EP0486871B1 - Method for assisting the crushing capacity of demolition apparatus and apparatus used in such method - Google Patents

Abstract

A method of crushing material between cooperating jaws of a crushing jaw assembly of a demolition tool includes the steps of applying a closing force to at least one of the jaws for urging the jaws toward one another; and imparting a vibratory motion to at least one of the jaws while the closing force is applied.

Description

The invention relates to a method for improving the size reduction effect of demolition tools in the form of demolition tongs or scissors and a demolition tool suitable for carrying out the method.

Depending on whether the demolition tool is designed as demolition tongs or demolition shears, it has two pliers jaws or scissor arms that are movable relative to one another and act on the comminution material as tool blades.

The drive unit acting on at least one tool blade, by means of which the required closing force is also generated during the shredding process, can be of any desired design; In the demolition tools manufactured today, it usually consists of one cylinder unit or several cylinder units, with which, if necessary, both tool blades can be driven simultaneously.

DE-C2-33 42 305 discloses a demolition grapple called a concrete crusher with two jaws movably supported on a supporting body, which are each driven by a hydraulically operating cylinder unit.

In contrast to this, the demolition shear described in EP-A2-0218 899 only has a movable pliers arm with a drive unit consisting of a cylinder unit; the second gun arm is immovably attached to the associated support body.

Demolition tools of the type mentioned here (demolition grapple, demolition shears) represent an effective alternative to the hydraulic / pneumatic striking mechanism, the steel bulb or the blasting agent in many cases, particularly when demolishing and renovating buildings. Their advantages lie in particular in the low noise level and the possibility , for example, to shred existing reinforcements and to separate the different building materials resulting from the shredding process from the point of view of reprocessing / reuse.

The previously mentioned embodiments of demolition tools correspond to one another in that they each generate a continuously effective closing force. When crushing concrete or similar building materials with and without reinforcement, there is always the case that in certain work situations the breaking or cutting force exerted by the demolition tool does not lead to the desired result. Accordingly, the more frequent relocation, tracking and rescheduling of the demolition tool may result in a considerable loss of demolition or shredding performance.

Post-published document EP-A-0404229 describes a demolition tool in the form of demolition pliers with two tool blades which can be driven with respect to a supporting body. These are designed in such a way that the closing force acting on the tool blades is at least temporarily superimposed on vibratory movements which are triggered on one of the tool blades each forming a pliers jaw. A toothed carrier is pivotally held on this jaw, which can be moved back and forth relative to the jaw by means of a vibration generator in the form of a cylinder unit and thereby supports the crushing effect emanating from the demolition jaw.

The invention is based on the object of developing a method for improving and / or supporting the crushing action of demolition tools and a demolition tool suitable for carrying out the method, which only trigger vibrations when required and which accordingly have better economic viability than previously conventional embodiments.

The object is achieved by a method having the features of claim 1.

The basic idea of the invention is then to at least temporarily overlay the closing force acting on the tool blades with vibration movements which are only triggered on at least one of the tool blades as soon as the closing force effective between the tool blades has risen to a predetermined, adjustable minimum value.

The tool sheet in question is not immediately used to generate the vibratory movements moved, but indirectly set in vibration - for example via a working device attached to it.

For reasons of economy and to limit noise, the vibrations are only triggered as soon as the closing force between the tool blades has reached the minimum value already mentioned. Only when the expected shredding effect cannot be achieved in normal operation is the demolition process continued with the aforementioned vibration superimposition. If the desired work progress occurs, the closing force temporarily drops below the set minimum value, so that the vibration movements are interrupted. These operations can take place during a work cycle, e.g. H. Repeat several times until the jaw opening of the demolition tool is closed.

In order to prevent the vibration superimposition from being maintained over an unnecessarily long period of time without achieving work progress, it is provided that the vibration movements are interrupted each time after a predetermined, adjustable period of time (claim 2).

In order to rule out undesirable stress on the demolition tool when the tool blades are touching, the method is designed in such a way that the generation of vibratory movements is prevented as soon as the tool blades have approached a predetermined end position in the course of the closing movement (claim 3).

The above-mentioned object is further achieved by a demolition tool designed as demolition pliers or scissors with the features of claim 4 solved. This has a vibration generator which can be switched on during operation of the drive unit for the at least one movable tool blade and via which vibration movements acting on the comminution material at the mouth opening can be triggered. The vibration generator acts on the drive unit of the demolition tool, so that it causes the vibrations of the relevant tool blade, the vibrations being triggered only by actuation of a switching unit, after a parameter - which represents a measure of the stress during the demolition process - on a predetermined, adjustable minimum value has risen. If the demolition tool is operated hydraulically, the operating pressure for the drive unit is particularly suitable as a parameter.

The longest possible duration of the vibration movements can be set by means of a timer which switches on the vibration generator when the parameter increases to the minimum value (claim 5).

In a preferred embodiment of the subject matter of the invention there is a connecting valve controlled by the operating pressure of the drive unit and having a downstream timer via which the pulse generator can be switched on, the energy supply of which can also be interrupted via the timer regardless of the position of the connecting valve (claim 6). If, therefore, the operating pressure does not drop below this after rising to a predetermined minimum value, the pulse generator is nevertheless switched off via the timing element after a predetermined period of time, with the result that the vibration superposition is eliminated.

For safety reasons, a limit switch is assigned to at least one driven tool blade, by means of which the vibration generator is switched off when the tool blade approaches the predetermined end position during the closing movement (claim 7). This prevents vibrating movements from being maintained or triggered by an increase in the parameter in question to the predetermined minimum value if the tool blades abut one another after the closing movement has been completed.

However, the vibration movements can also be triggered by means of at least one striking mechanism, which is supported on a tool blade (claim 8); if necessary, each of the two tool blades can also be equipped with a plurality of striking mechanisms which act on the comminution material in the region of the mouth opening and thereby also indirectly set the tool blades in vibration.

In the simplest case, the striking mechanisms consist of a cylinder unit with a striking piston which, under the action of a pressure medium, can be displaced against the action of a reset. However, the striking mechanisms can also have a reversal for the movement of the striking piston, as is used in hydraulic hammers.

The vibration movements can also be triggered by means of at least one imbalance generator, which is supported on a tool blade (claim 9). Particularly in the case of embodiments with two movable tool blades, the latter are each equipped with an unbalance generator, and preferably in such a way that the force effect emanating from the unbalance generators is related on the shredding material - is directed towards each other.

Accordingly, the demolition tool can also be designed within the framework of the teaching according to the invention such that the comminution material can be vibrated both via the drive unit and via at least one percussion mechanism or an imbalance generator.

The invention is explained in detail below with reference to several exemplary embodiments shown in the drawing, which relate to a demolition tool designed as demolition pliers with two driven pliers jaws.

Fig. 1

in Schrägansicht schematisiert das Zusammenwirken der erfindungsgemäßen Abbruchzange mit einem Hydraulikbagger,

Fig. 2

schematisiert den Aufbau und die Schaltung der in Fig. 1 dargestellten Abbruchzange, deren angetriebene Zangenbacken während des Zerkleinerungsvorgangs ggf. zusätzlich Vibrationsbewegungen ausführen können,

Fig. 3

schematisiert den Aufbau und die Schaltung einer (teilweise dargestellten) Abbruchzange, deren bewegliche Zangenbacken jeweils mit mehreren Schlagwerken ausgestattet sind und über diese ggf. Vibrationsbewegungen ausführen können,

Fig. 4

einen Schnitt nach Linie IV-IV in Fig. 3 durch die rechte Klemmbacke im Bereich der dort angeordneten Schlagwerke, und

Fig. 5

eine Teilansicht einer Zangenbacke, an welcher ein Unwuchterzeuger befestigt ist.

Show it:

Fig. 1

in an oblique view schematically the interaction of the demolition grapple according to the invention with a hydraulic excavator,

Fig. 2

1 schematically shows the structure and the circuitry of the demolition grapple, the driven jaws of which may perform additional vibratory movements during the comminution process,

Fig. 3

schematically the structure and the circuit of a (partly shown) demolition grapple, the movable jaws of which are each equipped with several striking mechanisms and can execute vibratory movements, if necessary,

Fig. 4

a section along line IV-IV in Fig. 3 through the right jaw in the area of the striking mechanism arranged there, and

Fig. 5

a partial view of a jaw, on which an unbalance generator is attached.

1 shows an example of the use of demolition tongs 1 for crushing / destroying a concrete slab 3 held in the subsurface 2, in cooperation with a hydraulic excavator 4.

The demolition grapple 1 has, in a manner known per se, the main components of two driven jaws 5 and 6, which are movably held on a support body 7. This is rotatably attached to a connection bracket 9 via a connection plate 8, which in turn is pivotable with a Excavator boom 10 - consisting essentially of a front swivel arm 11 and a rear support arm 12 - is connected. The latter is held pivotably with respect to the platform 13 of the hydraulic excavator, which also houses the hydraulic unit 14 serving as an energy source; this also enables the demolition grapple 1 to be operated.

The drive unit for actuating the two jaws 5 and 6 consists of two cylinder units 15 and 16, which are articulated via their cylinder housing 15a, 16a and their piston rod 15b, 16b to the support body 7 or to the associated jaw 5 or 6; the latter components are supported outside the region of the piston rods 15b, 16b on the support body via a rotary bearing 5a or 6a and form the variable jaw opening 17 of the demolition tool into which the concrete slab 3 to be crushed protrudes during the demolition process.

In the illustrated embodiment (Fig. 2) each jaw 5 and 6 - seen in the direction of their longitudinal extension and in the direction of the longitudinal axis la of the demolition grapple - two projecting teeth 5b, c and 6b, c, which under the influence of the Cylinder units 15, 16 exert the closing force exerted on the concrete slab 3. As can be seen from the illustration in question, the demolition grapple 1 is essentially symmetrical with regard to the arrangement and design of its main components with respect to the longitudinal axis 1a.

The right jaw 6 has a stop 18 near its pivot bearing 6a; this is arranged with respect to a limit switch 19 fastened to the support body 7 (in the form of a two-position valve) in such a way that it counteracts the action of a return spring 19a - moves into the open position, not shown, as soon as the two jaws 5 and 6 have approached a predetermined end position in the course of the closing movement, that is to say have almost come into contact with one another. The aforementioned adjustment of the limit switch 19 is brought about in that the stop 18 comes to rest against the button 19b of the limit switch in the course of the pivoting movement carried out by the pliers jaw 6 and then moves it (to the right in the drawing).

The commissioning, switching or switching off of the demolition grapple 1 is carried out by means of a 3/2-way valve 20 (three positions, two ways), which is connected on the input side to a hydraulic source 21 or to a pressure-free return line 22 with a return filter 23; the output side is connected with the interposition of a pressure-controlled directional valve 24 via a line 25 to the extension inlet 15c, 16c of the two cylinder units 15, 16 or via a line 26 to the associated inlet inlet 15d, 16d. As long as the Vegeventil 24 occupies the position shown in FIG. 2, the displacement of the 3/2-way valve 20 to the right leads to the fact that the extension inlets 15c, 16c are pressurized via line 25 or the inlet ports 15d, 16d are relieved of pressure via line 26 are the result that a closing force acting on the concrete plate 3 is exerted on the piston rods 15b, 16b and the jaws 5, 6; the jaws of the pliers therefore endeavor to move towards one another against the action of the concrete slab 3.

Starting from the switch-off position of the 3/2-way valve 20 shown, its displacement to the left leads to the retraction inputs 15d, 16d are pressurized via line 26 and the jaws 5, 6 execute an opening movement which enlarges the jaw opening 17. The line 25 has a connecting valve 27 connected in parallel via a line branch 25a, the position of which can be influenced via a control line 27a opening into the line branch 25a - contrary to the effect of an adjustable pretensioning force. In the (not shown) switch-on position, the operating pressure present in the lines 25, 25a acts on the control input 24a of the directional control valve 24, a pressure-controlled timer 28 and a line 29, which can be connected to a pressure-free return 30 via the limit switch 19. As long as the limit switch 19 assumes the indicated blocking position, the connection between the return 30 and the line 29 is interrupted. The latter may therefore - like the timer 28 and the control input 24a - be subjected to the operating pressure.

The cut-in valve 27 is set such that it only switches to the cut-in position after the operating pressure in the lines 25, 25a has risen to a set minimum value, which in turn is a measure of the pressure from the cylinder units 15, 16 via the pliers jaws 5, 6 represents closing force exerted.

The line 25 passes through the interposition of a check valve 31 into a pulse line 32, which can be pulsed with pressure by means of a rotary slide pulse generator 33. The rotary vane pulse generator, which can be driven by means of a hydraulic motor 34, is connected to the second outlet of the directional control valve 24 via an inlet line 35, which is also equipped with a pressure accumulator 36. The feed line 35 continues, with the interposition of a pressure-controlled shut-off valve 37, into a drive line 38 for the hydraulic motor 34. whose return 39 opens into the unpressurized return line 22.

The pressure switch 28 actuates a time switch 41 via a switching line 40, which in turn is connected to the control input 37a of the check valve 37 and to an outlet 42.

As soon as pressure is applied to the timer 41 via the switching line 40, the connection between the lines 40 and 42 is interrupted and at the same time a counting process is initiated, the duration of which can be set. As long as this counting process is not completed, the check valve 37, which is pressurized via its control input 37a, assumes the open position (not shown), so that the hydraulic motor 34 via its drive line 38, if necessary, i. H. with a suitable position of the directional valve 24, is supplied with drive energy. With the end of the counting process, the timer 41 releases the unpressurized outlet 42, with the result that the pressure at the control input 37a drops and the shut-off valve 37 switches into the illustrated shut-off position: since the power supply to the hydraulic motor 34 is interrupted, it becomes during the relevant period effective rotary valve pulse generator 33 switched off.

The displacement of the connecting valve 27 into the connecting position, not shown, also has the consequence that the directional control valve 24 switches to the second position, not shown, in which u. a. with the interposition of the check valve 37, a connection between the lines 25 and 38 is established.

The pressure accumulator 36 serves to compensate for the pressure fluctuations that are deliberately generated during the operation of the rotary slide valve pulse generator 33, and those outside the area of the cylinder units 15, 16 as returning pressure fluctuations are undesirable.

According to the preceding explanations, the pressure switch 28 and the timer 41 form a timer which automatically interrupts or prevents the generation of further pulse-like pressure fluctuations after an adjustable, predetermined period of time, regardless of the position of the connecting valve 27.

The embodiment in question (according to FIG. 2) of the subject matter of the invention works as follows: after the demolition tongs 1 have been put into operation by moving the 3/2-way valve 20 to the right, the normal closing process is initiated by pressurizing the extension inputs 15c, 16c, one of which Pliers jaws 5, 6 exerted, the crushing / destruction of the concrete plate 3 serving closing force. If the action of the pliers jaws does not lead to the desired work progress, the operating pressure in lines 25, 25a and 27a increases, so that the connecting valve 27, which initially occupies the blocking position, finally switches over to the connecting position and thereby the directional control valve 24 into the second operating position, not shown (ie to the right) or under the influence of switches 28 and 41, the shut-off valve 37 moves into the open position. As a result of these processes, the hydraulic motor 34, which is supplied with energy via the lines 25, 38, drives the rotary slide valve pulse generator 33 and deliberately generates pressure fluctuations in the lines 32, 25 and the cylinder units 15, 16 via which the jaws 5, 6 are immediately vibrated. The activation of the hydraulic motor 34 and the rotary slide pulse generator 33 thus leads to the fact that the closing force is temporarily superimposed on vibratory movements, which, if necessary, the termination effect emanating from the pliers jaws supports or improves.

The vibration superimposition remains effective as long as the connection valve 27 - depending on the operating pressure in lines 25, 25a and 27a - assumes the connection position; in any case, however, it is limited in time by the period of time predetermined with the timer 41, after the expiration of which the outlet 42 is released and thus the rotary slide valve pulse generator 33 is stopped by returning the check valve 37 to the shown locked position.

If no work progress can be achieved by triggering vibratory movements within a predetermined period of time, the operator has the option of opening the demolition grapple by actuating the 3/2-way valve 20 and, for example, moving it.

An undesirable stress on the components of the demolition grapple 1 is prevented by moving the limit switch 19 under the action of the stop 18 towards the end of the closing movement into the open position (not shown), as a result of which the line 29 is connected to the unpressurized return 30. The pressurization of the directional control valve 24 and the pressure switch 28 required for triggering the vibration movements is therefore not possible even if the connection valve 27 should assume the connection position due to an increase in the operating pressure.

The advantage of the embodiment in question is that the pliers jaws 5, 6 are temporarily set in vibration directly under the action of the cylinder units 15, 16 and thus, in addition, considerable impulse forces that support the demolition process arise. However, this presupposes that the vibration generator (hydraulic motor 34 and rotary slide pulse generator 33) is designed accordingly.

The demolition pliers shown in FIGS. 3 and 4 initially differ purely in design from the embodiment described above in that both clamping jaws 5 and 6 (essentially only the clamping jaw 6 is shown) only one tooth projecting in the direction of the longitudinal axis la (for example 6b) and are equipped with two striking mechanisms 43 in the area of each tooth; these lie - seen transversely to the plane of the drawing (Fig. 3) - in the area of the tooth at a distance from each other (Fig. 4).

Each hammer mechanism has a piston rod 43a, which can be extended with respect to the jaw of the pliers, together with piston 43b, which, contrary to the action of a return spring 45, moves outwards via a pulse line 44, i. H. is displaceable in the direction of the concrete block 3 to be crushed.

In contrast to the embodiment already described (according to FIG. 2), the extension inputs of the cylinder units - for example the extension input 16c of the cylinder unit 16 - are connected via the line branch 25a and the line 25 to the 3/2-way valve 20 already mentioned. With regard to the cylinder units, this only has the effect that they may perform a closing or opening movement.

The connecting valve 27 also connected to the line branch 25a influences, via a control input 46a, the position of a spring-loaded check valve 46, which in the open position connects the line 25 with the drive line 38 for the hydraulic motor 34, with the inlet line 35 for the rotary valve pulse generator 33 and connects to the pressure accumulator 36.

The rotary vane pulse generator can be used via the already mentioned impulse line 44 drive the striking mechanisms 43 attached to the pliers jaws. The embodiment in question works as follows:
With the actuation of the 3/2-way valve 20 by shifting to the right, the cylinder units are pressurized via the lines 25, 25a in the sense of their extension movement; this leads to the fact that the jaws of the pliers come to rest against the concrete slab 3 to be shredded and bring the closing force caused by the cylinder units into effect there. The striking mechanisms 43 are not in operation during this time, since the blocking valve 46 assumes the blocking position shown in FIG. 3, the rotary slide pulse generator 33 is accordingly not effective and the pulse line is not pressurized. The piston rods 43a and piston 43b assume the retracted rest position indicated in FIG. 4 under the action of the return springs 45.

If the pressurization of the cylinder units does not make any progress, this leads to an increase in the operating pressure in the lines 25, 25a and 27a. When a minimum value specified on the connecting valve 27 is reached, it switches over to the connecting position, not shown, shifts the blocking valve 46 into the open position, not shown, by pressurizing the control input 46a, and thereby switches on the hydraulic motor 34, which in turn drives the rotary valve pulse generator 33. This impacts the striking mechanisms 43 via the impulse line 44 in such a way that their components 43a and 43b execute reciprocating movements. As long as the cut-in valve 27 assumes the cut-in position, the closing force exerted by the pliers jaws will be additionally vibrating movements acting on the concrete slab 3 are superimposed. Since the jaws absorb the impulse forces emanating from the striking mechanisms, they are also indirectly vibrated by them. The connection of the rotary slide pulse generator 33, which is dependent on the working conditions, leads to the fact that otherwise it would not be possible to achieve work progress without moving the demolition grapple.

The last-described embodiment of the subject matter of the invention can - in reference to the embodiment according to FIG. 2 - be advantageously configured in that the connection valve 27 is connected to the check valve 46 with the interposition of the pressure switch 28, the switching line 40, the timer 41 and the outlet 42 . In such a development, the shutoff valve 46 is automatically switched to the illustrated shutoff position after an adjustable, predetermined period of time, independently of the position of the connecting valve 27, whereby the power supply to the hydraulic motor 34 is interrupted.

In the embodiment according to FIG. 5, the vibratory movements of the clamping jaws 5 and 6 (only the clamping jaw 6 is shown as an example) are triggered by means of the unbalance generator 47 attached to the latter. These are arranged and designed in such a way that the force effect emanating from them - in relation to the concrete slab 3 to be crushed (cf. FIG. 3 for example) - is directed in opposite directions to one another.

Deviating from the illustrated embodiments, the demolition grapple can also be designed and switched within the scope of the invention such that it allows several types of vibration superimposition, that is, the pulse-like action on the cylinder units 15, 16 according to FIG. 2 and the action of the crushing material (concrete slab 3) by switching on striking mechanisms or unbalance generators which are attached to the pliers jaws.

Expediently, the two vibration superimpositions can be activated separately from one another, so that they can - depending on the operating conditions - be effective simultaneously or in succession if necessary. If, for example, the vibrating movements of the pliers jaws do not yet make any progress, this can possibly be brought about by switching on or switching on the striking mechanism or unbalance generator.

The method proposed by the invention can also be carried out by hand. A characteristic variable, which represents a measure of the stress on the demolition grapple during the demolition process, is preferably determined and displayed. On the basis of this display, an operator can initiate the vibration superimposition and, if this does not lead to the desired work progress, switch it off after a period that appears to be suitable.

The advantage achieved with the invention can be seen in the fact that the economy of the demolition tool can be increased with an improved size reduction / demolition effect.

The effect sought with the invention can also be different when used designed components for the generation of the vibration movements (drive unit, pulse generator, impact mechanism, unbalance generator) can be brought about.

Claims (9)

1. Method for improving and/or assisting the crushing capacity of demolition apparatus in the form of demolition claws (1) or shears with at least one tool blade (5, 6), which acts on the material to be crushed, may be moved relative to a support body (7) by means of a drive unit (15, 16) and which, together with a second tool blade, forms the variable mouth (17) of the demolition apparatus (1), wherein vibrational movements are superposed at least temporarily on the closing force acting on the tool blades (5, 6), said vibrational movements being triggered at least at one of the tool blades (5, 6) only when the closing force acting between the tool blades has increased to a predetermined, adjustable minimum value.
2. Method according to Claim 1, characterised in that the vibrational movements are respectively interrupted after a predetermined, adjustable time span has passed.
3. Method according to at least one of the preceding claims, characterised in that the generation of vibrational movements is prevented when the tool blades (5, 6) have approached a predetermined end position in the course of the closing movement.
4. Demolition apparatus in the form of demolition claws (1) or shears for implementing the method according to at least one of the preceding claims, with at least one driven tool blade (5, 6) acting on the material to be crushed which is movably held on a support body (7) and, together with a second tool blade, forms the variable mouth (17) of the demolition apparatus (1), with a vibration generator (33), which during operation of the drive unit (15, 16) may be switched on for the at least one movable tool blade and by means of which vibrational movements acting on the material to be crushed (3) may be triggered at the mouth (17), and with a switching unit (27), through the operation of which the vibrational movements of the drive unit (15, 16) may be triggered for at least one tool blade (5 or 6) on this only after a characteristic value representing a dimension for the load application during the demolition process has increased to a predetermined, adjustable minimum value.
5. Demolition apparatus according to Claim 4, characterised in that the longest possible duration of the vibrational movements is adjustable by means of a time function element (28, 41) which enables the vibration generator (33) to be active when the characteristic value increases to the minimum value.
6. Demolition apparatus according to Claims 4 to 5, characterised in that a sequence valve (27) controlled by the operational pressure of the drive unit (15, 16) is provided and has a time function element (28, 41), by means of which the vibration generator (33) may be switched on; and that its energy supply may also be interrupted independently of the position of the sequence valve (27) via the time function element (28, 41).
7. Demolition apparatus according to at least one of Claims 4 to 6, characterised in that at least one driven tool blade (6) has a limit switch (19) allocated to it, by means of which the vibration generator (33) is switched off when the tool blade approaches a predetermined end position during the closing movement.
8. Demolition apparatus according to at least one of Claims 4 to 7, characterised in that the vibrational movements are also triggered by means of at least one percussion device (43) supported on a tool blade (5 or 6).
9. Demolition apparatus according to at least one of Claims 4 to 7, characterised in that the vibrational movements are also triggered by means of at least one imbalance generator (47) supported on a tool blade (5 or 6).

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