAILWAY FURNITURE OR TUNNEL WALLS
    • E01H5/00—Removing snow or ice from roads or like surfaces; Grading or roughening snow or ice
    • E01H5/04—Apparatus propelled by animal or engine power; Apparatus propelled by hand with driven dislodging or conveying levelling elements, conveying pneumatically for the dislodged material
    • E01H5/06—Apparatus propelled by animal or engine power; Apparatus propelled by hand with driven dislodging or conveying levelling elements, conveying pneumatically for the dislodged material dislodging essentially by non-driven elements, e.g. scraper blades, snow-plough blades, scoop blades

Definitions

  • the invention relates to a control device with an electrically or hydraulically controllable hydraulic control valve for the hydraulic actuation of a snow plow attached to a clearing vehicle, the ploughshare of which is connected via a handlebar parallelogram to a device plate attached to the vehicle and can be actuated by means of hydraulic cylinders supported between the device plate and the ploughshare, of which a centrally located lifting cylinder for the lifting / lowering movement and two side-mounted diverter cylinders for the right / left pivoting of the ploughshare are provided.
  • a snow plow of the specified type has become known through the advertising letter "Multi-share spring plows type MF" from Ing. Alfred Schmidt GmbH from June 1975, the control being carried out via a switching device arranged in the interior of the driver's cab. Regarding such control devices, reference is made to US-A-4 028 820.
  • the invention is based on the object of designing a control device of the type mentioned at the outset in such a way that when the ploughshare which is always horizontal is raised and lowered, a certain pivoting position of the ploughshare in relation to a vertical axis of rotation can be maintained or lowering a tension in the articulation elements, in particular blocking the changeover cylinder, automatically, d. H. without intervention by the driver.
  • control valve can be controlled to avoid kinematic constraints when lifting or lowering depending on the pressure in the lifting cylinder and after a pressure increase in the lifting cylinder up to a predetermined upper liquid pressure, the hydraulic lines to the two changeover cylinders with one leading to a liquid container Return line connects and which, due to the resulting pressure drop in the lifting cylinder, only interrupts this connection when a predetermined lower liquid pressure in the lifting cylinder is reached.
  • the invention provides that the predetermined upper or lower fluid pressure in the lifting cylinder can be adjusted in a variable manner. It goes without saying within the scope of the invention that the upper liquid pressure is to be chosen lower than that required to unlock the pressure relief valves. ge pressure.
  • control valve as ent is formed lockable check valve, which is switched into a connecting line between the hydraulic lines to the two changeover cylinders and can be switched via a pulse generator controlled by the pressure in the lifting cylinder.
  • the hydraulic control valve can be operated electrically or hydraulically.
  • Fig. 1 shows an oblique top view of the front of a motor vehicle to which a device plate 1 is attached.
  • a handlebar parallelogram consisting of an upper pair of links 2 and a lower pair of links 3 is articulated on the device plate 1.
  • Both pairs of links 2, 3 are each pivotally pivoted about a (not shown) horizontal axis on a vertical pipe section 4, on which a vertical frame part 5 of the ploughshare 6 is suspended pivotably about the longitudinal axis of the pipe section 4.
  • the rear view of the ploughshare shown in the top view like the horizontal frame part 8 connected to it via short webs 7, is shown in a greatly simplified manner for the sake of clarity of the drawing.
  • the two changeover cylinders 9, 10 are articulated on the horizontal frame part 8 so as to be pivotable about vertical axes. These are hinged at their other ends to the device plate 1, pivotable about horizontal axes.
  • a lifting cylinder 11 is articulated, on the one hand, on a pipe bend 12 that raises the device plate, and, on the other hand, on the lower pair of links 3, each pivotable about horizontal axes.
  • the ploughshare 6 is drawn in the extreme right swivel position, in which the right change cylinder 9 is shortened to the maximum, the left, also telescopic change cylinder 10 is extended to the maximum.
  • the control device comprises a hydraulic control valve 18 which, depending on the pressure pulse in the pressure chamber 15 of the lifting cylinder 11, can either be switched hydraulically, as shown in more detail, via an electrical circuit or alternatively, as indicated by a double dashed line H.
  • the electrical circuit comprises a pressure-sensitive pulse generator 19, which is connected on the one hand to the corresponding hydraulic line 16 of the lifting cylinder 11 and on the other hand closes a switch 20 of a circuit S when an upper fluid pressure is reached, as a result of which the hydraulic control valve 18 switches from the illustrated switching position to the switching position 11 becomes.
  • the pulse generator 19 causes an interruption in the circuit S and the control valve returns to its starting position I.
  • the switching process described can be repeated several times during a lifting movement.
  • the intervals with the switching point 11 are so short that there is no fear of the ploughshare 6 tipping over into another swivel position during the pressure relief of the changeover cylinders.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Cleaning Of Streets, Tracks, Or Beaches (AREA)
  • Regulating Braking Force (AREA)

Abstract

1. Control appliance having a control valve (18), which may be controlled electrically or hydraulically, for hydraulically operating a snow plow mounted to a vehicle, the plow share (6) of said plow being connected via a guide parallelogram to an attachment plate (1) which is attached to the vehicle and may be operated by means of hydraulic cylinders which are supported between said attachment plate and said plow share, said hydraulic cylinders comprising a centrally arranged lifting cylinder (11) for the up/down movement and two reversal cylinders (9, 10) arranged laterally for the right/left swivelling of the plow share, characterized in that in order to avoid kinematic restraints upon lifting and moving down, reps., said control valve (18) may be controlled in dependence on the pressure in the lifting cylinder (11) and, after a pressure rise in said lifting cylinder (11) up to a specified upper hydraulic pressure, connects the hydraulic lines (23, 24) to the two reversal cylinders (9, 10) by means of a return line (26) leading to a hydraulic container (27), and, after drop in pressure within the lifting cylinder (11) caused thereby, disconnects in turn this connection only upon reaching a specified lower hydraulic pressure within the lifting cylinder (11).

Description

Die Erfindung betrifft eine Steuervorrichtung mit einem elektrisch oder hydraulisch ansteuerbaren hydraulischen Steuerventil für die hydraulische Betätigung eines an einem Räumfahrzeug angebauten Schneepflugs, dessen Pflugschar über ein Lenkerparallelogramm mit einer am Fahrzeug befestigten Geräteplatte verbunden und mittels zwischen Geräteplatte und Pflugschar abgestützter hydraulischer Zylinder betätigbar ist, von denen ein mittig angeordneter Hubzylinder für die Hebe-/Absenkbewegung und zwei seitlich angebrachte Umstellzylinder für die Rechts-/Linksverschwenkung der Pflugschar vorgesehen sind.The invention relates to a control device with an electrically or hydraulically controllable hydraulic control valve for the hydraulic actuation of a snow plow attached to a clearing vehicle, the ploughshare of which is connected via a handlebar parallelogram to a device plate attached to the vehicle and can be actuated by means of hydraulic cylinders supported between the device plate and the ploughshare, of which a centrally located lifting cylinder for the lifting / lowering movement and two side-mounted diverter cylinders for the right / left pivoting of the ploughshare are provided.

Ein Schneepflug der angegebenen Art ist durch die Werbeschrift »Mehrschar-Federpflüge Typ MF« der Firma Ing. Alfred Schmidt GmbH vom Juni 1975 bekanntgeworden, wobei die Steuerung über eine im Inneren des Fahrerhauses angeordnete Schaltvorrichtung erfolgt. Bezüglich solcher Steuervorrichtungen wird auf die US-A-4 028 820 hingewiesen.A snow plow of the specified type has become known through the advertising letter "Multi-share spring plows type MF" from Ing. Alfred Schmidt GmbH from June 1975, the control being carried out via a switching device arranged in the interior of the driver's cab. Regarding such control devices, reference is made to US-A-4 028 820.

Wird die Pflugschar in einer bestimmten Schwenklage über den Hubzylinder an dem ihn abstützenden Lenkerparallelogramm angehoben, so kommt es insbesondere im oberen Hubbereich und im unteren Senkbereich zu mechanischen und hydraulischen Verspannungen in den Umstellzylindern, solange deren Druckleitungen gesperrt sind, um die bestimmte Schwenklage der Pflugschar aufrechtzuerhalten. Derartige Verspannungen können nicht durch konstruktive Maßnahmen vermieden werden. Es kann zu so starken Verspannungen in den Anlenkorganen kommen, daß das Gerät beschädigt, bzw. der Hubvorgang durch ein mit dem Hubzylinder verbundenes Überdruckventil vorzeitig unterbrochen wird.If the ploughshare is raised in a certain swivel position via the lifting cylinder on the handlebar parallelogram supporting it, mechanical and hydraulic tension occurs in the changeover cylinders, especially in the upper lifting area and in the lower lowering area, as long as their pressure lines are blocked in order to maintain the specific swivel position of the plow share . Such tension cannot be avoided by constructive measures. There may be strong tension in the articulation elements that the device is damaged or the lifting process is prematurely interrupted by a pressure relief valve connected to the lifting cylinder.

Es gibt aber Räumaufgaben, die es notwendig machen, daß während des Hebens der Pflugschar die Umstellzylinder für die Seitenverstellung eine bestimmte Schwenklage der Pflugschar aufrechterhalten, so z. B. beim Anhäufen von Schnee. Dieses Bestreben ist offenbar unvereinbar mit der oben erläuterten Erscheinung, wonach es bei gleichzeitiger Betätigung des Hubzylinders und der Umstellzylinder infolge ihrer unterschiedlichen Bewegungsradien zu einer Bewegungssperre mit der Folge eines entsprechenden Druckanstiegs in den Hydraulikzylindern kommen kann. Wollte der Fahrer eines Schneepflugs vermeiden, daß die Pflugschar während des Anhebens unter der Einwirkung der Schneelast unkontrolliert zur Seite hin umklappt, so blieb ihm nur die Möglichkeit, den Bewegungsablauf mehrmals zu unterbrechen, d. h. die Umstellzylinder in gewissen Phasen der Hubbewegung kurzzeitig zu entsperren. Diese Art der Bedienung ist nicht nur umständlich; sie ist für den unerfahrenen Fahrer auch schwierig. In jedem Fall bedeutet sie eine unerwünschte Verzögerung des Arbeitsvorgangs und eine erhebliche Beschädigungsgefahrfür das Gerät.However, there are clearing tasks that make it necessary for the changeover cylinders for the lateral adjustment to maintain a certain swivel position of the ploughshare during the lifting of the ploughshare. B. when snow accumulates. This endeavor is apparently incompatible with the phenomenon described above, according to which a simultaneous actuation of the lifting cylinder and the changeover cylinder can result in a movement lock with the consequence of a corresponding increase in pressure in the hydraulic cylinders due to their different movement radii. If the driver of a snow plow wanted to avoid that the ploughshare fell over to the side in an uncontrolled manner under the influence of the snow load, the only option left to him was to interrupt the sequence of movements several times. H. Unlock the changeover cylinder briefly in certain phases of the lifting movement. This type of operation is not only cumbersome; it is also difficult for the inexperienced driver. In any case, it means an undesirable delay in the work process and a considerable risk of damage to the device.

Demgegenüber liegt der Erfindung die Aufgabe zugrunde, eine Steuervorrichtung der eingangs genannten Art so auszubilden, daß beim »Heben« und »Senken« der stets horizontal liegenden Pflugschar eine bestimmte Schwenklage der Pflugschar bezogen auf eine vertikale Drehachse aufrechterhalten werden kann, wobei während des Hub- bzw. Senkvorgangs eine Verspannung in den Anlenkorganen, insbesondere ein Blockieren der Umstellzylinder, automatisch, d. h. ohne Eingreifen durch den Fahrer, vermieden wird.In contrast, the invention is based on the object of designing a control device of the type mentioned at the outset in such a way that when the ploughshare which is always horizontal is raised and lowered, a certain pivoting position of the ploughshare in relation to a vertical axis of rotation can be maintained or lowering a tension in the articulation elements, in particular blocking the changeover cylinder, automatically, d. H. without intervention by the driver.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß das Steuerventil zur Vermeidung kinematischer Zwängungen beim Heben bzw. Senken abhängig vom Druck im Hubzylinder ansteuerbar ist und nach einem Druckanstieg im Hubzylinder bis zu einem vorgegebenen oberen Flüssigkeitsdruck die Hydraulikleitungen zu den beiden Umstellzylindern mit einer zu einem Flüssigkeitsbehälter führenden Rücklaufleitung verbindet und welches nach dadurch bedingtem Druckabfall im Hubzylinder diese Verbindung erst bei Erreichen eines vorgegebenen unteren Flüssigkeitsdrucks im Hubzylinder wieder unterbricht.This object is achieved in that the control valve can be controlled to avoid kinematic constraints when lifting or lowering depending on the pressure in the lifting cylinder and after a pressure increase in the lifting cylinder up to a predetermined upper liquid pressure, the hydraulic lines to the two changeover cylinders with one leading to a liquid container Return line connects and which, due to the resulting pressure drop in the lifting cylinder, only interrupts this connection when a predetermined lower liquid pressure in the lifting cylinder is reached.

Das Wesentliche dieser erfindungsgemäßen Lösung besteht darin, daß der im Hubzylinder auftretende Druckanstieg als Steuerimpuls für die Betätigung des Steuerventils verwendet wird. Die damit geschaffene Steuervorrichtung ist somit empfindlich für eine Verspannung in nur einem oder in beiden Umstellzylindern. In dem Augenblick, in dem das Steuerventil aufgrund eines derartigen Impulses die Umstellzylinder mit einer zum Flüssigkeitsbehälter führenden Rücklaufleitung verbindet, werden die Umstellzylinder kurzzeitig druckentlastet. Infolge dieser Druckentlastung sinkt auch sofort der Flüssigkeitsdruck im Hubzylinder in den Normalbereich ab, wodurch das Steuerventil wieder in die Ausgangslage zurückschaltet, in welcher es die zu den Umstellzylindern führenden Hydraulikleitungen sperrt. Je nach Ausmaß der Hubbewegung kann dieser Entlastungsvorgang sich während des Anhebens des Schneepflugs mehrfach wiederholen. Der gesamte Vorgang läuft automatisch ab, ist also unabhängig von der Geschicklichkeit des Fahrers.The essence of this solution according to the invention is that the pressure increase occurring in the lifting cylinder is used as a control pulse for the actuation of the control valve. The control device thus created is therefore sensitive to tension in only one or in both changeover cylinders. The moment the control valve connects the changeover cylinders to a return line leading to the liquid container due to such a pulse, the changeover cylinders are briefly relieved of pressure. As a result of this pressure relief, the liquid pressure in the lifting cylinder immediately drops into the normal range, as a result of which the control valve switches back to the starting position in which it blocks the hydraulic lines leading to the changeover cylinders. Depending on the extent of the lifting movement, this relief process can be repeated several times during the lifting of the snow plow. The entire process runs automatically, so it is independent of the skill of the driver.

Um die Steuervorrichtung an den jeweiligen Betriebsdruck des am Fahrzeug vorhandenen Hydrauliksystems oder an die Auslegung der den einzelnen Hydraulikzylindern zugeordneten Überdruckventile anpassen zu können, sieht die Erfindung vor, daß der vorgegebene obere bzw. untere Flüssigkeitsdruck im Hubzylinder veränderbar einstellbar ist. Dabei versteht es sich im Rahmen der Erfindung von selbst, daß der obere Flüssigkeitsdruck niedriger zu wählen ist als der zum Entsperren der Überdruckventile notwendi-. ge Druck.In order to be able to adapt the control device to the respective operating pressure of the hydraulic system present on the vehicle or to the design of the pressure relief valves assigned to the individual hydraulic cylinders, the invention provides that the predetermined upper or lower fluid pressure in the lifting cylinder can be adjusted in a variable manner. It goes without saying within the scope of the invention that the upper liquid pressure is to be chosen lower than that required to unlock the pressure relief valves. ge pressure.

Eine bevorzugte Ausführungsform der Erfindung besteht darin, daß das Steuerventil als entsperrbares Rückschlagventil ausgebildet ist, welches in eine Verbindungsleitung zwischen den Hydraulikleitungen zu den beiden Umstellzylindern eingeschaltet und über einen durch den Druck im Hubzylinder angesteuerten Impulsgeber schaltbar ist. Das hydraulische Steuerventil kann dabei elektrisch oder hydraulisch betätigt werden.A preferred embodiment of the invention is that the control valve as ent is formed lockable check valve, which is switched into a connecting line between the hydraulic lines to the two changeover cylinders and can be switched via a pulse generator controlled by the pressure in the lifting cylinder. The hydraulic control valve can be operated electrically or hydraulically.

Im folgenden wird ein Ausführungsbeispiel der Erfindung anhand der Zeichnung erläutert. Es zeigt

  • Fig. 1 eine vereinfachte perspektivische Darstellung der Aufhängung des Schneepflugs an einem Fahrzeug, und
  • Fig. 2 einen hydraulischen Schaltplan.
In the following an embodiment of the invention is explained with reference to the drawing. It shows
  • Fig. 1 is a simplified perspective view of the suspension of the snow plow on a vehicle, and
  • Fig. 2 is a hydraulic circuit diagram.

Fig. 1 zeigt in schräger Draufsicht die Frontseite eines Kraftfahrzeugs, an welcher eine Geräteplatte 1 befestigt ist. An der Geräteplatte 1 ist ein Lenkerparallelogramm, bestehend aus einem oberen Lenkerpaar 2 und einem unteren Lenkerpaar 3 angelenkt. Beide Lenkerpaare 2, 3 sind jeweils um eine (nicht gezeichnete) horizontale Achse schwenkbar an einem vertikalen Rohrstück 4 angelenkt, an dem ein vertikales Rahmenteil 5 der Pflugschar 6 um die Längsachse des Rohrstücks 4 schwenkbar aufgehängt ist. Die in der Draufsicht dargestellte Rückseite der Pflugschar ist ebenso wie das mit ihr über kurze Stege 7 verbundene horizontale Rahmenteil 8 der besseren Übersichtlichkeit der Zeichnung wegen stark vereinfacht dargestellt. Am horizontalen Rahmenteil 8 sind die beiden Umstellzylinder 9, 10, um vertikale Achsen schwenkbar angelenkt. Diese sind mit ihren anderen Enden an der Geräteplatte 1, um horizontale Achsen schwenkbar, angelenkt. Ein Hubzylinder 11 ist einerseits an einem die Geräteplatte überhöhenden Rohrbogen 12 andererseits am unteren Lenkerpaar 3, jeweils um horizontale Achsen schwenkbar, angelenkt. Die Pflugschar 6 ist in der äußerst rechten Schwenkstellung gezeichnet, bei welcher der rechte Umstellzylinder 9 maximal verkürzt, der linke, ebenfalls teleskopisch ausgebildete Umstellzylinder 10 maximal verlängert ist.Fig. 1 shows an oblique top view of the front of a motor vehicle to which a device plate 1 is attached. A handlebar parallelogram consisting of an upper pair of links 2 and a lower pair of links 3 is articulated on the device plate 1. Both pairs of links 2, 3 are each pivotally pivoted about a (not shown) horizontal axis on a vertical pipe section 4, on which a vertical frame part 5 of the ploughshare 6 is suspended pivotably about the longitudinal axis of the pipe section 4. The rear view of the ploughshare shown in the top view, like the horizontal frame part 8 connected to it via short webs 7, is shown in a greatly simplified manner for the sake of clarity of the drawing. The two changeover cylinders 9, 10 are articulated on the horizontal frame part 8 so as to be pivotable about vertical axes. These are hinged at their other ends to the device plate 1, pivotable about horizontal axes. A lifting cylinder 11 is articulated, on the one hand, on a pipe bend 12 that raises the device plate, and, on the other hand, on the lower pair of links 3, each pivotable about horizontal axes. The ploughshare 6 is drawn in the extreme right swivel position, in which the right change cylinder 9 is shortened to the maximum, the left, also telescopic change cylinder 10 is extended to the maximum.

Beim Anheben der Pflugschar 6 aus der gezeichneten, auf den Boden abgesenkten Lage unter Beibehaltung der gezeichneten Schwenkstellung, wobei die beiden Umstellzylinder 9, 10, druckbeaufschlagt sind, wird der Hubzylinder 11 verkürzt, wodurch die Lenkerpaare 2, 3 nach oben schwenken und die Pflugschar entsprechend anheben. Da hierbei die Anlenkpunkte 13, 14 der beiden Umstellzylinder 9, 10 am horizontalen Rahmenteil 8 der Pflugschar 6 von der durch das Lenkerparallelogramm geführten Kreisbewegung abweichende Kreisbahnen beschreiben, kommt es bei Aufrechterhaltung der Druckbeaufschlagung in den UmstellzylindeTn 9, 10 zu einer Verspannung sämtlicher Anlenkorgane. Diese Verspannung nimmt mit zunehmender Hubhöhe zu und belastet besonders den ausgefahrenen teleskopischen Umstellzylinder 10. Je mehr sich die Anlenkorgane sperren, desto höher wird der doppelt wirkende Hubzylinder 11 belastet, wobei der Druck im druckbeaufschlagten Druckraum 15 des Hubzylinders 11 entsprechend ansteigt. Beim Erreichen eines vorgegebenen oberen Drucks, der jedoch noch unterhalb des Ansprechdrucks des in der zugeordneten Hydraulikleitung 16 eingebauten Überdruckventils 17 ist, wird eine im Hydraulikplan gemäß Fig.2 schematisch dargestellte Steuervorrichtung betätigt, die einen kurzzeitigen Druckabbau in den Umstellzylindern 9, 10 bewirkt. Dadurch kommt es zu einer kinematischen Anpassung der Umstellzylinder an die momentane Geometrie der Hubbewegung, was augenblicklich zu einem Druckabfall im Hubzylinder 11 führt.When lifting the ploughshare 6 from the drawn, lowered position on the floor while maintaining the swivel position shown, the two changeover cylinders 9, 10 being pressurized, the lifting cylinder 11 is shortened, whereby the handlebar pairs 2, 3 pivot upwards and the plow share accordingly lift. Since here the articulation points 13, 14 of the two changeover cylinders 9, 10 on the horizontal frame part 8 of the ploughshare 6 describe circular paths deviating from the circular movement guided by the handlebar parallelogram, maintaining the pressurization in the changeover cylinder T n 9, 10 leads to a tensioning of all articulation elements . This tension increases with increasing lifting height and particularly stresses the extended telescopic changeover cylinder 10. The more the articulation elements block, the higher the double-acting lifting cylinder 11 is loaded, the pressure in the pressurized pressure chamber 15 of the lifting cylinder 11 increasing accordingly. When a predetermined upper pressure is reached, which, however, is still below the response pressure of the pressure relief valve 17 installed in the associated hydraulic line 16, a control device which is shown schematically in the hydraulic diagram according to FIG. 2 is actuated, which causes a brief pressure reduction in the changeover cylinders 9, 10. This results in a kinematic adaptation of the changeover cylinder to the current geometry of the lifting movement, which immediately leads to a pressure drop in the lifting cylinder 11.

Die Steuervorrichtung umfaßt ein hydraulisches Steuerventil 18, welches abhängig vom Druckimpuls im Druckraum 15 des Hubzylinders 11 entweder, wie näher dargestellt, über eine elektrische Schaltung oder alternativ, wie mit einer doppelt gestrichelten Linie H angedeutet, hydraulisch geschaltet werden kann. Die elektrische Schaltung umfaßt einen druckempfindlichen Impulsgeber 19, der einerseits mit der entsprechenden Hydraulikleitung 16 des Hubzylinders 11 verbunden ist und bei Erreichen eines oberen Flüssigkeitsdrucks andererseits einen Schalter 20 eines Stromkreises S schließt, wodurch das hydraulische Steuerventil 18 aus der gezeichneten Schaltstellung in die Schaltstellung 11 geschaltet wird. In der Schaltstellung 11 sind die Verbindungsleitungen 21, 22 des hydraulischen Steuerventils 18 mit den zu den Umstellzylindern 9,10 führenden Hydraulikleitungen 23, 24 auf »Durchgang« geschaltet und über die Ventilabzweigung 25 mit einer Rücklaufleitung 26, die zu einem Flüssigkeitsbehälter 27 für Vorratsflüssigkeit führt, verbunden. Während der Aufrechterhaltung der Verbindung zum Flüssigkeitsbehälter 27, was nur für ein sehr kurzes Zeitintervall der Fall ist, sind die Umstellzylinder drucklos, wobei sie sich in ihrer Ausfahrlänge an die Kinematik der Hubbewegung anpassen. Diese Anpassung erfolgt ohne Unterbrechung des Hubvorgangs durch den Hubzylinder 11, in dessen Druckraum 15 nun wieder ein normaler Arbeitsdruck herrscht, da der Widerstand durch die Umstellzylinder weggefallen ist. Gleichzeitig verursacht der Impulsgeber 19 eine Unterbrechung des Stromkreises S und das Steuerventil geht wieder in seine Ausgangsstellung I zurück. Der geschilderte Schaltvorgang kann sich während einer Hubbewegung mehrfach wiederholen. Die Intervalle mit der Schaltstelle 11 sind dabei so kurz, daß ein Umkippen der Pflugschar 6 in eine andere Schwenkstellung während der Druckentlastung der Umstellzylinder nicht zu befürchten ist.The control device comprises a hydraulic control valve 18 which, depending on the pressure pulse in the pressure chamber 15 of the lifting cylinder 11, can either be switched hydraulically, as shown in more detail, via an electrical circuit or alternatively, as indicated by a double dashed line H. The electrical circuit comprises a pressure-sensitive pulse generator 19, which is connected on the one hand to the corresponding hydraulic line 16 of the lifting cylinder 11 and on the other hand closes a switch 20 of a circuit S when an upper fluid pressure is reached, as a result of which the hydraulic control valve 18 switches from the illustrated switching position to the switching position 11 becomes. In the switching position 11, the connecting lines 21, 22 of the hydraulic control valve 18 with the hydraulic lines 23, 24 leading to the changeover cylinders 9, 10 are switched to "passage" and via the valve branch 25 with a return line 26 which leads to a liquid container 27 for storage liquid , connected. While the connection to the liquid container 27 is being maintained, which is only the case for a very short time interval, the changeover cylinders are depressurized, and their extension length adapts to the kinematics of the lifting movement. This adjustment takes place without interruption of the lifting process by the lifting cylinder 11, in the pressure chamber 15 of which a normal working pressure now prevails again, since the resistance due to the changeover cylinder has disappeared. At the same time, the pulse generator 19 causes an interruption in the circuit S and the control valve returns to its starting position I. The switching process described can be repeated several times during a lifting movement. The intervals with the switching point 11 are so short that there is no fear of the ploughshare 6 tipping over into another swivel position during the pressure relief of the changeover cylinders.

Claims (3)

1. Control appliance having a control valve (18), which may be controlled electrically or hydraulically, for hydraulically operating a snow plow mounted to a vehicle, the plowshare (6) of said plow being connected via a guide parallelogram to an attachment plate (1) which is attached to the vehicle and may be operated by means of hydraulic cylinders which are supported between said attachment plate and said plowshare, said hydraulic cylinders comprising a centrally arranged lifting cylinder (11) for the up/ down movement and two reversal cylinders (9, 10) arranged laterally for the right/left swivelling of the plowshare, characterized in that in order to avoid kinematic restraints upon lifting and moving down, reps., said control valve (18) may be controlled in dependence on the pressure in the lifting cylinder (11) and, after a pressure rise in said lifting cylinder (11) up to a specified upper hydraulic pressure, connects the hydraulic lines (23, 24) to the two reversal cylinders (9, 10) by means of a return line (26) leading to a hydraulic container (27), and, after drop in pressure within the lifting cylinder (11) caused thereby, disconnects in turn this connection only upon reaching a specified lower hydraulic pressure within the lifting cylinder (11).
2. Control appliance according to claim 1, characterized in that the specified upper or lower hydraulic pressure resp., within the lifting cylinder (11) may be adjusted variably.
3. Control appliance according to claim 1 or 2, characterized in that the control valve (18) is adapted to be a non-return valve which may be unlocked, said non-return valve being inserted into a connection line (21) between the hydraulic lines (23, 24) to the two reversal cylinders (9, 10) and may be operated via an impulse generator (19) which is controlled by the pressure within the lifting cylinder (11).
EP81105890A 1980-08-16 1981-07-25 Control appliance for the hydraulically operated scraper blade attached to a snow removal equipment Expired EP0046214B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81105890T ATE9827T1 (en) 1980-08-16 1981-07-25 CONTROL DEVICE FOR THE HYDRAULIC ACTUATION OF A SNOW PLOW MOUNTED TO A PLOW.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3031037A DE3031037C2 (en) 1980-08-16 1980-08-16 Control device for the hydraulic actuation of a snow plow attached to a clearing vehicle
DE3031037 1980-08-16

Publications (3)

Publication Number Publication Date
EP0046214A2 EP0046214A2 (en) 1982-02-24
EP0046214A3 EP0046214A3 (en) 1982-03-10
EP0046214B1 true EP0046214B1 (en) 1984-10-10

Family

ID=6109779

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81105890A Expired EP0046214B1 (en) 1980-08-16 1981-07-25 Control appliance for the hydraulically operated scraper blade attached to a snow removal equipment

Country Status (4)

Country Link
EP (1) EP0046214B1 (en)
AT (1) ATE9827T1 (en)
DE (1) DE3031037C2 (en)
NO (1) NO812764L (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29507623U1 (en) * 1995-05-08 1995-07-20 Gießler, Matthias, Dipl.-Ing. (FH), 77933 Lahr Hydraulic relief device for attachments

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0111882A3 (en) * 1982-12-13 1984-07-25 Ing. Alfred Schmidt Gmbh Snow-plough
GB8505955D0 (en) * 1985-03-07 1985-04-11 Econ Group Plc Mounting of snow ploughs
DE3602758A1 (en) * 1986-01-30 1987-08-20 Daimler Benz Ag Snow plough
DE3932944A1 (en) * 1988-10-06 1990-04-12 Schmidt Alfred Ing Gmbh DEVICE FOR ATTACHING A SNOW PLOW TO A VEHICLE

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH361022A (en) * 1957-08-24 1962-03-31 Schneeraeumungs Maschinen Ag Lifting and swiveling device for a ploughshare that clears one side
US4028820A (en) * 1975-12-31 1977-06-14 Douglas Dynamics Corporation Hydraulic system for vehicle mounted snowplow blade
US4187763A (en) * 1978-03-31 1980-02-12 Gould Inc. Overload relief valve

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29507623U1 (en) * 1995-05-08 1995-07-20 Gießler, Matthias, Dipl.-Ing. (FH), 77933 Lahr Hydraulic relief device for attachments

Also Published As

Publication number Publication date
DE3031037A1 (en) 1982-03-04
DE3031037C2 (en) 1982-11-04
EP0046214A3 (en) 1982-03-10
NO812764L (en) 1982-02-17
ATE9827T1 (en) 1984-10-15
EP0046214A2 (en) 1982-02-24

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