Double lock mechanism and working tool

Abstract

To provide a double lock mechanism capable of simultaneously locking a normal lock and a double lock by a single action at the time of locking, and a working tool provided with the same.SOLUTION: A double lock mechanism 80 and a working tool 100 provided with the same are configured so that, when bringing a leg portion 12 into a locked state, by only releasing a first lock member 30 held in an unlocked position by a user, the first lock member 30 automatically rotates by a restoring force of a first elastic member 34 to lock the leg portion 12, and a second lock member 40 automatically slidably moves by an elastic force of a second elastic member 44 to lock the first lock member 30. That is, only a single action at the time of locking provides automatic double lock by the first lock member 30 and the second lock member 40. This allows the user to always use the working tool 100 in a safe state in which the double lock is established without forgetting the double lock.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a double locking mechanism for an extension mechanism provided on the legs of work tools such as stepladders, workbenches, ladders, truck steps, sorting tables, and mobile racks, and to a work tool equipped with the same. [Background technology]

[0002] Ladders, stepladders, platforms, high-altitude work platforms, scaffolding, truck climbing steps for climbing up to the truck bed, etc. are commercially available as work tools having ladder members used for working at high places or moving to high places. Some work tools having such ladder members have a telescopic mechanism that allows the legs located at the bottom of the ladder members to slide up and down. When there is a step or the like on the installation surface, for example, the work tools having such a telescopic mechanism can be used in a stable state where the treads of the ladder members are approximately horizontal by sliding and adjusting the position of each leg to match the step.

[0003] Other working tools with telescopic legs include sorting tables, work tables, mobile racks with wheels, and towing dollies. With these working tools, the position of the platform can be adjusted to a height that is easy to work with by sliding the legs to adjust the position. Furthermore, with working tools with wheels, the legs can be retracted to allow the wheels to touch the ground during movement, and the legs can be extended to touch the ground during work, functioning as brakes that prevent movement by the wheels.

[0004] From the viewpoint of ensuring safety, such a leg extension mechanism is provided with a locking mechanism that prevents unintended sliding movement of the leg, and many are also commercially available with a double locking mechanism that further locks this locking mechanism. For example, the following patent document 1 can be cited as a patent document related to such a double locking mechanism. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-052581 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, a typical double lock mechanism such as that described in [Patent Document 1] requires an additional double lock after normal locking. In other words, two actions are required when locking: a locking action for the normal lock and a locking action for the double lock. For this reason, there is a possibility that a user may use the work tool with only the normal lock without performing the double lock, and further improvements are desired from the viewpoint of ensuring safety.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a double lock mechanism that can lock both the normal lock and the double lock simultaneously with one action while still requiring two actions to release the lock, as in the past, and a work tool equipped with the same. [Means for solving the problem]

[0008] The present invention relates to (1) A double locking mechanism 80 for locking the sliding movement of a leg 12 installed at the bottom of a vertical support 2 of a work tool, A rack gear 20 provided on the leg portion 12; a first locking member 30 provided on the vertical support 2 side, having engagement teeth 32, and rotating between a locked position where the engagement teeth 32 engage with the rack gear 20 and an unlocked position where the engagement teeth 32 are separated from the rack gear 20; a first elastic member 34 that biases the first locking member 30 toward the locked position; a second locking member 40 that moves between a rotation locking position that prevents the first locking member 30 from rotating and a rotation unlocking position that allows the first locking member 30 to rotate; and a second elastic member 44 that biases the second locking member 40 in the direction of the rotation locking position, The above problem is solved by providing a double lock mechanism 80, characterized in that when the first locking member 30 is released from the unlocked position with the leg portion 12 unlocked, the first elastic member 34 automatically rotates the first locking member 30 to the locked position and the second elastic member 44 automatically moves the second locking member 40 to the rotated locked position, thereby automatically double locking the leg portion 12. (2) A rotation space 42 for the first locking member 30 to rotate is provided, and a receiving portion 38 with which the second locking member 40 abuts is provided on a part of the first locking member 30 facing the rotation space 42, When the first locking member 30 is in the locked position, the second locking member 40 abuts against the receiving portion 38 to take the pivoted locked position, The above problem is solved by providing the double lock mechanism 80 described in (1) above, characterized in that when the first locking member 30 is in the unlocked position, the first locking member 30 blocks the rotation space 42 to prevent the second locking member 40 from moving to the rotation locked position. (3) The above problem is solved by providing the double lock mechanism 80 described in (1) above, characterized in that the second lock member 40 slides and moves within the housing portion 39 provided inside the first lock member 30. (4) A ladder member 10 including left and right vertical posts 2, a step 4 stretched between the left and right vertical posts 2, and a leg 12 installed at the bottom of the vertical posts 2 and sliding along the vertical posts 2; The above problem is solved by providing a work tool 100 having a double lock mechanism 80 described in any one of (1) to (3) above that locks the sliding movement of the leg 12. (5) The above problem is solved by providing a work tool 100 comprising a plurality of vertical supports 2, a base plate 7 held by the plurality of vertical supports 2, legs 12 installed at the lower parts of the vertical supports 2 and slidingly moving along the vertical supports 2, and a double locking mechanism 80 as described in any one of (1) to (3) above that locks the sliding movement of the legs 12. Effect of the Invention

[0009] The double lock mechanism and work tool equipped with the same according to the present invention automatically double locks with the first locking member and the second locking member with just one action of releasing the first locking member when the leg is locked. This prevents users from forgetting to lock the double lock, and allows them to use the work tool in a safe state with the double lock always engaged. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example in which the implement according to the present invention is applied to a step for a truck. [Diagram 2] FIG. 1 is a diagram showing an example in which the working tool according to the present invention is applied to a fruit sorting table. [Diagram 3] FIG. 13 illustrates a double locking mechanism according to the present invention. [Figure 4] 3A and 3B are an enlarged view and a schematic cross-sectional view of a double locking mechanism according to the present invention; [Diagram 5] 1A and 1B are a perspective view and a schematic cross-sectional view of a double-locking state of a double-locking mechanism according to the present invention; [Figure 6] 3A and 3B are a perspective view and a schematic cross-sectional view of a second locking member of the double locking mechanism according to the present invention in an unlocked state. [Figure 7] 3A and 3B are a perspective view and a schematic cross-sectional view of the double locking mechanism according to the present invention in an unlocked state. [Figure 8] 1A and 1B are diagrams showing a first locking member and a second locking member suitable for the double locking mechanism according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of a double lock mechanism 80 and a working tool 100 according to the present invention will be described with reference to the drawings. Here, Fig. 1 is a diagram showing an example in which the working tool 100 according to the present invention is applied to a truck lift step. Fig. 2 is a diagram showing an example in which the working tool 100 according to the present invention is applied to a fruit sorting table. The working tool 100 according to the present invention is not limited to a truck lift step and a fruit sorting table, but can be applied to all working tools 100 equipped with legs 12 that slide along a vertical support 2, such as ladders, stepladders, platforms, high-altitude work platforms, scaffolding, work platforms, mobile racks, and towing dollies.

[0012] First, a working tool 100 serving as a climbing step for a truck shown in Fig. 1 has a ladder member 10 as a main component. The ladder member 10 of the present invention has a pair of left and right vertical posts 2, a plurality of treads 4 stretched between the left and right vertical posts 2, legs 12 that are installed at the lower parts of the vertical posts 2 and extend and retract by sliding along the vertical posts 2, and a double locking mechanism 80 according to the present invention that individually locks the extension and retraction (sliding) of the legs 12.

[0013] In addition, when the working tool 100 according to the present invention is a step for climbing up and down a truck, a top plate 4a is provided on the upper end of the ladder member 10, and a hooking portion 6 is provided on the underside of the top plate 4a to fix the working tool 100 to the truck by hooking it onto the tailgate or the like of the truck. In terms of portability, it is preferable that the top plate 4a be foldable by rotating around a fulcrum provided on the vertical support 2. In addition, it is preferable that a handrail (not shown) is detachably or foldably provided on the vertical support 2 of the working tool 100 as a step for climbing up and down a truck. In addition, FIG. 1 shows an example in which the vertical support 2 is provided with a handrail joint 8, and by installing a handrail (not shown) on the handrail joint 8 during use, the user can climb up and down more safely.

[0014] 2 includes a plurality of (four) vertical supports 2, a base plate 7 held by the vertical supports 2, legs 12 installed at the lower portions of the vertical supports 2 and sliding along the vertical supports 2, and a double lock mechanism 80 according to the present invention that locks the sliding movement of the legs 12. The vertical supports 2 are connected in pairs to the base plate 7 in the short side direction and are pivotally supported on the base plate 7 so as to be rotatable. When stored, the pair of vertical supports 2 rotate toward the base plate 7 and are folded to assume a stored state. When used, the pair of vertical supports 2 are deployed outward and fixed in a predetermined position to assume a usage state.

[0015] Next, the double lock mechanism 80 according to the present invention will be described. Here, Fig. 3(a)-(e) are a top view, a front view, a side view, a back view, and a bottom view of the double lock mechanism 80 according to the present invention. Fig. 4(a) is an enlarged view of the front view, and Fig. 4(b) is a schematic cross-sectional view taken along line XX. Fig. 5(a) and (b) are a perspective view and a schematic cross-sectional view showing the double lock mechanism 80 in a double lock state, Fig. 6(a) and (b) are a perspective view and a schematic cross-sectional view showing the unlocked state of the second lock member of the double lock mechanism 80, and Fig. 7(a) and (b) are a perspective view and a schematic cross-sectional view showing the unlocked state of the double lock mechanism 80. In Fig. 5(a), Fig. 6(a), and Fig. 7(a), the mounting bracket 16 is shown in a see-through state by a broken line, and in Fig. 5(b), Fig. 6(b), and Fig. 7(b), the second elastic member 44 is partially omitted.

[0016] First, the double lock mechanism 80 according to the present invention individually locks the sliding movement (extension and retraction) of the leg 12 constituting the working tool 100. The leg 12 has a grounding part 12a located at the lower end and contacting the ground or floor surface, and a leg tube 2a through which the leg 12 moves in and out to slide. Although Figs. 1 and 2 show an example in which the leg tube 2a is configured as a separate body fixed parallel to the vertical support 2, the leg 12 may be configured to be directly movable in and out of the vertical support 2, so that the vertical support 2 also serves as the leg tube 2a. The leg 12 moves in and out of the leg tube 2a, so that the position of the grounding part 12a moves in and out of the vertical support 2 and slides up and down along the vertical support 2, thereby causing the leg 12 to move in and out of the leg tube 2a.

[0017] The double lock mechanism 80 according to the present invention is provided for each leg 12 that expands and contracts, and includes a rack gear 20 provided on one surface of the leg 12 (usually the surface located on the inside of a pair of legs 12), a first locking member 30 that engages with the rack gear 20, a first elastic member 34 that urges the first locking member 30 toward the locked position, a second locking member 40 that prevents the first locking member 30 from rotating, and a second elastic member 44 that urges the second locking member 40 toward a rotational locked position described below. The double lock mechanism 80 is fixed to the leg tube 2a via, for example, a substantially U-shaped mounting bracket 16.

[0018] As shown in Fig. 8(a), the first locking member 30 suitable for the present invention has an engagement tooth 32 that engages with the rack gear 20 at one end protruding toward the leg tube 2a, and a rotating lever 36 that allows a person to rotate the first locking member 30 is provided at the other end (the opposite end of the engagement tooth 32) protruding in the opposite direction to the leg tube 2a. The first locking member 30 is supported by a shaft body 22, which is supported by a shaft hole 22a provided in the mounting bracket 16, for example, as shown in Figs. 5 to 7, and held on the leg tube 2a (vertical support 2) side. The first locking member 30 rotates between a locked position shown in Figs. 4 to 6, in which the engagement tooth 32 engages with the rack gear 20, and an unlocked position shown in Fig. 7, in which the rotating lever 36 is pushed down toward the leg tube 2a, the engagement tooth 32 is lifted, and separated from the rack gear 20. When the first locking member 30 is in the locked position, a rotation space 42 for the first locking member 30 to rotate is formed between the rotating lever 36 and the leg tube 2a. At this time, it is preferable to provide a receiving portion 38 against which the second locking member 40 abuts at a predetermined position of the first locking member 30 facing the rotation space 42. The receiving portion 38 is preferably shaped as a recess having approximately the same diameter as the slide pin 48, but may be simply a surface. In the configuration in which the receiving portion 38 is provided, when the first locking member 30 is in the locked position, the slide pin 48 and the receiving portion 38 engage with each other, so that the rotation of the first locking member 30 and the movement of the second locking member 40 can be more reliably prevented.

[0019] Furthermore, the first locking member 30 suitable for the present invention is preferably provided with a substantially rectangular housing portion 39 inside for housing the second locking member 40. In this case, the first locking member 30 is substantially square-shaped in front view, composed of a tip portion equipped with engagement teeth 32, a push button portion of the rotating lever 36, and left and right arms of the rotating lever 36.

[0020] A first elastic member 34 is provided on the first locking member 30, and biases the first locking member 30 in the direction of the locked position. There is no particular limitation on the first elastic member 34 used in this case, but it is preferable to use a "torsion coil spring" held by passing a coil portion through the shaft body 22. Then, in a released state in which the user releases the first locking member 30, the first locking member 30 automatically rotates to the locked position by the elastic force of the first elastic member 34, and the engagement teeth 32 engage with the rack gear 20 to lock the sliding movement of the leg 12.

[0021] As shown in FIG. 8(b), the second locking member 40 suitable for the present invention has a main body 40a, a slide lever 46 for allowing the user to slide the main body 40a, and a slide pin 48 protruding from the main body 40a in the left-right direction. In the second locking member 40 suitable for the present invention, the main body 40a is preferably configured in a substantially U-shape with the leg tube 2a side open, and the slide pin 48 is preferably formed of a metal rod penetrating the main body 40a in the left-right direction. The second locking member 40 is installed in a slidable state in the housing portion 39 of the first locking member 30. The mounting bracket 16 is provided with a long hole 48a parallel to the longitudinal direction of the vertical support 2, and the slide pin 48 is movably inserted into the long hole 48a by passing under the left and right arms of the rotating lever 36. This allows the second locking member 40 to slide along the longitudinal direction of the vertical support 2 by being guided by the long hole 48a. The second locking member 40 slides between a rotation locked position where the slide pin 48 enters the rotation space 42 and abuts against the receiving portion 38, and a rotation unlocked position where the slide pin 48 disengages from the rotation space 42. In this case, it is preferable to provide a step in the rotation lever 36, and to make the surface of the step in the rotation lever 36 approximately the same as the end face position of the slide lever 46 when the second locking member 40 is in the rotation unlocked position, as shown in Figure 6. With this configuration, the user can intuitively know how far the slide lever 46 needs to be slid to reach the rotation unlocked position.

[0022] The second elastic member 44 biases the second locking member 40 in the direction of the above-mentioned rotation locking position. There is no particular limitation on the second elastic member 44 used in this case, but it is preferable to use a "tension coil spring" with one end held by the first locking member 30 side and the other end held by the second locking member 40 side. In the second locking member 40 suitable for the present invention, it is preferable that one end of the second elastic member 44 is inserted inside the main body portion 40a opened in a U-shape and hooked and held by a slide pin 48 penetrating the main body portion 40a, and the other end is hooked and held by the shaft body 22 of the first locking member 30. With this configuration, the number of parts of the double locking mechanism 80 according to the present invention can be reduced, and space-saving and compactness can be achieved.

[0023] When the first locking member 30 is in the locked position, the rotating lever 36 is in a raised state, and a rotation space 42 is formed in the area below the receiving parts 38 of the left and right arms of the rotating lever 36. The slide pin 48 of the second locking member 40 enters the rotation space 42 and abuts against the receiving parts 38 to assume the locked position. In the locked position, the second locking member 40 (slide pin 48) is located between the rotating lever 36 and the leg tube 2a, so the first locking member 30 cannot rotate from the locked position due to the slide pin 48 being an obstacle, and cannot assume the unlocked position. As a result, the leg 12 is doubly locked by the first locking member 30 and by the second locking member 40 locking the first locking member 30.

[0024] Next, the operation of the double lock mechanism 80 according to the present invention will be described using examples of a truck lift step and a sorting table. First, the work tool 100 is placed at the place of use. At this time, the leg 12 is in a contracted state housed in the leg tube 2a. At this time, as shown in Figures 4 and 5, the double lock mechanism 80 is in a locked position in which the engagement teeth 32 of the first lock member 30 are engaged with the rack gear 20 of the leg 12, and the second lock member 40 is in a pivoted locked position in which it abuts against the receiving portion 38 of the first lock member 30, so that the leg 12 is doubly locked by the first lock member 30 and the second lock member 40 of the double lock mechanism 80.

[0025] Next, if the working tool 100 is a truck climbing step, the top plate 4a is rotated from the folded state to the unfolded state, and the hooking portion 6 of the top plate 4a is hooked onto the tailgate or the like of the truck where the working tool 100 is to be installed. Also, if the working tool 100 is a sorting table, the two paired vertical supports 2 are each unfolded outward. These vertical supports 2 are then fixed at predetermined positions rising from the base plate 7, and become the legs of the base plate 7. Next, the double locking mechanism 80 of the legs 12 of the working tool 100 is released in the following procedure.

[0026] To release the double locking mechanism 80, the user first pushes the slide lever 46 of the second locking member 40 upward along the vertical support 2. This causes the slide pin 48 of the second locking member 40 to slide upward using the long hole 48a of the mounting bracket 16 as a guide. This causes the slide pin 48 to disengage from the receiving portion 38 of the first locking member 30 as shown in Figure 6, and the second locking member 40 reaches the rotation unlocked position. Then, the first locking member 30 can be rotated.

[0027] Next, while holding the second locking member 40 in the rotation unlocked position, the user pushes down the rotating lever 36 toward the leg tube 2a as shown in Fig. 7. This causes the first locking member 30 to rotate about the shaft body 22, causing the engagement teeth 32 to rise and disengage from the rack gear 20 to assume the unlocked position. In this unlocked position, the engagement teeth 32 and the rack gear 20 are separated, so that the leg 12 is unlocked and can slide relative to the leg tube 2a. Next, the user releases the second locking member 40 while still holding down the rotating lever 36. As a result, the second locking member 40 tries to slide toward the rotation locking position due to the restoring force of the second elastic member 44, but when the rotation lever 36 is pressed down, the area corresponding to the rotation space 42 is blocked by the rotation lever 36, and the second locking member 40 comes into contact with the first locking member 30 just before the rotation locking position as shown in Figure 7, preventing the second locking member 40 from moving to the rotation locking position. As a result, the first locking member 30 remains in the unlocked position, and the unlocked state of the leg 12 is maintained.

[0028] Next, the user slides the leg 12 in and out of the leg tube 2a along the vertical support 2, and sets the ground contact portion 12a to, for example, an optimal position where the work tool 100 is stable, or an optimal height position where the user can work easily. Next, the user releases the rotating lever 36. As a result, the first locking member 30 automatically rotates to the locked position due to the restoring force of the first elastic member 34. Then, the engagement teeth 32 and the rack gear 20 engage with each other to lock the leg 12. In addition, the first locking member 30 rotates to the locked position, and the rotating lever 36 is lifted, and the rotating space 42 is opened. As a result, the second locking member 40 slides due to the elastic force of the second elastic member 44, enters the rotating space 42, and abuts against the receiving portion 38 to the rotating locking position. As a result, the first locking member 30 cannot rotate from the locked position, and the first locking member 30 is locked. As a result, the leg 12 is locked by the first locking member 30, and the first locking member 30 is further locked by the second locking member 40, resulting in a double locking state.

[0029] Next, the user unlocks the double locking mechanism 80, adjusts the position of the ground contact portion 12a, and locks the double locking mechanism 80 for all legs 12 of the working tool 100. As a result, if the working tool 100 is a truck climbing step, the tread 4 and the top plate 4a are placed in a stable, substantially horizontal position, allowing the user to climb up and down and work safely. Also, if the working tool 100 is a fruit sorting table, the base plate 7 is placed at a height that is easy to work on.

[0030] Moreover, the double lock mechanism 80 according to the present invention is preferably configured such that the second locking member 40 has a pivot locking position at the bottom and an unlocked position at the top when the work tool 100 is in use. In this configuration, even if the second elastic member 44 is broken, the second locking member 40 is pressed toward the first locking member 30 by the weight and load of the work tool 100 and is held in the pivot locking position. As a result, the first locking member 30 is held in the locked position, and even if the second elastic member 44 is broken, the locked state with respect to the leg 12 is maintained. Also, even if the first elastic member 34 is broken, since the second locking member 40 is in the pivot locking position, the first locking member 30 is held in the locked position, and the locked state with respect to the leg 12 is maintained. In this way, the double lock mechanism 80 according to the present invention can maintain the locked state with respect to the leg 12 even if the first elastic member 34 or the second elastic member 44 is broken.

[0031] As described above, the double lock mechanism 80 according to the present invention and the work tool 100 equipped with the same require two actions by the user to release the lock on the leg 12, as in the case of a conventional double lock mechanism. However, when the leg 12 is to be locked, the user only needs to release the first locking member 30 held in the unlocked position, and the first locking member 30 automatically rotates to the locked position by the restoring force of the first elastic member 34 to lock the leg 12, and the rotation of the first locking member 30 opens the rotation space 42, and the second locking member 40 automatically slides to the rotated lock position by the elastic force of the second elastic member 44 to lock the first locking member 30. That is, in the double lock mechanism 80 according to the present invention and the work tool 100 equipped with the same, the double locking by the first locking member 30 and the second locking member 40 is automatically performed by only one action of releasing the first locking member 30 held when the leg 12 is locked. This prevents the user from forgetting to double-lock the work tool 100, and allows the user to use the work tool 100 in a safe state with the double lock always engaged.

[0032] It should be noted that the configurations, shapes, designs, etc. of the double locking mechanism 80 and the work tool 100 shown above are merely examples and are not limited to the above examples. The present invention can be modified and implemented without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0033] 2 Vertical Supports 4. Stepping Rail 7 Base plate 10 Ladder members 12 Legs 20 Rack Gear 30 First lock member 32 Engagement teeth 34 First elastic member 38 Receiving Department 39 Storage unit 40 Second lock member 42 Rotation space 44 Second elastic member 80 Double lock mechanism 100 Work tools

Claims

1. A double locking mechanism for locking the sliding movement of a leg part installed at the lower part of a vertical support of a work tool, A rack gear provided on the leg; a first locking member provided on the vertical support pillar, having engagement teeth, and rotating between a locked position in which the engagement teeth engage with the rack gear and an unlocked position in which the engagement teeth are separated from the rack gear; a first elastic member that biases the first locking member toward a locked position; a second locking member that moves between a rotationally locked position that prevents the first locking member from rotating and a rotationally unlocked position that allows the first locking member to rotate; a second elastic member that biases the second locking member in the direction of the rotation locking position, A double lock mechanism characterized in that, when the first locking member is released from the unlocked position while the leg portion is in an unlocked state, the first elastic member automatically rotates the first locking member to the locked position and the second elastic member automatically moves the second locking member to the rotated locked position, thereby automatically double locking the leg portion.

2. a rotation space for the first locking member to rotate is provided, and a receiving portion for contacting the second locking member is provided on a part of the first locking member facing the rotation space; When the first locking member is in the locked position, the second locking member abuts against the receiving portion to assume a pivoted locked position; 2. The double lock mechanism according to claim 1, wherein when the first locking member is in the unlocked position, the first locking member blocks the rotation space to prevent the second locking member from moving to the locked position.

3. 2. The double locking mechanism according to claim 1, wherein the second locking member slides within a receiving portion provided inside the first locking member.

4. A ladder member including left and right vertical posts, a step spanned between the left and right vertical posts, and a leg portion installed at the lower portion of the vertical posts and sliding along the vertical posts; and a double lock mechanism according to any one of claims 1 to 3, which locks the sliding movement of the leg.

5. 4. A work tool comprising: a plurality of vertical supports; a base plate supported by the plurality of vertical supports; legs installed at lower portions of the vertical supports and slidingly moving along the vertical supports; and a double locking mechanism according to any one of claims 1 to 3 that locks the sliding movement of the legs.

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