Lifting rack

Abstract

To provide a lifting rack capable of interlocking a pair of right and left arms.SOLUTION: The present invention is directed to a lifting rack in which a lifting link mechanism 5, which supports a lifting rack main body 1 so that it can be raised and lowered relative to a fixed rack 9, includes fixed plates 41 on both sides, an upper arm 2, and a lower arm 3. The base ends of both the upper and lower arms 2 and 3 are rotatably attached to the fixed plates 41 on both sides, and the tip ends are rotatably attached to both side portions of the lifting rack main body 1. A fixed rotating plate is rotatably attached to a position behind the upper arm on the fixed plates 41. The tip end of a cord-like body, which is suspended over the upper side of the fixed rotating plate, is attached to the tip end of either the upper arm 2 or the lower arm 3, and each base end of the cord-like body is attached to the fixed plates 41. Tension adjustment means is provided to apply a predetermined tension to the cord-like body regardless of the rotational positions of the upper and lower arms 2 and 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lift-up rack that can be attached to a fixed rack used in, for example, a factory or warehouse, and that can utilize the top plate of the fixed rack as storage space. [Background technology]

[0002] In factories, warehouses, etc., fixed racks are installed for storing and safekeeping items, but as shown in Patent Documents 1 and 2, in such fixed racks, a lifting rack may also be attached to the top plate so that items can be stably stored. The lifting rack includes a lifting rack body and a lifting link mechanism that supports the lifting rack body so that it can be raised and lowered freely.

[0003] The lifting / lowering link mechanism includes a pair of left and right base members fixed to the top plate of the fixed rack, a pair of left and right upper arms, and a pair of left and right lower arms, with the base ends of the upper and lower arms rotatably attached to the base members and the tip ends rotatably attached to both sides of the lifting / lowering rack body. The tip ends of the upper and lower arms rotate upward to place the lifting / lowering rack body in a storage position on the top plate of the fixed rack, and the upper and lower arms rotate downward to place the lifting / lowering rack body in a pull-out position in front of the fixed rack. The lifting / lowering link mechanism is provided with a biasing means for biasing the lifting / lowering rack body upward, and the biasing force of the biasing means is configured to prevent the lifting / lowering rack body including stored items from suddenly dropping when it is pulled out, and to reduce the load (burden) when the lifting / lowering rack body is lifted.

[0004] In the above-mentioned conventional lift rack, the lift rack body is supported between a pair of left and right arms in the lift link mechanism. Therefore, if, for example, the storage position of the stored items is uneven, the load of the lift rack body cannot be supported evenly by the pair of left and right arms, and the left and right weight balance is disturbed, the pair of left and right arms do not synchronize precisely, causing a misalignment in the rotational movement, making it difficult to operate the lift rack body smoothly.

[0005] Therefore, in conventional lift racks, in order to synchronize the pair of left and right arms in the lift link mechanism, a configuration is adopted in which, for example, a connecting rod is fixed between the pair of upper arms to link the pair of upper arms together. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-98575 [Patent Document 2] Japanese Patent Application Publication No. 11-318589 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the above-mentioned conventional lift rack, since the connecting rod is fixed between the movable parts such as the pair of upper arms, the connecting rod also moves following the lifting and lowering of the lift rack main body (rotation of the arms). Since a movable connecting rod exists between the pair of left and right arms in this way, there was a problem that the structure between the pair of arms becomes complicated, which may lead to a complication of the structure of the entire lift rack.

[0008] This invention has been made in consideration of the above-mentioned problems, and aims to provide a lifting rack that can accurately link and synchronize a pair of left and right arms in a lifting link mechanism, and further, can simplify the structure between the pair of left and right arms. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention comprises the following means.

[0010] [1] A lift-and-lower rack comprising a lift-and-lower rack body and a lift-and-lower link mechanism supporting the lift-and-lower rack body so as to be freely raised and lowered relative to a fixed rack, the lift-and-lower link mechanism including fixed plates fixed to both sides of the upper part of the fixed rack, a pair of upper arms on the left and right, and a pair of lower arms on the left and right, the base ends of the upper and lower arms being rotatably attached to the fixed plates on the left and right, respectively, and the tip ends of the upper and lower arms being rotatably attached to both sides of the lift-and-lower rack body, respectively, such that when the upper and lower arms rotate upward, the lift-and-lower rack body is disposed in a storage position above the fixed rack, and when the upper and lower arms rotate downward, the lift-and-lower rack body is disposed in an extended position in front of the fixed rack, A pair of left and right stationary rotating disks are rotatably attached to the rear of the pair of upper arms of the both side fixing plates, A pair of stationary rotating disks are connected by a connecting shaft and configured to rotate in conjunction with each other, The tip ends of a pair of cord-like bodies, which are hung on the upper sides of the pair of stationary rotating plates, are attached to the tip ends of either of the upper and lower arms, and the base ends of the cord-like bodies are attached to the two side fixing plates, A lift rack characterized in that a pair of cord-like bodies are each provided with a tension adjustment means for applying a predetermined tension to the pair of cord-like bodies regardless of the rotational positions of the upper and lower arms.

[0011] [2] The tension adjusting means includes a tension biasing means provided between the base end side of the cord-like body and the two side fixed plates, and tension-biasing the cord-like body toward the base end side, and a movable rotating disk attached between the fixed rotating disk and the tension biasing means on the two side fixed plates so as to be movable in the vertical direction, and on the lower side of which the cord-like body is hung, A lifting rack as described in the preceding paragraph 1, which is configured such that the length of the cord-like body on the tip side of the fixed turntable and the length on the base side are complementarily changed by raising and lowering the movable turntable in the opposite direction to the raising and lowering movement of the lifting rack body, thereby keeping the overall length constant.

[0012] [3] A lifting rack as described in paragraph 2, wherein the fixed turntable and the movable turntable are formed by sprockets, and the cord-like body is formed by a chain.

[0013] [4] An upward biasing means for biasing the lifting rack body upward during lifting and lowering operation, 4. The lifting rack according to any one of items 1 to 3 above, wherein the upward biasing means is constituted by a constant load winding spring whose winding tension is constant regardless of the amount of pulling out.

[0014] [5] The pair of lower arms are disposed inside the pair of upper arms, A lift rack described in any one of items 1 to 4, wherein guide pieces provided on a pair of lower arms are arranged along the inner surfaces of a pair of upper arms, thereby preventing left-right positional shifting of the pair of upper arms relative to the pair of lower arms. Effect of the Invention

[0015] According to the lifting rack of the invention [1], a pair of stationary rotating plates connected to the left and right by a connecting shaft is attached to the fixed plates on both sides, and the tip side of the rope-like body hung on the stationary rotating plates is attached to either the upper arm or the lower arm, respectively, and a tension adjustment means is provided for maintaining a constant tension on the rope-like body regardless of the rotation position of the arm. Therefore, the left and right rope-like bodies are sent out and retracted in a synchronized manner following the rotation of the arm on one side. Therefore, when the lifting rack body is raised and lowered, the pair of left and right arms in the lifting link mechanism operate in a synchronized manner accurately, and the lifting rack body can be raised and lowered smoothly. Furthermore, since the pair of left and right arms are linked by the sending and retracting movements of the rope-like body provided on the fixed plates on both sides, there is no connecting rod between the pair of left and right arms that moves with the rotation of the arms, and the structure between the pair of left and right arms and the structure of the lifting rack itself can be simplified. The connecting shaft connecting the stationary rotating plates is fixed in position regardless of the rotation of the arms.

[0016] According to the lifting rack of the invention [2], a movable turntable that moves up and down in the opposite direction to the lifting and lowering movement of the lifting rack body is provided on the rear side of the stationary turntable. A cord-like body is hung on the underside of the movable turntable, and the rear end side of the cord-like body is attached to a fixed plate via a tension biasing means, so that the total length of the cord-like body is adjusted and a predetermined tension is applied to the cord-like body. This makes it possible to adjust the tension of the cord-like body with a simple and flexible structure, and improves operational reliability.

[0017] According to the lift rack of the invention [3], the effects of the above inventions [1] and [2] can be obtained more reliably.

[0018] According to the lift rack of the invention [4], the lift rack body can be raised and lowered smoothly and effortlessly.

[0019] According to the lift rack of invention [5], when the upper and lower arms rotate up and down, the guide pieces on both sides slide along the inner surfaces of the upper arms on both sides, thereby positioning the upper arm left and right relative to the lower arm and preventing misalignment in the left and right direction. This makes it possible to rotate the upper and lower arms, and ultimately to raise and lower the lift rack body, even smoother. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a side view showing a rack device to which a lifting rack according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a front view showing the rack device according to the embodiment. [Diagram 3] FIG. 3 is a top view showing the rack device according to the embodiment. [Figure 4] FIG. 4 is a side view showing a state in which the rack body is pulled out in the rack device of the embodiment. [Diagram 5] FIG. 5 is a front view showing a fixing unit applied to the lift-up rack of the embodiment. [Figure 6] FIG. 6 is a side view showing the fixing unit of the embodiment. [Figure 7] FIG. 7 is a front view showing a lift-up rack main body applied to the lift-up rack of the embodiment. [Figure 8] FIG. 8 is a side view showing the lifting rack body of the embodiment. [Figure 9] FIG. 9 is a side view showing a schematic view of the lift-up rack in the storage position in the embodiment. [Figure 10] FIG. 10 is a side view showing a schematic diagram of a lifting rack in the middle of being lifted or lowered in the embodiment. [Figure 11] FIG. 11 is a side view showing a schematic diagram of the lift-up rack in the pulled-out position in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] 1 to 4 are diagrams showing a rack device to which a lift-up rack according to an embodiment of the present invention is applied. As shown in these figures, the lift-up rack according to this embodiment is attached to a fixed rack 9 installed in a factory or warehouse. The lift-up rack according to this embodiment includes a lift-up rack body 1 and a lift-up link mechanism 5 that supports the lift-up rack body 1 so as to be freely raised and lowered relative to the fixed rack 9. The lift-up link mechanism 5 allows the lift-up rack body 1 to be raised and lowered between a storage position on the top plate of the fixed rack 9 shown in FIG. 1 and a pull-out position on the front side of the fixed rack 9 shown in FIG. 4, and is also configured to be supported in either the storage position or the pull-out position.

[0022] In order to facilitate understanding of the invention, in this embodiment, the left side on the paper surface of FIG. 1 will be referred to as the "front side", the right side on the paper surface of FIG. 1 will be referred to as the "rear side", and the left and right directions on the paper surface of FIG. 2 will be referred to as the "left and right direction" or "both sides".

[0023] As shown in Figs. 1 to 6, the lifting link mechanism 5 includes a fixed unit 4 fixed to the top plate of the fixed rack 9. The fixed unit 4 includes both side fixed plates 41 arranged on the left and right, and an upper front rail 42 is fixed between the upper front parts of the both side fixed plates 41 in a bridge-like manner, and a winding spring (spiral spring) 43 is attached to both sides of the upper front rail 42 as an upward biasing means. The winding spring 43 has a drum 44 provided at the fixed side end, and the drum 44 is attached to the upper front rail 42, and the drawn-out end 441 (see Fig. 4) of the winding spring 43 is attached to the lifting rack main body 1 as described later. In this embodiment, the winding spring 43 is configured by a constant load spring (Conston spring "product name") whose winding force is constant regardless of the drawn-out amount.

[0024] A lower front rail 45 is fixed in a bridging manner between the lower ends of both side fixing plates 41 of the fixing unit 4. A lock piece 46 (see Figs. 4 to 6) is attached to the front middle part of this lower front rail 45 so as to protrude downward.

[0025] An upper and lower guide groove 47 extending in the vertical direction is formed in both side fixing plates 41 of the fixing unit 4. This guide groove 47 is shaped so that the middle part is curved rearward more than both upper and lower ends, and is formed in an arc shape centered on the rotation fulcrum of the upper arm 2 described later.

[0026] Furthermore, front-rear guide grooves 48 extending in the front-rear direction are formed in both side fixing plates 41 of the fixing unit 4. This guide groove 48 is shaped so that the middle part is curved upward more than both front and rear ends, and is formed in an arc shape centered on the rotation fulcrum of the upper arm 2 described later.

[0027] The upper and lower guide grooves 47 and the front and rear guide grooves 48 are formed in the fixed plates 41 on both sides so as to correspond to each other.

[0028] As shown in FIG. 1, FIG. 4 and the like, the fixed unit 4 having this configuration is fixed onto the top plate of a fixed rack 9 by bolts or the like.

[0029] Fig. 7 is a front view showing the lift-up rack main body 1 applied to the lift-up rack of the embodiment, and Fig. 8 is a side view. As shown in Figs. 1 to 4, 7 and 8, the lift-up rack main body 1 is formed to a size that can be accommodated in the fixed unit 4, and includes a bottom plate 10, both side plates 11 attached to both side edges of the bottom plate 10 in a rising shape, and a back plate 12 attached to the rear end edge of the bottom plate 10 between the both side plates 11 in a rising shape.

[0030] Furthermore, a handle device 15 is attached to the lower surface side of the lifting rack main body 1. The handle device 15 includes a pair of left and right levers 16. The levers 16 are formed in an L-shape with a vertical portion 161 extending downward and a horizontal portion 162 extending rearward from the upper end of the vertical piece. The bent portions of the pair of levers 16 are connected to each other by a rotating shaft 17, and this rotating shaft 17 is rotatably attached to the lower surface of the bottom plate of the lifting rack main body 1, so that the pair of levers 16 swing in synchronization. Furthermore, a grip shaft 18 (see Figures 2 and 7, etc.) is attached in a bridging manner between the lower ends of the vertical portions of the pair of levers 16, so that an operator can hold the grip shaft 18 by hand to swing the levers 16 or raise and lower the lifting rack main body 1.

[0031] The handle device 15 is provided with a hook 19 that protrudes upward from the rear end of the horizontal portion 16 of the lever 16. The handle device 15 is further provided with a biasing means 191 (see Figs. 1 and 8, etc.) such as a tension coil spring for urging the lever 16 to rotate with the hook 19 side toward the upper side (counterclockwise direction in Fig. 7). As shown in Fig. 1, etc., when the lifting rack body 1 is arranged in the storage position on the fixed rack 9, the hook 19 is biased upward by the biasing force of the biasing means 191 and is configured to engage with the lock piece 46 of the fixed unit 4. In this engaged state (locked state), the lifting rack body 1 is configured to be prevented from inadvertently descending from the storage state (raised state). In this locked state, the operator holds the grip shaft 18 by hand and rotates the lever 16 toward himself against the biasing force of the biasing means 191 (see imaginary line in Fig. 8), so that the hook 19 moves away from the lock piece 46 and the lock is released.

[0032] 9 to 11 are schematic side views for explaining the operation of the lift-up rack of the embodiment. As shown in Figs. 1 to 4 and 9 to 11, the lift-up link mechanism 5 that supports the lift-up rack main body 1 so that it can be raised and lowered includes a pair of left and right upper arms 2 and a pair of left and right lower arms 3. The upper arms 2 have a base end support portion 21 rotatably attached to the inner surface of both side fixing plates 41 of the fixing unit 4. Furthermore, the tip side swinging portion 22 of the upper arm 2 is rotatably attached to the upper end of an upwardly protruding mounting piece 111 provided at the front of both side plates 11 of the lift-up rack main body 1.

[0033] The lower arm 3 is disposed inside the upper arm 2. The base end pivot portion 31 of the lower arm 3 is rotatably attached to the inner surface of both side fixed plates 41 of the fixed unit 4 below the base end pivot portion 21 of the upper arm 2. Furthermore, the tip side swing portion 32 of the lower arm 3 is rotatably attached to both side plates 11 of the lifting rack main body 1 below the tip side swing portion 22 of the upper arm 2. As a result, the upper and lower arms 2, 3 swing upward with the tip-side swinging portions 22, 33 pivoting around the base-end support portions 21, 31 as fulcrums, thereby positioning the lift-up rack main body 1 in a stored position (raised position) housed within the fixed unit 4 on the top plate of the fixed rack 9, as shown in Figures 1 and 9, while the upper and lower arms 2, 3 swing downward with the tip-side swinging portions 22, 32 pivoting around the base-end support portions 21, 31 as fulcrums, thereby positioning the lift-up rack main body 1 in a withdrawn position (lowered position) located in front of the fixed rack 9, as shown in Figures 4 and 10.

[0034] As described above, when the lift-up / lowering rack body 1 is in the storage position, the hook 19 engages with the lock piece 46, and the lowering operation of the lift-up / lowering rack body 1 is restricted.

[0035] Furthermore, the pull-out ends 441 of the winding springs 43 provided on both sides of the upper front rail 42 of the fixed unit 4 are fixed to the rack top beam provided on the upper part of the lifting rack main body 1, and the lifting rack main body 1 is pulled upward by the biasing force of the winding springs 4. This makes it possible to prevent an inadvertent sudden descent without requiring a large amount of receiving force when lowering the lifting rack main body 1, and also makes it possible to lift the lifting rack main body 1 with a light operating force when raising it.

[0036] A guide piece 35 is formed near each base end support portion 31 of the pair of lower arms 3 so as to protrude rearward or upward (see Figs. 9 to 11, etc.), and the guide pieces 35 on both sides are disposed along the inner side surfaces of the pair of upper arms 2. When the upper and lower arms 2, 3 rotate up and down, the guide pieces 35 on both sides slide along the inner side surfaces of the upper arms 2 on both sides, thereby positioning the upper arm 2 in the left-right direction relative to the lower arm 3 and preventing misalignment in the left-right direction. Since misalignment of the upper and lower arms 2, 3 in the left-right direction is thus prevented, the upper and lower arms 2, 3 can be rotated smoothly.

[0037] A damper mounting piece 36 is formed on each of the upper arms 2 on both sides so as to protrude from the outer periphery of each base end support portion 21 such that its tip corresponds to the front-rear guide groove 48 of the both-side fixed plate 41 (see Figs. 1 and 4, etc.), and a movable member 37 that is slidably accommodated in the front-rear guide groove 48 is attached to the tip of this damper mounting piece 36. The movable member 37 moves along the front-rear guide groove 48 as the upper arm 2 rotates, and the movable member 37 is arranged to be located in a front-rear position of the front-rear guide groove 48 when the upper arm 2 is located in an up-down position.

[0038] Furthermore, the tip of the piston part of the oil damper 38 is rotatably attached to the movable member 37, and the cylinder part of the oil damper 38 is rotatably attached to the fixed plates 41 on both sides. This oil damper 38 expands and contracts more in the areas of the movable member 37 at both the front and rear ends of the front and rear guide grooves 48, and acts as an appropriate resistance force. In other words, it acts as a resistance force just before and after the lift-up rack main body 1 is placed in the storage position and just before and after it is placed in the pull-out position. This allows stable and smooth operation just before the start and end of the lift-up operation.

[0039] As described in detail below, the lifting rack of this embodiment uses a chain 6 as a cord-like member to synchronize and link the pair of left and right upper arms 2 and the pair of left and right lower arms 3 in the lifting link mechanism 5.

[0040] That is, a fixed sprocket (fixed rotating disk) 61 is rotatably attached to the upper end of the outer surface of each of the fixed plates 41. Furthermore, the rotating shafts of the fixed sprockets 61 on both the left and right sides are connected to each other by a connecting shaft 60, so that the fixed sprockets 61 on both sides rotate synchronously with each other.

[0041] Meanwhile, in the pair of upper arms 2, movable sprocket mounting pieces 25 extending in the opposite direction to the tip side swinging part 22 are formed on the disk-shaped base end side support part 21, and the tip of each movable sprocket mounting piece 25 is arranged corresponding to each upper and lower guide groove 47 of the both side fixed plates 41. A rotating shaft of a movable sprocket (movable rotating disk) 62 is attached to each of the movable sprocket mounting pieces 25, and each rotating shaft is housed so as to be slidable along each of the upper and lower guide grooves 47. As a result, when the tip side swinging part 22 of the pair of upper arms 2 swings up and down, the movable sprockets 62 are configured to move up and down along the upper and lower guide grooves 47 in the opposite direction (reverse direction) to the tip side swinging part 22.

[0042] Furthermore, the tip ends of a pair of chains 6 are rotatably attached to the tip sides of the pair of upper arms 2, the middle parts of each chain 6 are hung on the upper sides of each fixed bracket 61 and on the lower sides of each movable bracket 62, and the base ends of each chain 6 are rotatably attached to both side fixed plates 41 via tension coil springs 63 as tension biasing means.

[0043] In this configuration, as shown in Figures 4 and 11, when the pair of upper arms 2 swing downward as the lift-up rack body 1 descends and the chain 6 is sent forward from the fixed sprocket 61, the movable sprocket 62 slides upward, reducing the amount of downward sagging of the chain 6 between the fixed sprocket 61 and the tension coil spring 63. When the tip end of the chain 6 becomes longer than the fixed sprocket 61 as the lift-up rack body 1 descends, the base end of the chain 6 becomes shorter than the fixed sprocket 61, and the overall length of the chain 6 is kept constant. Conversely, as shown in Figures 1 and 9, when the pair of upper arms 2 swing upward as the lift-up rack body 1 ascends and the tip end of the chain 6 is pulled toward the fixed sprocket 61, the movable sprocket 62 slides downward, increasing the amount of downward sagging of the chain 6 between the fixed sprocket 61 and the tension coil spring 63. In this way, when the lifting rack body 1 rises, the tip side of the chain 6 becomes shorter than the fixed sprocket 61, and the base side of the chain 6 becomes longer than the fixed sprocket 61, and the overall length of the chain 6 is maintained constant.

[0044] As described above, in this embodiment, the movable sprocket 62 rises and falls in the opposite direction (reverse direction) in response to the raising and lowering movement of the lifting rack main body 1, so that the length of the chain 6 on the tip side beyond the fixed sprocket 61 and the length on the base end side change complementarily, thereby maintaining the overall length constant.

[0045] Furthermore, since the chain 6 is constantly biased by the biasing force of the tension coil spring 63, a predetermined tension is applied to the chain 6, thereby reliably preventing problems such as inadvertent slackening and excessive tension.

[0046] In this embodiment, the tension adjustment means is constituted by the tension coil spring 63 (tension biasing means) and the movable sprocket 62, on the lower side of which the chain 6 is hung and which moves up and down along the upper and lower guide grooves 47.

[0047] 1 and 9, in the storage state of the rack device of this embodiment having the above configuration, the upper and lower arms 2, 3 are rotated upward, and the lifting rack main body 1 is stored in the fixed unit 4 on the top plate of the fixed rack 9. Furthermore, in the storage state, the lever 16 of the handle device 15 of the lifting rack main body 1 is rotationally biased so that the rear end side thereof is lifted, and the hook 19 is engaged with the lock piece 46 of the fixed unit 4. In this engaged state, the lifting and lowering operation of the lifting rack main body 1 is restricted, and it is possible to prevent the lifting rack main body 1 from inadvertently falling.

[0048] To pull out the lifting rack body 1 from this stored state, the worker holds the grip shaft 18 of the handle device 15 of the lifting rack body 1 by hand, pulls the lever 16 toward himself, and rotates it to disengage the hook 19 of the lever 16 from the lock piece 46 of the fixed unit 4 to release the engagement. After releasing the engagement in this way, the lifting rack body 1 is lowered by holding the grip shaft 18 and pulling it toward himself. Immediately after starting this descent, the upper arm 2 is in a nearly vertical position, so the rotation moment is small, and resistance is applied by the oil damper 38, so that the lifting rack body 1 can be prevented from rapidly moving from the stored position into a lowering position, and the lowering operation of the lifting rack body 1 can be started smoothly. Next, as shown in FIG. 10, the worker holds the grip shaft 18 by hand and lowers the lifting rack body 1. During this descent, a biasing force in the lifting direction is applied by the constant load winding spring 43, so the operator does not need to directly bear the load including the lifting rack body 1 and the items stored therein, and can lower the lifting rack body 1 with a light operating force and place it in the pulled-out position shown in Figures 4 and 11. Just before the descent is complete, a resistance force is applied to the lifting rack body 1 by the oil damper 38 just before the pulled-out position, so the lifting rack body 1 does not move to the pulled-out position abruptly but slowly and gently, and the lifting rack body 1 can be placed in the pulled-out position in a stable state.

[0049] On the other hand, to store the lifting rack body 1 from the pull-out position onto the top plate of the fixed rack 9, the grip shaft 18 of the handle device 15 is held by hand to lift the lifting rack body 1. Immediately after the start of this lifting, the resistance of the oil damper 38 prevents the lifting rack body 1 from rising too quickly, so the lifting operation can be started smoothly. Next, the lifting rack body 1 is raised as shown in FIG. 10. During this lifting, the biasing force of the constant load winding spring 43 acts in the lifting direction, so the worker can raise the lifting rack body 1 with a light operating force and place the lifting rack body 1 in a specified storage position as shown in FIG. 1 and FIG. 9. Just before the lifting is completed, the lifting rack body 1 moves slowly and gently to the storage position due to the resistance of the oil damper 38, so the lifting rack body 1 can be placed in the storage position in a stable state. Furthermore, at the same time that the lifting rack body 1 is placed in the storage position, the hook 19 of the handle device 14 automatically engages with the lock piece 46 of the fixed unit 4 due to the biasing force of the biasing means (not shown).

[0050] In the rack device of this embodiment, as described below, when the lifting rack body 1 is raised or lowered, the pair of upper and lower arms 2, 3 on the left and right sides can be accurately synchronized and linked, allowing the lifting and lowering operation of the lifting rack body 1 to be performed smoothly.

[0051] That is, in the rack device of this embodiment, a pair of left and right fixed sprockets 61 connected by a connecting shaft 60 are attached to both side fixed plates 41 of the fixed unit 4, the tips of a pair of left and right chains 6 hung on the pair of fixed sprockets 61 are attached to the pair of upper arms 2, respectively, and the pair of chains 6 are kept at a constant tension regardless of the rotational position of the upper arm 2, so that the pair of chains 6 are synchronously fed and retracted in accordance with the rotational movement of one side of the upper arm 2. Therefore, when the lifting rack main body 1 is raised or lowered, the pair of left and right upper arms 2, 3 operate precisely in conjunction, allowing the lifting rack main body 1 to be raised or lowered smoothly.

[0052] In this embodiment, a movable sprocket 62 that moves up and down in the opposite direction to the lifting and lowering movement of the lifting rack main body 1 is provided behind the fixed sprocket 61, and the chain 6 is hung under the movable sprocket 62, with the rear end (base end) of the chain 6 attached to the two side fixed plates 41 via a tension coil spring 63, thereby adjusting the overall length of the chain 6 and applying a predetermined tension to the chain 6. With such a simple and flexible configuration, it is possible to impart predetermined performance to the chain 6, improving operational reliability and product quality.

[0053] Furthermore, because the rack device of this embodiment synchronizes the pair of arms 2, 3 by the forward and backward movement of the pair of chains 6 provided on both sides, there is no need to provide a synchronizing connecting rod in movable parts such as between the tips of the pair of upper arms 2 or between the tips of the pair of lower arms 3. In this way, there is no need to provide a connecting rod that moves in conjunction with the rotation of the arms, which improves design flexibility, further simplifies the structure, and improves operational reliability.

[0054] The connecting shaft 60 connecting the pair of stationary sprockets 61 is fixed in position and does not move regardless of the rotational movement of the arms 2 and 3.

[0055] Furthermore, in this embodiment, a constant load winding spring 43 is used as an upward biasing means for biasing the lifting rack main body 1 upward, so that a constant upward biasing force can always be applied to the lifting rack main body 1 regardless of the lifted or lowered position of the lifting rack main body 1, making the lifting and lowering operation of the lifting rack main body 1 even smoother.

[0056] In this embodiment, the movable sprocket 62 and the tension coil spring 63 are used to adjust the length of the chain 6 while applying a constant tension, but the present invention does not necessarily require the use of a movable sprocket and a tension coil spring. For example, in the present invention, by rotatably attaching the rear end of the chain 6 hung on the fixed sprocket 61 to the two side fixed plates 41 via a low load take-up spring, it is possible to apply a constant tension to the chain 6 regardless of the rotational movement of the upper arm 2, that is, regardless of the amount of the chain 6 that is fed out (retracted back).

[0057] In addition, in the above embodiment, the tip side of the chain 6 is attached to the upper arm 2, but this is not limited to this, and in the present invention, the tip side of the chain (cord-like body) may also be attached to the lower arm. [Explanation of symbols]

[0058] 1: Lifting rack body 2: Upper arm 21: Proximal shaft support 22: Tip side swinging part 3: Lower arm 31: Proximal shaft support 32: Tip side swinging part 35: Guide piece 41: Both side fixing plates 43: Constant load winding spring (upward biasing means) 5: Lifting link mechanism 6: Chain (cord) 60: Connecting shaft (connects sprockets) 61: Fixed sprocket (fixed rotating disk) 62: Movable sprocket (movable turntable) 63: tension coil spring (tension biasing means) 9: Fixed rack

Claims

1. A lift-and-lower rack comprising a lift-and-lower rack body and a lift-and-lower link mechanism supporting the lift-and-lower rack body so as to be freely raised and lowered relative to a fixed rack, the lift-and-lower link mechanism including fixed plates fixed to both sides of an upper portion of the fixed rack, a pair of upper arms on the left and right, and a pair of lower arms on the left and right, the base ends of the upper and lower arms being rotatably attached to the fixed plates on the left and right, respectively, and the tip ends of the upper and lower arms being rotatably attached to both sides of the lift-and-lower rack body, respectively, such that the upper and lower arms rotate upward to position the lift-and-lower rack body in a stored position above the fixed rack, and the upper and lower arms rotate downward to position the lift-and-lower rack body in a pulled-out position in front of the fixed rack, A pair of left and right stationary rotating disks are rotatably attached to the rear of the pair of upper arms of the both side fixing plates, A pair of stationary rotating disks are connected by a connecting shaft and configured to rotate in conjunction with each other, The tip ends of a pair of cord-like bodies, which are hung on the upper sides of the pair of stationary rotating plates, are attached to the tip ends of either of the upper and lower arms, and the base ends of the cord-like bodies are attached to the two side fixing plates, A lift rack characterized in that a pair of cord-like bodies are each provided with a tension adjustment means for applying a predetermined tension to the pair of cord-like bodies regardless of the rotational positions of the upper and lower arms.

2. the tension adjusting means includes a tension biasing means that is provided between the base end side of the cord-like body and the two side fixed plates and tensions the cord-like body toward the base end side, and a movable rotating disk that is attached to the two side fixed plates between the fixed rotating disk and the tension biasing means so as to be movable in the vertical direction, and has the cord-like body hung on its underside; The lift rack of claim 1, wherein the length of the cord-like body on the tip side of the fixed turntable and the length on the base side are complementarily changed by raising and lowering the movable turntable in the opposite direction to the raising and lowering movement of the lift rack body, thereby keeping the overall length constant.

3. 3. The lift rack according to claim 2, wherein the fixed rotating platen and the movable rotating platen are formed by sprockets, and the cord-like body is formed by a chain.

4. An upward biasing means is provided for biasing the lifting rack body upward during lifting and lowering operation, 4. The lifting rack according to claim 1, wherein the upward biasing means is constituted by a constant load winding spring which has a constant winding tension regardless of the amount of pulling out.

5. The pair of lower arms are disposed inside the pair of upper arms, A lift rack as described in any one of claims 1 to 3, wherein guide pieces provided on a pair of lower arms are arranged along the inner surfaces of a pair of upper arms, thereby preventing left-right positional shifting of the pair of upper arms relative to the pair of lower arms.

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