JP4685427B2 - Work machine - Google Patents

Description

  According to the present invention, a base is attached to a work machine main body such as a lower traveling body and a work arm such as a boom or a lift arm that can be lifted and lowered at the tip side, and a tip side of the work arm is lifted and lowered by extending and contracting. The present invention relates to a working machine such as a hydraulic excavator, a wheel loader, a lift truck, and the like that are provided with a hydraulic cylinder that is driven by a motor.

  In a working machine that performs construction work such as a hydraulic excavator, a wheel loader, and a lift truck, a work arm that can be attached to the main body of the work machine and lifted and lowered at the tip side, and a tip and arm side of the work arm that is raised and lowered And a hydraulic cylinder for driving as described above. For example, a hydraulic excavator includes a boom and an arm as a working arm for supporting a work tool such as a bucket, and a boom cylinder and an arm cylinder as a hydraulic cylinder for driving the boom and the arm. The boom is tiltably installed so that the base can be pivotally attached to the lower traveling body as the work machine body so that the tip side can be lifted and lowered, and can be tilted by expansion and contraction of the boom cylinder. This hydraulic excavator performs various operations such as an operation of excavating earth and sand with a bucket by driving a work tool such as a working arm of a boom or an arm or a bucket, and an operation of loading excavated earth and sand into a transport vehicle.

  The wheel loader includes a lift arm as a work arm for supporting a bucket as a work tool, and a lift cylinder as a hydraulic cylinder for driving the lift arm. A base is pivotally attached to a vehicle body as a work machine main body so that the tip side can be raised and lowered, and can be raised and lowered by expansion and contraction of a lift cylinder. This wheel loader drives a lift arm and a bucket, and performs operations such as picking up loose materials such as earth and sand with a bucket and loading them into a transport vehicle. The lift truck further includes a lift arm as a work arm for supporting a work tool such as a fork and a hydraulic cylinder for driving the lift arm. It is installed so that it can be pivoted and the tip side can be raised and lowered, and it can be raised and lowered by expansion and contraction of the hydraulic cylinder. This lift truck performs unloading work using a lift arm, a fork or the like.

  In this type of work machine having a hydraulic actuator, for example, a hydraulic pump, an engine for driving the hydraulic pump, a hydraulic oil tank for storing hydraulic oil, and hydraulic oil such as a hydraulic cylinder are supplied to hydraulic actuators such as hydraulic cylinders. Various devices such as a hydraulic hose for discharging to the hydraulic oil tank and a control valve for controlling the pressure oil supplied to the hydraulic actuator are installed in the building as appropriate, and work arms such as booms and lift arms are installed. It is arranged below. When a worker performs maintenance and inspection work on these devices, the work arm is raised to a position where it does not interfere with the work by extending the hydraulic cylinder.

  In that case, it is dangerous to drop the work arm due to damage to the hydraulic piping such as the hydraulic hose or unintentional misoperation of the hydraulic cylinder. In order to prevent this, a stopper separate from the work machine is provided. This stopper can be mounted with one end attached to the tip of the cylinder rod of the hydraulic cylinder and the other end in contact with the tip of the cylinder tube of the hydraulic cylinder when the hydraulic cylinder is extended. It is formed of a strut-like structural member. Then, when carrying out maintenance and inspection work, the operator carries this stopper and attaches it to the extended hydraulic cylinder in the above-mentioned state, thereby restricting the contraction of the hydraulic cylinder, and the work arm is unpredictable. It is intended to prevent falling due to the occurrence of a situation.

  However, since such a stopper needs to be formed of a high-strength structural member and is heavy, an operator carries it and attaches it to the tip of the cylinder rod of the hydraulic cylinder at a high position. It takes a great deal of labor and time to mount the tube while making contact with the distal end surface of the tube, and to remove and remove the mounted stopper. In addition, since it is manufactured separately from the work machine, it may be lost. In order to solve these problems, a device related to a work vehicle with a work implement fall prevention mechanism described in Patent Document 1 has been proposed.

  This Patent Document 1 shows an example in which the idea related to a work vehicle with a work implement fall prevention mechanism is applied to a wheel loader. In the prior art described in this Patent Document 1, a work drop prevention plate is rotatably connected to a pin for pivotally attaching the tip of a cylinder rod of a lift cylinder to a lift arm. An engaging portion that can be engaged with the cylinder rod of the lift cylinder is provided, and a contact surface that can be brought into contact with the tip surface of the cylinder tube of the lift cylinder to restrict the contraction of the lift cylinder is provided. Yes. And, when this work drop prevention plate is rotated to the use position for carrying out maintenance and inspection work, the engaging part of this plate can be engaged with the cylinder rod of the lift cylinder. The plate is configured to be stored by being rotated to a storage position for storing the plate and screwed to the side of the lift arm with a bolt.

  Since the conventional technique described in Patent Document 1 is configured as described above, when performing maintenance or inspection work, after the lift cylinder is extended, the work drop prevention plate in which the worker is in the storage position is provided. When the plate is removed and rotated to the use position, the plate engages with the cylinder rod of the lift cylinder. In this state, when the lift arm descends due to an unexpected situation, the contact surface of the work drop prevention plate contacts the tip surface of the cylinder tube of the lift cylinder to prevent the lift arm from further descending. Further, when the maintenance and inspection work is completed, the worker can store the work drop prevention plate by screwing it to the lift arm with a bolt after rotating the work drop prevention plate to the storage position.

The work-prevention plate used in this conventional technology is usually adopted because the worker only has to turn it to the use or storage position at the start or end of maintenance or inspection work. There is no need to carry a heavy object like the stopper and attach it to a hydraulic cylinder at a high position, or remove it and remove it. . Also, the work drop prevention plate is pivotally attached to the tip of the cylinder rod of the lift cylinder with a pin, so unlike the stopper manufactured separately from the work machine, there is no risk of losing it. .
Japanese Utility Model Publication No. 6-82162 (pages 6-9, Fig. 1-9)

  Although this prior art has these advantages, there is still room for improvement. In other words, the work drop prevention plate as a work arm fall prevention means for preventing the work arm from falling during maintenance and inspection work needs to be formed of a high-strength structural member like the stopper. Although it is heavy, at the end of maintenance and inspection work, the lift arm as the work arm is in a state where the heavy work fall prevention plate is rotated so that the worker lifts it upward and is positioned at the specified position. This work requires a lot of work because it must be screwed in and stored.

  Also, at the start of maintenance and inspection work, the heavy work fall prevention plate stored in this way is rotated so that it is lowered by gravity after the worker removes it from the lift arm, and the engaging portion of this plate is moved. Engage with the cylinder rod of the lift cylinder. At this time, there is a risk that the work fall prevention plate may hit the human body or the operator's hand may be caught between this plate and the cylinder rod. However, it cannot be said that the work arm fall prevention means according to the prior art can be handled safely. Furthermore, after the inspection work is completed, the plate for preventing work drops is placed and stored in the side area of the lift arm, so use other side areas such as attaching other objects to the side of the lift arm. When you are subject to design constraints.

  The present invention was created in order to solve such problems found in the prior art, and the technical problem is that the work arm fall prevention means is provided at the start and end of maintenance and inspection work. It is an object of the present invention to provide a work machine that can be handled more easily and safely and that does not require the fall prevention means to be disposed in the region of the work arm after the inspection work is completed.

In order to achieve the above technical problem, the present invention
The working arm by stretching includes a working arm which can be raised lower the distally attached to the base to the work machine body, and a cylinder tube and slidably fitted interpolated cylinder rod in the cylinder tube and a hydraulic cylinder for driving the at working machine configured as to lower the front end side of the working arm said when the hydraulic cylinder extension increases the distal end of the working arm when contraction of the hydraulic cylinder,
A cover member attached to the distal end portion of the cylinder rod to cover the cylinder rod, comprises a groove having a substantially equal width and height as the cross-sectional shape of the cover member, by inserting the cover member in the groove, the said cylinder having a slider comprising a mounting portion having a substantially semicircular abutment surface fixed to the front surface of the head portion of the sliding portion and the cylinder tube sliding the cover member in the axial direction of the hydraulic cylinder provided with a protective device of the rod is provided with a stopper means capable of stopping the sliding of said cover member so as to regulate the contraction of the hydraulic cylinder during the extension of the hydraulic cylinder,
The stopper means is inserted into a long hole pin hole provided in the cover member, a pin hole provided in the slider, and a long hole pin hole provided in the cover member, and a pin provided in the slider The pin is configured to be fitted into the hole.

  In order to start maintenance and inspection work in the working machine of the present invention provided with such a cylinder rod protection device and stopper means, first, the hydraulic cylinder is extended. Then, while the cover member is guided by the sliding portion of the slider, the cover member slides so as to rise accompanying the tip of the cylinder rod of the hydraulic cylinder, and the tip side of the work arm rises. When the working arm is raised to a position that does not interfere with maintenance and inspection work, the contraction operation of the hydraulic cylinder is restricted by the stopper means. During this time, the cover member with a heavy weight can be slid by the extension force of the hydraulic cylinder, so that no human power is required, and the worker only needs to handle the stopper means, and the work arm fall prevention means Can be handled easily and safely.

  On the other hand, after the maintenance and inspection work is completed, it is not necessary to manually move the heavy cover member as in the prior art, and simply restrict the contraction operation of the hydraulic cylinder by the stopper means. You can cancel it. In this state, when the hydraulic cylinder is expanded and contracted and a desired work is performed on the work machine, the cover member slides in the axial direction of the hydraulic cylinder while being guided by the slider sliding portion as the hydraulic cylinder expands and contracts. Therefore, it is possible to carry out the work with the work machine without any trouble even if the cover member forming the work arm fall prevention means is not housed in a special area such as the side of the work arm as in the prior art. Can do.

  As described above, according to the working machine of the present invention, the work arm drop prevention means can be handled more easily and safely than the conventional technique at the start and end of maintenance and inspection work. After the end, it is not necessary to arrange the fall prevention means in the work arm area. When working with a working machine that extends and lowers the tip of the working arm by extending and retracting the hydraulic cylinder, the axis of the hydraulic cylinder is kept with the cover member covering the cylinder rod accompanying the operation of the tip of the cylinder rod of the hydraulic cylinder. Because the cylinder rod slides in the direction, the peripheral surface of the cylinder rod that needs to be a smooth surface is protected from the outside by the cover member, and the peripheral surface comes into contact with peripheral objects, collision of flying objects such as stepping stones, etc. Can prevent sticking.

  As will be apparent from the following description, the work machine of the present invention is provided with the cylinder rod protection device and the stopper means as described in the above section [Means for Solving the Problems]. The work arm fall prevention means can be handled more easily and safely than conventional technology at the start and end of work, and it is not necessary to place the fall prevention means in the work arm area after the inspection work is completed. It will be over.

  In the working machine of the present invention, the peripheral surface of the cylinder rod, which needs to be a smooth surface, is protected from the outside by a cover member, and the peripheral surface is in contact with peripheral equipment and collision of flying objects such as stepping stones. It is possible to prevent sticking due to the like. Furthermore, the cover member of the protection device for the cylinder rod that constitutes means for preventing the work arm from falling is attached to the tip of the cylinder rod, and the slider of the protection device is fixed at the position on the tip side of the cylinder tube. While the working machine of the present invention exhibits the excellent effects not seen in the conventional technology as described above, there is no fear of losing the work arm fall prevention means, and the same advantages as the conventional technology are maintained. ing.

  Hereinafter, how the present invention is actually embodied will be described with reference to FIGS. 1 to 9 to clarify a desirable mode for carrying out the present invention.

  FIG. 1 is a side view showing an overall image of a lift truck, FIG. 2 is a side view of a lift truck showing an example in which the present invention is applied to the lift truck, and FIG. 3 is a schematic diagram of the lift truck shown in FIG. 4 is an enlarged side view, FIG. 4 is an arrow view of the cover member as viewed from the arrow X direction in FIG. 3, FIG. 5 is an arrow view of the slider as viewed from the arrow Y direction in FIG. 4 is a view similar to FIG. 4 showing a first modification of the cover member of FIG. 4, FIG. 7 is a view similar to FIG. 4 showing a second modification of the cover member of FIG. 4, and FIG. FIG. 9 is a cross-sectional view of the cover member of FIG. 7, and FIG. 9 is a view similar to FIG. 5 showing a slider used for the cover member of FIG.

  The present invention includes a work arm such as a boom or a lift arm that can attach and detach a base portion to a work machine body, a cylinder tube, and a cylinder rod that is slidably inserted into the cylinder tube. It has a hydraulic cylinder such as a boom cylinder or lift cylinder that drives the work arm by extending and contracting, and when the hydraulic cylinder is extended, the tip side of the work arm is raised and when the hydraulic cylinder is contracted, the tip side of the work arm is lowered The present invention can be applied to a work machine that performs construction work such as a hydraulic excavator, a wheel loader, a lift truck, and the like that are configured to perform the above. Here, an example in which the present invention is applied to a lift truck will be described.

  First, an overview of a lift truck to which the present invention is applied will be outlined with reference to FIG.

  In FIG. 1, reference numeral 1 denotes a base for installing the lift arm 2, the cab 13 and the like. The body of a lift truck as a work machine main body capable of traveling on a work site, 1a is a front wheel of the vehicle body 1, 1b Is a rear wheel of the vehicle body 2, a lift arm as a work arm that can be lifted and lowered with the base attached to the vehicle body 1, and 8 is fitted inside the lift arm 2 to be slidable in the axial direction thereof A work tool mounting member for mounting a work tool such as a fork 9 and the like, 9 is a fork having a substantially inverted L-shaped cross section that can be pivotally mounted on the work tool mounting member 8 and can be loaded. A hydraulic cylinder for a fork that is pivotally mounted on the mounting member 8 and drives the fork 9 to rotate, and 11 is a working tool mounting member that drives the work tool mounting member 8 to slide in the axial direction of the lift arm 2. Oil of Cylinder, 12 is a column by a hydraulic jack that supports the vehicle body 1 so as to increase stability when working on the lift truck, 13 is a cab for various operations related to the lift truck, 14 is a hydraulic pump, engine, This is a building cover that incorporates the aforementioned various devices such as a hydraulic oil tank, a hydraulic hose, and a control valve.

  The lift arm 2 is pivotally mounted at the rear end of the vehicle body 1 so as to be swingable. The lift arm 2 is installed beside the cab 13. A lift arm hydraulic cylinder 5 shown in FIGS. By extending and contracting, it can be driven to be raised and lowered. The lift arm 2 is also referred to as a boom. The fork 9 is used, for example, when loading materials at a construction site to perform unloading work, or loading grass that has been cut off at a farm or the like and transporting it upward. A work tool other than the fork 9 can be attached to the work tool mounting member 8. The work tool such as the fork 9 can be rotated by the hydraulic cylinder 10 for fork and the work tool mounting member 8 is driven in the axial direction of the lift arm 2 by the hydraulic cylinder 11 for the work tool mounting member. Can be moved forward and backward.

  In FIG. 1, the state when the lift arm 2 is lowered is indicated by a solid line, and the state when the lift arm 2 is raised is indicated by a two-dot chain line. As can be seen from the figure, when the lift arm 2 is lowered to the state indicated by the solid line, it approaches the building cover 14. Accordingly, when the worker performs maintenance and inspection work on the various devices built in the building cover 14, as described above, the working arm is extended by extending the hydraulic cylinder 5 for the lift arm. It is necessary to raise the lift arm 2 to a position that does not interfere with maintenance and inspection work. The matters described above are general technical contents regarding lift trucks.

  Next, based on FIG. 2 thru | or FIG. 5, the characteristic matter regarding this invention and the matter relevant to this are demonstrated.

  In these drawings, 3 is a cover member attached to the tip of the cylinder rod 52 of the hydraulic cylinder 5 for the lift arm and covers the lower side of the cylinder rod 52, and 4 has a sliding portion 43 for sliding the cover member 3. The slider 5 fixed to the tip of the cylinder tube 51 of the hydraulic cylinder 5 for the lift arm has a cylinder tube 51 and a cylinder rod 52 slidably fitted in the cylinder tube 51, and expands and contracts. The lift arm hydraulic cylinder 6 that drives the lift arm 2 so as to raise and lower the front end side of the lift arm 2 is fixed to the rear portion of the vehicle body 1 and the rear end portion of the lift arm 2 and the lift arm hydraulic cylinder 5 swings. A bracket 6a that can be pivotally attached, a bracket 6a that is fixed to the lift arm 2 and the tip of the cylinder rod 52 is pivotally attached, and 7 Blocks covering member 3 is fixed to the distal end portion of the cylinder rod 52 is attached, 100 is a protective device of the cylinder rod to protect the circumferential surface of the cylinder rod 52 and a cover member 3 and the slider 4.

  The cover member 3 is formed of a long plate-like member having a width wider than the diameter of the cylinder rod 52, and is formed slightly longer than the cylinder rod 52. The cover member 3 is formed with a relatively long elongated pin hole 32 near the rear end thereof, and a bolt insertion hole 31 is formed in the front end portion. The cover member 3 can be attached to the distal end portion of the cylinder rod 52 via the block 7 by inserting the bolt 21 through the bolt insertion hole 31 and screwing it onto the block 7. When the cover member 3 is attached to the tip of the cylinder rod 52 in this way, the cover member 3 moves forward and backward and swings as the cylinder rod 52 protrudes and retracts from the cylinder tube 51 and the hydraulic cylinder 5 swings.

  The cylinder tube 51 is provided with a head portion 51a having a diameter larger than that of the rear portion on the distal end side, and a slider having a diameter smaller than that of the head portion 51a and slightly larger than that of the cylinder rod 52 is attached to the distal end portion. The part 51b is attached. A plurality of screw holes into which bolts 23 to be described later can be screwed are formed on the front side of the head portion 51a so as to correspond to bolt insertion holes 44 to be described later. As shown in FIG. 5, the slider 4 is roughly screwed to the front surface of the head portion 51 a of the cylinder tube 51 by a bolt 23 and a sliding portion 43 through which the cover member 3 is inserted and slid. It is comprised with the attaching part 45 for attaching.

  The sliding portion 43 of the slider 4 forms a lower side of the slider 4 by providing a groove 43 a having a width and height substantially equal to the cross-sectional shape of the cover member 3 through which the cover member 3 can be inserted. . A pin hole 42 for fitting the fixing pin 22 is formed in the top wall of the sliding portion 43 forming the groove 43a. On the other hand, the mounting portion 45 of the slider 4 forms a substantially semicircular contact surface 41 which is in contact with the slider mounting portion 51b of the cylinder tube 51 so that the slider 4 can be mounted, thereby constituting the upper side of the slider 4 is doing. A plurality of bolt insertion holes 44 through which the bolts 23 can be inserted are formed in the mounting portion 45 and arranged in an arc shape. When the slider 4 is fixed to the tip of the cylinder tube 51, the substantially semicircular contact surface 41 of the mounting portion 45 is in contact with the lower half of the slider mounting portion 51b of the cylinder tube 51. The bolts 23 are fixed by being inserted into the plurality of bolt insertion holes 44 of the attachment portion 45 and screwed into the head portion 51 a of the cylinder tube 51.

  After the cover member 3 is inserted into the sliding portion 43 of the slider 4 fixed to the tip of the cylinder tube 51 in this way, the bolt 21 is inserted into the bolt insertion hole 31 of FIG. When the front end portion of the cover member 3 is attached to the tip end portion of the cylinder rod 52, the cover member 3 slides in the axial direction of the hydraulic cylinder 5 while covering the lower part of the cylinder rod 52 when the hydraulic cylinder 5 for the lift arm extends and contracts. It is installed so that it can move. As a result, the cylinder rod protection device 100 is formed by the cover member 3 and the slider 4, and the peripheral surface of the cylinder rod 52 that needs to be a smooth surface is protected from the outside by the cover member 3 so as not to be caught. Is done.

  In the lift truck shown in FIG. 2, the cylinder rod protection device 100 that performs such a function can be used as a work arm fall prevention means for preventing the work arm from dropping during maintenance and inspection work. It is intended to be used heavily. Therefore, in this lift truck, in addition to providing the cylinder rod protection device 100, the sliding of the cover member 3 is stopped so as to restrict the contraction of the hydraulic cylinder 5 when the lift arm hydraulic cylinder 5 is extended. Stopper means is provided. In the example shown here, the stopper means includes an elongated pin hole 32 formed in the cover member 3, a pin hole 42 formed in the slider 4, and a fixing pin 22 that can be removably fitted in the pin hole 42. It consists of.

  When this stopper means is used, the elongated hole pin hole 32 of the cover member 3 is positioned at the position of the pin hole 42 of the slider 4 while the lift arm hydraulic cylinder 5 is extended and the cover member 3 is slid. After the alignment, the fixing pin 22 is fitted into the pin hole 42 of the slider 4 while being inserted into the long hole pin hole 32 of the cover member 3. In this state, the lift arm 2 is raised to a position that does not interfere with maintenance and inspection work. At this time, when the lift arm hydraulic cylinder 5 contracts due to the occurrence of an unexpected situation and the lift arm 2 descends, the cover member 3 slides so as to move backward. Since the front edge portion of the hole-shaped pin hole 32 immediately comes into contact with the fixing pin 22 to stop the sliding of the cover member 3, further lifting of the lift arm 2 can be prevented.

  The effects of the lift truck provided with the cylinder rod protection device 100 and the stopper means as described above will be described.

  When maintenance and inspection work is to be started in the lift truck, the lift arm hydraulic cylinder 5 is first extended. Then, while the cover member 3 is guided by the sliding portion 43 of the slider 4, the cover member 3 slides so as to rise accompanying the tip portion of the cylinder rod 52 of the hydraulic cylinder 5, and the tip side of the lift arm 2 rises. When the lift arm 2 is raised to a position where it does not interfere with maintenance and inspection work, the pin hole 32 of the cover member 3 and the pin hole 42 of the slider 4 are aligned, and the fixing pin 22 of the cover member 3 is moved. It is inserted into the long hole pin hole 32 and fitted into the pin hole 42 of the slider 4, thereby restricting the hydraulic cylinder 5 for the lift arm from contracting due to an unexpected situation. During this time, the cover member 3 having a heavy weight can be slid by the extension force of the hydraulic cylinder 5 and does not require human power. The worker fits the fixing pin 22 into the pin hole 42 of the slider 4. All you have to do is wear it. Therefore, it is possible to handle the cover member 3 that serves as a means for preventing the working arm from falling more easily and safely than the conventional technique.

  On the other hand, after the maintenance and inspection work is completed, it is not necessary to manually move the heavy cover member 3 as in the prior art. The fixing pin 22 is simply moved from the pin hole 42 of the slider 4. It is only necessary to remove the restriction of the contraction operation of the hydraulic cylinder 5 for the lift arm by the fixing pin 22. Therefore, the cover member 3 can be handled more easily and safely than the conventional technique even in the post-processing work after the completion of the maintenance and inspection work. In the state where the restriction of the contraction operation of the hydraulic cylinder 5 is released in this way, when the hydraulic cylinder 5 is expanded and contracted and a desired operation is performed on the lift truck, the cover member 3 moves along with the expansion and contraction of the hydraulic cylinder 5. 4, which slides in the axial direction of the hydraulic cylinder 5 while being guided by the sliding portion 43, the lift truck does not need to be stored in a special area such as the side surface of the lift arm 2 as in the prior art. Can be performed without any problems.

  As described above, according to this lift truck, the work arm fall prevention means can be handled more easily and safely than the conventional technology at the start and end of maintenance and inspection work, and the end of the inspection work. Later, it is not necessary to arrange the fall prevention means on the side surface of the lift arm 2. Therefore, the region of the side surface can be freely used without being restricted by design, such as attaching another object to the side surface of the lift arm 2.

  Further, when the lift arm hydraulic cylinder 5 is expanded and contracted and the work is performed by the lift truck, the cover member 3 covers the cylinder rod 52 in accordance with the operation of the tip of the cylinder rod 52 of the hydraulic cylinder 5 so that the hydraulic pressure is maintained. Since the cylinder 5 slides in the axial direction, the peripheral surface of the cylinder rod 52, which needs to be a smooth surface, is protected from the outside by the cover member 3, and the peripheral surface sticks by contact with peripheral equipment. Can be prevented. Further, when the work machine is a hydraulic excavator or a wheel loader, it can be prevented from being caught due to collision with flying objects such as stepping stones as well as contact with peripheral equipment. Further, the cover member 3 of the cylinder rod protection device 100 that serves as a work arm fall prevention means is attached to the tip of the cylinder rod 52 of the hydraulic cylinder 5, and the slider 4 of the protection device 100 is connected to the cylinder of the hydraulic cylinder 5. Since the lift truck is fixed to the tip of the tube 51, the present lift truck has an excellent effect not seen in the prior art as described above, but there is a risk that the fall prevention means of the work arm may be lost. In addition, it retains the same advantages as the conventional technology.

  Next, various modifications of the cover member 3 shown in FIG. 4 will be described with reference to FIGS.

A cover member 61 shown in FIG. 6 is obtained by changing the relatively long long pin hole 32 into a plurality of long hole pin holes 62 shorter than the long hole pin hole 32 in the cover member 3 of FIG. When a plurality of long hole pin holes 62 are formed in this way, by inserting the fixed pin 22 into any pin hole 62 of the plurality of long hole pin holes 62 and fitting into the pin holes 42 of the slider 4, It is possible to freely select a position where the contraction operation of the lift arm hydraulic cylinder 5 is restricted to prevent the lift arm 2 from descending. Therefore, workers, maintenance, Ru can be selected a position raising the lifting arm 2 during inspection work in the proper position while considering the situation surrounding the site.

  The cover member 3 shown in FIG. 4 is formed of a flat plate-like member so as to cover the lower side of the cylinder rod 52 of the hydraulic cylinder 5, but the cover member 63 shown in FIGS. With the cross-sectional shape shown in FIG. 8 that can surround the cylinder rod 52, not only the lower side of the cylinder rod 52 but also the left and right sides of the cylinder rod 52 can be covered. Accordingly, as shown in FIG. 9, the slider 64 used for the cover member 63 is formed with a groove 65 having a shape that allows the cover member 63 to be inserted and slid. . Since the cover member 63 has the cross-sectional shape as described above, the circumferential surface of the cylinder rod 52 is protected not only from the lower side but also from the outside by the cover member 63 from the outside. Therefore, the cover member 63 is suitable for use in a hydraulic excavator that generates a lot of scattering of earth and sand during work.

Here, two examples of the shape of the cover member are shown. When the cylinder rod 52 of the hydraulic cylinder 5 is covered with the cover member, which region of the cylinder rod 52 is covered is determined by the work machine. What is necessary is just to select suitably according to the work content of. In the example shown here, although attaching the slider 4 to the distal end portion of the cylinder tube 51 of the hydraulic cylinder 5, the slider 4 may be fixed to the position of the distal end side of the cylinder tube 51, it where It doesn't matter whether it is attached and fixed.

It is a side view which shows the whole image of a lift truck. It is a side view of the lift truck which shows the example which applied and applied this invention to the lift truck. It is a side view which expands and shows the principal part of the lift truck of FIG. It is an arrow view of the cover member seen from the arrow X direction of FIG. FIG. 4 is an arrow view of the slider as seen from the direction of arrow Y in FIG. 3. FIG. 5 is a view similar to FIG. 4 showing a first modification of the cover member of FIG. 4. FIG. 5 is a view similar to FIG. 4 showing a second modification of the cover member of FIG. 4. It is a cross-sectional view of the cover member of FIG. It is a figure similar to FIG. 5 which shows the slider used for the cover member of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Lift arm 3 Cover member 4 Slider 5 Hydraulic cylinder for lift arms 7 Block 21, 23 Bolt 22 Fixing pin 31 Bolt insertion hole 32 (Long hole-shaped) pin hole 41 Contact surface 42 Pin hole 43 Sliding part 43a (sliding portion 43) groove 44 bolt insertion hole 45 mounting portion 51 cylinder tube 52 cylinder rod 61 (first modified example) cover member 62 (long hole shaped) pin hole 63 (second modified example) ) Cover member 64 Slider 65 (used for cover member 63) Groove (slider 64) groove

Claims (1)

The working arm by stretching includes a working arm which can be raised lower the distally attached to the base to the work machine body, and a cylinder tube and slidably fitted interpolated cylinder rod in the cylinder tube and a hydraulic cylinder for driving the at working machine configured as to lower the front end side of the working arm said when the hydraulic cylinder extension increases the distal end of the working arm when contraction of the hydraulic cylinder,
A cover member attached to the distal end portion of the cylinder rod to cover the cylinder rod, comprises a groove having a substantially equal width and height as the cross-sectional shape of the cover member, by inserting the cover member in the groove, the said cylinder having a slider comprising a mounting portion having a substantially semicircular abutment surface fixed to the front surface of the head portion of the sliding portion and the cylinder tube sliding the cover member in the axial direction of the hydraulic cylinder provided with a protective device of the rod is provided with a stopper means capable of stopping the sliding of said cover member so as to regulate the contraction of the hydraulic cylinder during the extension of the hydraulic cylinder,
The stopper means is inserted into a long hole pin hole provided in the cover member, a pin hole provided in the slider, and a long hole pin hole provided in the cover member, and a pin provided in the slider A working machine comprising a pin fitted in a hole .

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