EP0859089B1 - Device for locking or unlocking a tool on a tool holding frame of a compact loader - Google Patents

Abstract

A skid loader includes forwardly projecting power arms. A carrier frame is hingedly mounted to the power arms by pivot pins and is adapted to support a working implement. The working implement is connected to the carrier frame by locking pins movably disposed on the carrier frame. The locking pins are actuated by a hydraulic device which is supplied with hydraulic fluid by a fluid passage, a portion of which passes through a pivot pin.

Description

Field of the Invention

The invention relates to a compact loader with two hydraulically lifting and lowerable lifting arms, at the front ends for receiving a tool by means of swivel bolts a tool holder frame is articulated, the means for holding the tool used as well Has locking bolt for locking or unlocking. Such a skid steer is e.g. known from US-A-3,269,570 Skid steer loaders are small wheel loaders that are located in the front area at the end of the Lift arms an essentially vertical tool holder frame have, which is pivotable about horizontal pivot pin to this articulated, can be pivoted using a hydraulic cylinder can. Various tools, such as., Can be attached to the mounting frame Gripping tongs, pallet or pitchfork, gravel shovel, etc., attached and with the help of locking bolts in aligned holes of the tool holder frame and the corresponding extension of the tool are used, locked.

Technological background

The lifting arms, which can be raised and lowered hydraulically, are from the rear Area along the side of the driver's cab, which entails considerable dangers for the driver, the ones to be cut Force safety precautions: The driver's cab is mostly covered by a wire mesh on the side, a seat switch and other devices ensure that the skid steer including hydraulics and lifting equipment is shut down if the driver rises from his driver's seat. Because the locking bolts must be set and released by hand, the driver must Change or pick up a tool the skid steer leave, put the locking bolts and back onto the skid steer the seat switch sets the hydraulics quiet. This activity is therefore time consuming and is due to the necessary descent and ascent also associated with dangers. aim the invention is therefore to develop the generic device so that a quick and safe setting down, changing or Picking up the tool is possible.

Brief description of the invention

The locking bolts are by means of a pressure cylinder Hydraulic fluid branched on-board hydraulics can be actuated. With mechanical coupled locking bolt is enough for a pressure cylinder a coupled group; is missing the mechanical coupling, is for everyone Locking bolt provided a pressure cylinder. The hydraulic cylinder (s) the hydraulic fluid is drilled through holes the pivot pin that links the tool holder frame to the lifting arms fed; this allows permanently installed connections outdoors; Swiveling movements can occur within the tool holder frame be compensated via hose connectors; are advantageous here rotary connections. As a result, the rough operation is used Skid steer loader taken into account: those for the connection of the pressure cylinder (s) necessary hydraulic connection lines can not to be damaged; an impairment of the driver's view not applicable. Due to the operability of the locking bolt from Driver seat of the skid steer loader does not leave the Driver's seat when picking up, putting down or changing a tool, so the seat switch doesn't fire and the hydraulics is not switched off. Is related to the tool holder frame positioned on the tool to be picked up and it has the tool holder frame caught, can be locked immediately.

Brief description of the figures

Figure 1

shows the front area in a schematic side view a skid steer loader (not shown), its lifting arms with a tool holder frame are provided, to which a (shown broken off) Tool attached by means of an extension piece and by means of a hydraulically operated device to lock and unlock the tool with Locking bolt is secured;

Figures 2

show the tool holder frame with a simple pivot pin provided with a through hole, attached to one of the lifting arms of the lifting device,
Figure 2a shows a conical pivot pin with a straight hydraulic passage, on both sides with connections and Figure 2b show a cylindrical pivot pin with pressure chamber and hydraulic rotary connection;

Figure 3

shows the tool holder frame with continuous Swivel pin, attached to the lifting arms of the lifting device, the hydraulics facing each other Blind holes and radial holes one double rotary connection is fed;

Figures 4

show details of the power transmission device with a V-shaped yoke and the resetting effect of the compression spring
4a: V-shaped yoke,
4b: U-shaped yoke;

Figure 5

shows a detail of the power transmission device with rocker / lever and resetting Compression spring;

Figure 6

shows a detail of the power transmission device with gear / rack drive and with Compression spring to reset;

Figure 7

finally shows a schematic circuit diagram of the hydraulics (without the general on-board hydraulics).

Description of advantageous embodiments

Fig. 1 shows schematically a on the front area of a (not shown) Compact loader arranged lifting device 10 with two hydraulically lifting and lowering lifting arms 11 and 12, of which Fig. 1st shows the right lifting arm 12 in the direction of travel with details; of the left in the direction of travel has broken out. At the ends of the two Lifting arms 11 and 12 are provided with a tool holding frame 15, the one with a horizontally arranged transverse to the direction of travel Swivel pin 18 is articulated to the lifting arms 11 and 12. The tool holder frame 15 is by means of a (only indicated) Hydraulic cylinder 13, with its piston rod 14 a crossbar 17 of the tool holder frame 15 engages to the Swivel pin 18 swiveling so that it is both in the receiving or Settling position can also be brought into the working position.

The tool holder frame 15 has a wedge shape in its upper region trained receptacles 32 for the tool 16 that with an extension piece 30, which the wedge-shaped receptacles 32 of the tool holder frame 15 engages with its holder hook 31, provided is. On its underside is the extension piece 30 with oblique struts 33 provided, which are also inclined against the Place lower edges 35 of the tool holder frame 15. Tool holder frame 15 and extension 30 are with the help of at least two arranged laterally on the tool holder frame Locking bolt 34 locked or unlocked. To do this they swore Holes 36 in the oblique struts 33 with the corresponding holes in the area of the lower edges 35 of the tool holder frame 15, in which the locking bolts 34 are guided, which at aligned in pairs in the holes 36 of the oblique struts be so that the locking lug 34.1 in this aligned hole 36 can intervene.

For this purpose, the locking bolt 34 via pressure cylinder 40, the via the hydraulic connecting lines connected to the pivot bolts 18 55 and for actuating the locking bolts 34 suitable control switches 58 in the driver's cabin with the on-board hydraulics (see Fig. 7) are connected, operable. The locking bolts 34 (see FIG. 1) for reasons of space near the front area of the tool holder frame 15 arranged; they are therefore using a Force deflection device 38 out of the locking position moved into the unlocked position and vice versa.

The pivot pin 18 is on one side through a bore 20 in one the lifting arms (here lifting arm 11 - the same applies to lifting arm 12) and one further hole in the side wall of the tool holder frame 15 guided; the end of the tool holder frame 15 assigned Swivel pin is conical (Fig. 2a) and corresponding in the conically shaped bore 22 in the tool holder frame 15 lockable. An outer, with (indicated) screws 19.1 fixed locking plate 19 engages over the reduced diameter lifting arm end of the pivot pin 18 and secures its position. The receiving side assigned to the tool holding frame 15 End of the pivot pin 18 emerges from this. The pivot pin 18 is provided with a through axial bore 52 in the lifting arm side End of a screw connection 18.1 for the hydraulics forms. The end on the receiving frame side has an output 18.2 for a hydraulic coupling.

In another embodiment, the pivot pin 18 is cylindrical Insert body formed (Fig. 2b). One with screws 19.1 fixed plate 19 holds it in position. The inner end of the Swivel pin 18 is rotatably mounted in a bushing 25 and by means of a seal 25.1 sealed against the escape of grease; this inner end is further with a hydraulic fitting 18.2 provided to which a (not shown) hose is connected, via which the hydraulic fluid to the pressure cylinder 40 is forwarded.

Becomes a continuous one - for example with relatively narrow skid steer loaders Provided pivot shaft 50, the ends of which form the pivot bolts 18 through the bores 20 and 21 of the lifting arms 11 and 12 as well of the side walls of the tool holder frame 30 and - because the through cylindrical bolt holes - on both sides with the the reduced-diameter ends of the pivot pins on the lifting arm side 18 overlapping and fixed with (indicated) screws 19.1 Locking plates 19 are fixed. With these pivot bolts 18th the tool holder frame is articulated on the lifting arms 11 and 12.

The hydraulic supply is analogous: if the pressure cylinder 40 is single-acting, an axial bore 52 is sufficient; however it is double acting, a pair of opposing axial bores 52 provided, it being understood that the Hydraulic output from the pivot shaft 50 set up accordingly is. In the simplest case, the output connections are 18.2 directly at the mouths of the radial bores 63 on the Shell of the pivot shaft 50 placed. A rotatable one is advantageous Removal sleeve 60, the continuous pivot shaft 50 in the area which covers radial bores 53 opening into the grooves 53.1, and which decouples the pivoting movement. This Removal sleeve 60 can correspond to the annular grooves 53.1 of the pivot shaft 50 Have annular grooves 61 which with radial bores 62 the hydraulic outlet screw connections placed on the outer surface of the removal sleeve 60 18.2 are connected. Inner ring seals 64 ensure that the grooves 53.1 / 61 both against each other as well as sealed from the outside. On both sides Arranged locking disks 65 secure the position of the removal sleeve 60.

Because of the limited space in the front area of a skid steer loader with a tool holder frame articulated to the lifting arms 11 and 12 30, it is advantageous to the axes of movement of the locking bolt 34 of piston rod 40.1 of the pressure cylinder 40 parallel to each other to offset what is an independent of the impression cylinders 40 Placing the locking bolts 34 near the front of the Tool holder frame 30 allowed. For power transmission from Printing cylinder 40 on the locking bolt 34 becomes advantageous a force deflection device 38 is provided.

A mechanical linkage in the form of a V-shaped yoke is used (Fig. 4), a U-shaped yoke (Fig. 5) or a seesaw with one Lever used (Fig. 6 shows only a one-armed lever, Two-armed levers are to be arranged accordingly - without restriction thereon). The locking device 38 with locking bolts 34 has a fixed to the tool holder frame 15 and supported, hydraulically operated (initially as single-acting assumed) pressure cylinder 40 on the hydraulic connecting lines 56 and 55 connected to the on-board hydraulics of the skid steer loader is. Around the locking bolt 34 in the immediate vicinity of the front to be able to arrange on the tool holder frame 15 is the Axis of the pressure cylinder 40 parallel to that of the locking bolt 34 offset, which is actuated via a power transmission device 38 becomes.

Both the hydraulic lines 56 supplying the pressure cylinders 40 are to synchronize the movement of the locking bolts 34 from a hydraulic distributor connected downstream of the hydraulic outlet 18.2 57 derived. With single-acting pressure cylinders the unlocking movement is controlled by pressure and the locking movement from a tensioned during the locking movement Return spring causes, this spring also arranged in the pressure cylinder can be.

In one embodiment, the power transmission device 38 is transfer the movement of the pressure cylinder 40 to a V-shaped yoke, to which the piston rod 40.1 of the pressure cylinder 40 is connected is. One leg 41 of the yoke goes into the locking bolt 34 over, during which other leg 42 one to Locking bolt 34 parallel guide rod 48 has to avoid edges or jamming in a guide 49 is performed. In another embodiment, the yoke is U-shaped. The apex of the U-bend 43 stands with the Piston rod 40.1 in connection and transmits its movement the locking bolt 34 and the guide rod 48.

In a further embodiment of the power transmission device 38, the movement of the pressure cylinder 40 is transferred to a rocker 45: Here the piston rod 40.1 acts on the short lever arm 46 of a lever (shown with one arm), the long lever arm 47 cooperates with the locking bolt 34. Because of the pivot point the lever pivoting movement is the locking bolt 34 to the lever via the sliding block in slot 47.1 articulated, which takes into account the pivoting movement. In both Cases determines the ratio of the two lever arms 46 and 47 the translation of force and displacement: a short-stroke cylinder requires a short lever arm 46 while the locking pin 34 on the long lever arm 47 the longer way to unlock is possible, the higher force can be applied by hydraulic cylinders. For the prevention of annoying and therefore undesirable clamps when the locking bolt moves, the guide 49 Concern: the guide rod 48 guided in it has one to the axis of the Locking bolt 34 parallel axis. This parallelism is for Trouble-free working is essential. It doesn't come up the lateral offset, even without a lateral offset Guide - as shown in Fig. 5, 6 - prevent jamming.

Another way of power transmission is through a toothed gear given; the impression cylinder acts in the selected representation 40 on piston rod 40.1 and coupling plate 40.2 on Gear 44, the coupling plate 40.2 eccentrically to the gear 44 is articulated. The gear 44 in turn acts as Rack-trained rack extension 34.2 of the locking bolt 34 together. If the (shown retracted) When the pressure cylinder is pressurized, the piston rod moves 40.1 and with it the coupling strap 40.2 and twisted it Gear 44 counterclockwise; this will be the rack extension 34.1 of the locking bolt and thus the locking bolt 34 brought itself into the locking position. The Unlocking takes place in reverse. With such gear translations can adapt path and strength to local conditions with the axes of the impression cylinder 40 and the locking bolt 34 can also be at an angle to each other. Here it seems natural, instead of an intermediate one Gear also provide a chain of several gears. Also here a guide 49 avoiding jamming is provided, in FIG the extension of the locking bolt to avoid jamming is led.

The force deflection device with a force accumulator is advantageous provided, which is tensioned when locking, and which in the event of failure the hydraulic lock bolt in the locked position transferred or detained. So an unintentional loosening of the prevented tool in the event of hydraulic failure and the Operational safety increased; such an energy store is, for example a spring 37. To unlock the pressure cylinder 40 with Pressure is applied, piston rod 40.1 is retracted, it lifts the yoke with its leg 42 or with the U-bend 43 and thus the locking bolt 34 from the hole 36 in the extension 30 of the tool 16 is released. When lifting the Piston rod 40.1 becomes, for example, one inside the pressure cylinder 40 arranged spring tensioned so that one for locking of the tool over the locking bolt 34 necessary force even in the event of a hydraulic failure or pressure shutdown on the pressure cylinder is available. The pressure cylinder 40 is a double-acting hydraulic cylinder formed, the piston of the pressure cylinder of hydraulic fluid is applied to both sides. In this Fall can be both unlocked by pulling the locking bolt 34 as described above, as well as locking Set the locking bolt 34 hydraulically.

To secure the locking bolt 34 in the event of pressure or hydraulic failure to bring or hold in its locking position springs 37 which are advantageously arranged externally and can thus be monitored are provided, supported on one side with an abutment 37.1, to a movable part of the force deflection device 38 Act. In Fig. 4a, the spring 37 is a compression spring that when unlocking is tensioned, and the relaxing when the pressure drops the yoke with the locking bolt 34 in the locking position presses. In Fig. 4b, the spring 37 is designed as a tension spring engages the arch 43 of the yoke and is tensioned when unlocking. In the event of pressure loss, this spring 37 shows the yoke with locking bolts 34 in the locked position.

Figures 5 and 6 show with the extension 48 of the locking bolt 34 co-operating springs 37: this is in FIG. 5 Spring 37 designed as a tension spring and with its fixed end on the Guide 49 supported while the free end with the extension 48 connected, the movement of which is taken along. Here is this Spring 37 visibly stretched and unlocked when unlocked. In the Figure 6, the spring 37 is designed as a compression spring and with her fixed end supported on a frame-fixed abutment 37.1, while their free end from the head of the extension 48 of the locking bolt 34 is taken away. The spring 37 can be seen here compressed when unlocking and so tense. The tense Spring 37 pulls the guide rod in the event of hydraulic or pressure failure 48 and with it the locking bolt 34 in the locking position.

FIG. 7 finally shows a circuit diagram for the on-board hydraulics with connected pressure cylinder 40 for unlocking or locking the tool using the locking bolt 34. Hydraulic fluid is stored in a memory by the hydraulic pump 59 of the on-board hydraulics 59.1 funded over several exits (only one is shown here) disposes. The hydraulic cylinders 40 for unlocking and locking of a tool are controlled here with the 4/2 control valve 58. The control valve 58 supplies the connecting line 55, via the hydraulic fluid under pressure through the axial bore 52 in the pivot pin 18 and the hydraulic connection line 56 and the hydraulic distributors 57, which split into two branches, the pressure cylinders 40 is supplied. The pistons are moved and the piston rods 40.1 (according to Fig. 1) retracted or extended. Pressure relief by switching valve 58, the direction of movement is reversed (if necessary via internal springs) and leaves the piston in the starting position go back.

Claims (14)

1. Compact loader with two raisable and lowerable lifting arms (11, 12), for the actuation of which an onboard hydraulic system with pressure generator, expansion tank and working cylinder (13) is provided, to the front ends of which arms a tool-receiving frame (15) for receiving a tool is linked by means of swivel pins, said frame having means for holding the tool used (16) and locking pins (34) for locking and unlocking the latter, characterised in that each of the locking pins (34) is adapted to be actuated with the aid of a pressure cylinder (40), to which the hydraulic fluid tapped from the onboard hydraulic system is adapted to be supplied via an axial bore (52) in at least one of the swivel pins (18) with which the tool-receiving frame (15) is linked to the lifting arms (11, 12) of the compact loader.
2. Compact loader as claimed in Claim 1, characterised in that the movement axis of the locking pin (34) and that of the piston rod (40.1) of the pressure cylinder (40) which actuates the locking pin (34) are arranged parallel and offset in relation to each other, with a power deflection device being provided for the power transmission from the piston rod (40.1) of the pressure cylinder (40) to the locking pin (34).
3. Compact loader as claimed in Claim 2, characterised in that the power deflection device is formed by a yoke having at least two arms (41, 42), the one arm (41) of which is firmly joined to the locking pin (34) and the piston rod (40.1) of the pressure cylinder (40), and the other arm (42) of which is guided in a guide (50) such that it can longitudinally move parallel to the direction of movement of the locking pin (34).
4. Compact loader as claimed in Claim 2, characterised in that the power deflection device is formed by a rocker with a lever (45), to whose one lever arm (46) the piston rod (40.1) of the pressure cylinder (40) is linked and to whose other lever arm (47) the locking pin (34) is linked.
5. Compact loader as claimed in Claim 2, characterised in that the power deflection device is formed by a gear mechanism in which the free end of the piston rod (40.1) of the pressure cylinder (40), having the form of a rack, co-operates with a gear wheel, and by the locking pin (34), the actuating end of which, having the form of a rack, meshes with the gear wheel.
6. Compact loader as claimed in Claim 1, characterised in that the tool-receiving frame (15) is linked at both sides to the corresponding lifting arm (11, 12) by one swivel pin (18) in each case.
7. Compact loader as claimed in Claim 6, characterised in that at least one of the swivel pins (18) is provided with the axial bore (52), to whose inlet the hydraulic supply is adapted to be connected via a hydraulic connection (18.1) and to whose outlet the pressure cylinder (40), designed as a single-acting hydraulic cylinder, is adapted to be connected via a hydraulic outlet union (18.2).
8. Compact loader as claimed in Claim 6, characterised in that both the swivel pins (18) have axial bores (52), to whose inlets the hydraulic supply and to whose outlets the pressure cylinder (40), designed as a double-acting hydraulic cylinder, are adapted to be connected.
9. Compact loader as claimed in Claim 1, characterised in that the tool-receiving frame (15) is linked at both sides to the corresponding lifting arm (11, 12) by means of a continuous swivel shaft having the form of swivel pins (18) at both ends.
10. Compact loader as claimed in Claim 9, characterised in that one of the swivel pins (18) on one side of the swivel shaft is provided with the axial bore (52) having the form of a blind bore, which features in its central region a radial bore (53), covered with a hydraulic outlet union (18.2), to which the pressure cylinder (40), designed as a unilaterally acting hydraulic cylinder, is adapted to be connected.
11. Compact loader as claimed in Claim 9, characterised in that both the swivel pins (18) on each side of the swivel shaft are each provided with an axial bore (52) having the form of a blind bore, each of which features in its central region a radial bore (53), covered with a hydraulic outlet union (18.2), to which the pressure cylinder (40), designed as a bilaterally acting pressure cylinder, is adapted to be connected.
12. Compact loader as claimed in Claim 10 or 11, characterised in that a tapping sleeve (60) is provided, which surrounds the swivel shaft and is designed as a pivoting connection, which sleeve is provided with the hydraulic outlet union/s, with annular grooves (53.1, 61) on the swivel shaft and/or the inside of the tapping sleeves (60) are joined via radial bores (53) with the respective axial bore (52) and via radial bores (62) with the tapping sleeves (60).
13. Compact loader as claimed in any one of Claims 1 to 12, characterised in that the locking pin (34) is provided with an energy storing device which in the event of failure of the hydraulic system pushes the locking pin (34) into the locked position.
14. Compact loader as claimed in Claim 13, characterised in that the energy storing device is a spring (37), preferably a pressure spring, which acts on the locking pin (34) and abuts against the tool-receiving frame (15).

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