DE102005008628B4 - Circular saw with hydraulic drive - Google Patents

Abstract

Circular saw (1) with a rotatable by means of a hydraulic drive circuit Saw blade (1.1), characterized in that the hydraulic drive circuit is provided with a braking device (2) which a Druckstromverbraucher (8), which in a first circuit with a pressure line (6) is connected, wherein in case of braking, the braking device (2) the pressure flow consumer (8) from the pressure line (6) and a throttle (9) effectively connected in series with the pressure flow consumer (8).

Description

The The invention relates to a circular saw according to the generic term of claim 1.

From boaters is required to be turned off from the operating position can be and the saw blade then comes to a standstill within 10 seconds. When driving by an electric motor, this requirement is by attaching a corresponding control element such as an on / off switch or a Emergency stop switch within reach of operating position fulfilled. It For this purpose, a brake motor or a brake switch can be used.

In the prior art is for this purpose, for example DE 34 27 733 A1 a circular saw with discharge brake, in which a braking device is provided for braking the saw blade, which is actuated by an electromagnet and whose brake shoes interact with the saw blade. The brake device is released together with the switching on of the electric motor and activated when switching off the electric motor.

The DE 35 39 841 A1 describes a resistance brake device for armature-mounted electric motors with a field winding or a permanent magnet field generated, in particular for driving hand-held power tools, such as circular saws, drills, planing, milling, grinding machines, with a selectively connected via a switch to a power source power supply lines, either directly or are connected via a field winding with the armature, wherein a two-port resistance braking circuit is provided which can be connected after completion of the engine operation by means of a switching device with its terminals to the power supply lines, and the resistor brake circuit between its terminals with the rising or falling emf of the When braking in the generator mode working motor has increasing or decreasing instantaneous resistance.

These boaters are not for an external drive, usually a PTO drive a tractor, suitable. They each require their own motor on the circular saw.

at Brennholzwippkreissägen with external drive, where the power transmission by means of V-belt is considered an exception to the requirement for disconnectability From the operating position it is possible to switch off the tractor. However, combined firewood and table saws are no exception allowed.

From The company Posch is aware of a system that calls for disconnectability from the operating position in the case of power transmission by means of V-belt met. Two V-belt pulley halves are spring-loaded axially compressed, so that the flanks of the V-belt groove on the V-belt flanks of the V-belt. If the preload is released, the V-belts run through without resistance. The power transmission through the V-belt is interrupted. By divergence The V-belt pulley becomes a segment of the pulley to a Brake disc pressed and the saw blade braked.

This System is relatively expensive to produce. Furthermore, they are in operation regularly wear parts like replace the brake disc and V-belt.

In DE 698 19 952 T2 An attachment for a driven device is described. The apparatus includes a device having an engine and an attachment including a crushing device driven by a hydraulic or electric motor. The disadvantage of this arrangement is that reversible braking to standstill within a short time is thus not possible.

Furthermore, it is off DE 24 46 547 A1 an electrically driven circular saw with a resistance braking device described. Here, when switching off the engine operation of the drive motor is switched to the generator mode and connected to the terminals of the motor, a resistor brake circuit. For hydraulic drives this version is not suitable.

Of the The invention is therefore based on the object, a simply constructed and suitable circular saw and a braking device for to provide a hydraulic drive, which in further embodiments can also be used with a third-party drive.

The The object is achieved by a Circular saw, having the features specified in claim 1, solved.

advantageous Embodiments of the invention are the subject of the respective subclaims.

According to the invention, a circular saw of simple construction has a saw blade which can be rotated by means of a hydraulic drive circuit. Due to the hydraulic drive of the saw blade, apart from the saw blade, which is connected to a hydraulic motor, and a possible hydraulic pressure generator, no moving parts are required sary. The circular saw can also be designed compact without the drive forces must be diverted consuming.

Preferably is the hydraulic drive circuit with a braking device Mistake. As a result, the circular saw on an increased work safety.

A preferred embodiment provides that as a pressure power generator in the drive circuit a Hydraulic pump is arranged, which by means of an electric motor or can be driven by means of a PTO shaft. The electric hydraulic pump allows the use of commercially available electric motors and is thus inexpensive used. Especially in connection with a from the operating position achievable braking device allows driven by PTO Hydraulic pump in the case of combined Brennholzwipp- and Tischkreissägen the Third party drive with reversible braking capability, yet simple Construction of the circular saw.

In an alternative embodiment the drive circuit is connected to a secondary hydraulic system, For example, a hydraulic system of a tractor. This is no separate pressure generator required, one drive for one such also not. Hydraulic pump and associated oil tank, electric motor or PTO can Completely omitted.

Especially on the circular saw according to the invention, but also succeed on any other hydraulically driven machines a reversible deceleration to a standstill within a defined Time with low design and cost in a first embodiment in that, in the case of braking, the braking device is the pressure-flow consumer from the pressure line and a throttle effectively in series with the pressure current consumer switches. In addition to the interruption of Power supply of the drive train is the movement of the machine through the throttle immediately opposed to a resistance, causing them is slowed down.

A advantageous embodiment of the braking device provides, that the pressure flow consumer parallel to the pressure line via a check valve is connected to a low pressure area, wherein the check valve is permeable in the direction of the pressure current consumer. This circuit makes it possible in case of brake hydraulic fluid also from the low pressure range, whereby the braking process resulting heat is better transported and distributed.

advantageously, in case of braking, the braking device provides a second circuit for the pressure line and a separate third circuit in which the pressure power consumers and the throttle are, forth. So it succeeds in a simple way, the first circuit and thus to interrupt the supply of energy and the existing kinetic energy of the pressure electricity consumer over the Reduce throttle.

A second embodiment a braking device provides that in braking the braking device separates the pressure flow consumer from the pressure line and the pressure line connects with a throttle and a pressure-actuated delay device. Also by this embodiment succeeds both on the circular saw according to the invention, but also on any other hydraulically driven machines reversible deceleration to a standstill within a defined time with low Construction and cost. Depending on the mode of action of the delay device are no wearing parts required, for example in the case of an eddy current brake.

advantageously, In this case, in the case of braking, the braking device provides a second circuit for the pressure line, in which the throttle and the delay device lie, and a self-contained third cycle in which the pressure current consumer is, forth. Be easy so the first cycle and thus the power supply interrupted and the delay device activated, reducing the existing kinetic energy of the pressure electricity consumer is reduced.

Preferably is in the embodiments mentioned a directional control valve is provided, which reversibly for separating the first Circulation and establishing the second circuit and the third Circulation serves. The directional valve allows in the form of a single Component reversible, simultaneous disconnection, switching and manufacturing hydraulic circuits with a single mechanical movement that can also be triggered by hand. There are no wearing parts required.

In an advantageous embodiment, the throttle is a pressure relief valve educated. It is a wear-free, cost-effective Component.

A sees particularly preferred embodiment before that the brake case can be triggered by a switch, which is arranged in the region of an operating position. Thereby the safety at work is high and the operated machine is in accordance with the regulations Operating position off can be switched off.

A high level of safety of the hydraulically driven system is achievable by the braking event by proximity detectors such as light barriers, Motion detector or electrical contacts can be triggered. These proximity detectors are preferably arranged in the working area of the installation in order to protect persons located or approaching there.

Conveniently, is the pressure line of the hydraulic drive with a pressure generator or with a secondary Hydraulic system connected. The pressure generator can in turn advantageously powered by an electric or gasoline engine or a PTO become. These parts and a separate oil tank can be omitted if an external Hydraulic system can be connected is, for example, on a tractor.

For certain Applications, for example in vehicles, is an advantageous one embodiment provided in which the throttle is variably adjustable. extreme delay moments are thereby avoidable.

The Invention will be explained below with reference to exemplary embodiments.

To demonstrate:

1 a circular saw in parallel perspective view,

2 . 3 Braking devices with own pressure generation,

4 . 5 Braking devices with external pressure power generation and

6 a braking device with a separate deceleration device.

In the 1 illustrated circular saw 1 is hydraulically driven. The saw blade 1.1 is about the wave 1.2 and a dog clutch 1.3 mechanically with a hydraulic motor 1.4 connected, which acts within the hydraulic drive as Druckstromverbraucher. The hydraulic motor 1.4 is via hydraulic lines 1.5 . 1.6 with a pressure relief valve 1.7 connected, which in the case shown directly to a 4/2 way valve 1.8 connected. This is via a hydraulic line 1.9 with a pressure generator and a hydraulic line 1.10 connected to a not shown oil tank. The combination of pressure relief valve 1.7 and directional valve 1.8 serves as a braking device 2 for the circular saw 1 , During operation, the pressure generator drives the hydraulic motor 1.4 and with it the saw blade 1.1 at. Will the directional valve 1.8 actuated, the energy supply to the hydraulic motor 1.4 interrupted and a closed hydraulic circuit between the hydraulic motor 1.4 and pressure relief valve 1.7 created so that they are connected in series. This will be the hydraulic motor 1.4 including the saw blade 1.1 braked within 10 seconds. The pressure generator is not shown here, it is a hydraulic pump, which is driven by an electric motor.

2 shows a detailed illustration of a circuit diagram of a braking device 2 , It is functionally consistent with the exception of the pressure generator 1 described braking device 2 match. The braking device 2 , which is mounted on a machine with a rotating tool, has a hydraulic pump as a pressure generator 3 on that by the PTO 4 a tractor is driven. The pressure generator 3 is on the one hand with an oil container 5 and on the other hand via the pressure line 6 with a first connection 7.1 a 4/2 way valve 7 connected. A second connection 7.2 of the directional valve 7 is as a return to the oil tank 6 connected. The 4/2 way valve 7 is mounted as an actuator within reach of the operating position. The braking device 2 thus fulfills the function of a brake motor.

In the first position of the directional control valve 7 is a third connection 7.3 of the directional valve 6 is with the input of a pressure electricity consumer 8th connected in the form of a hydraulic motor and a fourth connection 7.3 is at the output of the pressure electricity consumer 8th connected. Pressure power generator 3 and Druckstromverbraucher 8th form a first cycle. Parallel to the pressure current consumer 8th is a pressure relief valve as a throttle 9 connected. Is the directional valve 7 as shown in its second position, so is its first connection 7.1 directly to the second port 7.2 connected so that the pressure generator 3 in a separate second circuit with the oil tank 5 lies. The first cycle is interrupted. The in itself parallel circuit of the pressure electricity consumer 8th with the throttle 9 effectively becomes a series connection of the two elements by the interruption of the first circuit, which constitutes its own third circuit. The throttle 9 acts as a resistance.

In the first position of the 4/2 way valve 7 the hydraulic oil flows through the pressure flow consumer 8th and drives the tool. Will the 4/2 way valve 7 brought to the second position, the idle position, by an operation to the operation, the tool by the resistance, the pressure relief valve as a series-connected throttle 9 generated, braked. This happens with appropriate preload of the pressure relief valve within 10 seconds.

3 shows the circuit of an alternative braking device 2 which is preferably usable, To avoid waste heat problems by a small amount of oil in the closed third hydraulic circuit, which can occur with high heat generation during the braking process. The input of the pressure electricity consumer 8th is parallel to via the directional control valve 7 extending pressure line 6 via a check valve 10 directly with the oil container 5 , So the low pressure area of the first circuit connected. The check valve 10 is in the direction of the pressure electricity consumer 8th permeable. The throttle 9 is here from the outset in series with the pressure current consumer 8th switched and at its exit with the oil tank 5 connected, but is in the first position of the directional control valve 7 as well as the check valve 10 effectively not flowed through. Will the 4/2 way valve 7 brought by an operating action in the illustrated second position, the first circuit is interrupted and due to the inertia of the tool, the check valve 10 and the throttle 9 flows through. They form with the pressure current consumer 8th a separate, third circuit. The tool is characterized by the resistance of the pressure relief valve as a series-connected throttle 9 braked.

In the 4 illustrated braking device 2 Functionally corresponds essentially to the in 2 shown. However, the drive in this case is not done by the PTO of the tractor, but by its on-board hydraulic system. This allows the pressure generator 3 and the oil container 5 omitted. The 4/2 way valve 7 is in the illustrated switching state in the second position.

5 shows the circuit of an alternative braking device 2 , which is preferably used to avoid waste heat problems by a small amount of oil in the closed third hydraulic circuit, which can occur with high heat generation during the deceleration process. It essentially corresponds to the circuit in 3 , but the drive is analogous to the example of 4 not by the PTO of the tractor, but by its on-board hydraulic system. This allows the pressure generator 3 and the oil container 5 omitted. The throttle 9 is on its output side and the check valve 10 connected directly to a low pressure line of the secondary hydraulic system of the tractor on its inlet side. Also in this example is the 4/2 way valve 7 in the illustrated switching state in the second position.

In 6 is an alternative embodiment of a braking device 2 shown. The braking device 2 , which is attached to a circular saw, is via the first and the second connection 7.1 . 7.2 a 6/2 way valve 7 connected to a secondary hydraulic system of a tractor. The directional valve 7 is mounted as an actuator within reach of the operating position. The braking device 2 thus fulfills the function of a brake motor.

In the first position of the directional control valve 7 is a third connection 7.3 of the directional valve 6 is with the input of a pressure electricity consumer 8th connected in the form of a hydraulic motor and a fourth connection 7.3 to the output of the pressure electricity consumer 8th connected. Is the directional valve 7 in its second position as shown, so is its first connection 7.1 with the fifth connection 7.5 and his second connection 7.2 with the sixth connection 7.6 connected so that the pressure line 6 a separate second circuit with the delay device 11 and the throttle 9 forms. The first cycle is interrupted. The third and the fourth connection 7.3 . 7.4 the directional valve 7 are directly connected to each other, so that the pressure current consumer 8th short circuited in a third circuit.

In the first position of the 4/2 way valve 7 the hydraulic oil flows through the pressure flow consumer 8th and drives the saw blade of the circular saw. If the working machine is to be braked, the directional control valve 7 actuated. As a result, the power supply to the saw blade is interrupted and to the delay device 11 redirected in the form of a disc brake. The brake pad is on the friction surface 12 the shaft of the saw blade and delays its movement to a stop. Instead of a disc brake any mechanical or electrical deceleration devices can be used, for example a drum brake or an eddy current brake, possibly corresponding converter are required, so that the delay device responds to pressure actuation.

A braking device according to the invention 2 , In particular, in one of the embodiments shown by way of example, can be used with any machine with hydraulic drive. In extended embodiments, the invention can also be used for hydraulic drives, in which the drive direction, in particular the direction of rotation is reversible. Preferably, in the case of braking, the machine is decelerated independently of the current direction of rotation.

For some applications, it is advantageous if the braking device 2 is controllable in terms of the strength of the deceleration, such as for hydraulic vehicle drives. This can be done, for example, by a variably adjustable throttle 9 be achieved. The degree of deceleration may then be controlled, inter alia, by means of a throttle connected to the throttle or a control lever.

In particular, in stationary systems with hydraulic drive high security for operating personnel can be achieved by the braking device 2 can be triggered by proximity detectors. The braking event can be initiated, for example, by photocells or electrical contacts on doors, when people get into the vicinity of critical areas of the system. Also, capacitive proximity detectors that identify a touch of a surface of the equipment or a machine and then trigger the braking event are conceivable.

A hydraulic drive with a braking device according to the invention 2 can also be used to set a large flywheel with a small drive unit in motion, such as a flywheel. The energy stored in this way can be used to allow short term peak loads on the work machine.

1

circular saw

1.1

sawblade

1.2

wave

1.3

claw clutch

1.4

hydraulic motor

1.5 1.6

hydraulic lines

1.7

Pressure relief valve

1.8

way valve

1.9 1.10

hydraulic lines

2

braking means

3

Pressure power generator

4

PTO

5

oilcontainer

6

pressure line

7

way valve

7.1 7.2, 7.3, 7.4, 7.5, 7.6

connections

8th

Pressure electricity consumers

9

throttle

10

check valve

11

delay means

Claims (13)

Circular saw ( 1 ) with a rotatable by means of a hydraulic drive circuit saw blade ( 1.1 ), characterized in that the hydraulic drive circuit with a braking device ( 2 ), which is a pressure current consumer ( 8th ), which in a first circuit with a pressure line ( 6 ), wherein in case of braking the braking device ( 2 ) the pressure current consumer ( 8th ) from the pressure line ( 6 ) and a throttle ( 9 ) effectively in series with the compressed-flow consumer ( 8th ) switches. Circular saw ( 1 ) according to claim 1, characterized in that as Druckstromzeuger ( 3 ) In the drive circuit, a hydraulic pump is arranged, which is drivable by means of an electric motor or by means of a PTO shaft. Circular saw ( 1 ) according to claim 1 or 2, characterized in that the drive circuit is connected to a secondary hydraulic system. Circular saw ( 1 ) according to one of the preceding claims, characterized in that the pressure current consumer ( 8th ) parallel to the pressure line ( 6 ) via a check valve ( 10 ) is connected to a low-pressure region, wherein the check valve ( 10 ) in the direction of the pressure electricity consumer ( 8th ) is permeable. Circular saw ( 1 ) according to one of the preceding claims, characterized in that in the case of braking, the braking device ( 2 ) a second circuit for the pressure line ( 6 ) and a separate third circuit in which the pressure current consumer ( 8th ) and the throttle ( 9 ), manufactures. Circular saw ( 1 ) according to one of the preceding claims, characterized in that in the case of braking, the braking device ( 2 ) the pressure current consumer ( 8th ) separates from the pressure line and the pressure line with a throttle ( 8th ) and a pressure-actuated retarding device ( 11 ) connects. Circular saw ( 1 ) according to claim 6, characterized in that in the case of braking, the braking device ( 2 ) a second circuit for the pressure line ( 6 ), in which the throttle ( 9 ) and the delay device ( 11 ), and a self-contained third circuit in which the pressure current consumer ( 8th ), manufactures. Circular saw ( 1 ) according to claim 5 or 7, characterized by a directional control valve ( 7 ) which reversibly serves to disconnect the first circuit and establish the second circuit and the third circuit. Circular saw ( 1 ) according to one of the preceding claims, characterized in that the throttle ( 9 ) is designed as a pressure relief valve. Circular saw ( 1 ) according to one of the preceding claims, characterized in that the brake case can be triggered by a switch which is arranged in the region of an operating position. Circular saw ( 1 ) according to one of the preceding claims, characterized in that the braking event can be triggered by proximity detectors. Circular saw ( 1 ) according to one of the preceding claims, characterized in that the pressure line ( 6 ) with a pressure generator ( 3 ) or connected to a secondary hydraulic system. Circular saw according to one of the preceding claims, characterized in that the throttle ( 9 ) is variably adjustable.