Article lifting device

Abstract

To realize an article lifting device having high durability.SOLUTION: An article lifting device includes a holding member for holding an article such as a container and a screw shaft in the vertical direction for screwing and supporting the holding member, and raises and lowers the holding member by rotation of the screw shaft. The screw shaft is suspended and supported by an upper bearing part bearing an upper part of the screw shaft. The upper part of the screw shaft is allowed to rotate around an axial center of the screw shaft and born by the upper bearing part, which regulates the movement in an axial center direction of the screw shaft. A lower part of the screw shaft is allowed to rotate around the axial center of the screw shaft and born by a lower bearing part which also allows the movement in the axial center direction of the screw shaft. Specifically, a thrust bearing receiving a load in the vertical direction transmitted from the screw shaft is also included in the upper bearing part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an apparatus for lifting and lowering an article. [Background technology]

[0002] 2. Description of the Related Art In various industrial fields, devices that reduce the labor required for the process of lifting and lowering articles are used. For example, in food processing factories, there is a process in which food raw materials are lifted and fed into processing equipment, and in order to reduce the labor required for this process, a device is installed that holds containers containing the raw materials, lifts the containers, inverts them, and feeds them into the processing equipment. As such an article lifting device, Patent Document 1 discloses a device that includes a holding member for holding a container and a vertical screw shaft that screw-supports the holding member, lifts the holding member by rotating the screw shaft, and inverts the container at the raised end. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6719712 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned Patent Document 1 does not disclose a bearing structure for the screw shaft that threadably supports the holding member in the article lifting device. Generally, in order to support a screw shaft in the vertical direction, first, the upper and lower ends of the screw shaft are supported by radial bearings. When an object is lifted, the weight of the object and the weight of the screw shaft itself cause a downward load to be transmitted from the screw shaft to the radial bearing on the lower end side. Therefore, it is necessary to add a thrust bearing to the lower end of the screw shaft to support this downward load and prevent damage to the radial bearing.

[0005] On the other hand, if a mechanism is provided for inverting the article at its raised end, when the article is inverted, the impact load due to its weight acts in the direction of pulling up the screw shaft, and the upward load is transmitted from the screw shaft to the radial bearing on the upper end side. For this reason, it is necessary to add a thrust bearing to the upper end of the screw shaft to support this upward load and prevent damage to the radial bearing. This results in the thrust bearings being distributed at both the upper and lower ends of the screw shaft.

[0006] Meanwhile, for example, in the above-mentioned food processing factory, for sanitary reasons, each device is washed especially after each operation, which creates an environment in which water is likely to accumulate on the floor. This causes water to easily seep into the area around the lower end of the screw shaft, which deteriorates the lubrication of the thrust bearing at the lower end of the screw shaft, causing early wear and reducing durability. An object of the present invention is to provide an article lifting device with high durability. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides the following technical solutions. In other words, the invention described in claim 1 is an article lifting device comprising a holding member (4) for holding an article such as a container, and a vertical screw shaft (16) that screw-engages and supports the holding member (4), and the holding member (4) is raised and lowered by rotating the screw shaft (16), characterized in that the screw shaft (16) is suspended and supported by an upper bearing portion (19) that supports the upper portion of the screw shaft (16).

[0008] The invention described in claim 2 is an article lifting device described in claim 1, in which the upper part of the screw shaft (16) is supported by an upper bearing portion (19) that allows rotation about the axis of the screw shaft (16) and restricts movement of the screw shaft (16) in the axial direction, and the lower part of the screw shaft (16) is supported by a lower bearing portion (44) that allows rotation about the axis of the screw shaft (16) and also allows movement of the screw shaft (16) in the axial direction.

[0009] The invention described in claim 3 is an article lifting device as described in claim 2, which is provided with a reversing means (92, 93) for reversing the holding member (4) at its raised end, and is configured so that upward movement of the screw shaft (16) that may occur when the holding member (4) is reversed is permitted by the lower bearing portion (44).

[0010] The invention described in claim 4 is an article lifting device as described in claim 3, in which the holding member (4) is attached to a screw member (65) screwed onto the screw shaft (16) so as to be freely rotatable up and down around a fulcrum (79), and this holding member (4) maintains a substantially horizontal posture during its ascending process, and when it reaches the end of its ascent, rotates upward around the fulcrum (79) to pass over the fulcrum and maintain the inverted state.

[0011] The invention described in claim 5 is an article lifting device comprising a holding member (4) for holding an article such as a container, and a vertical screw shaft (16) that screw-engages and supports the holding member (4), and the holding member (4) is raised and lowered by rotating the screw shaft (16), characterized in that an upper portion of the screw shaft (16) is suspended and supported by an upper bearing portion (19) that receives the vertical load transmitted from the screw shaft (16).

[0012] The invention recited in claim 6 is the article lifting device recited in claim 5, wherein the upper bearing portion (19) is provided with thrust bearings (23A, 23B) for receiving a vertical load transmitted from the screw shaft (16).

[0013] The invention described in claim 7 is an article lifting device described in claim 6, wherein the thrust bearings (23A, 23B) are formed from a first thrust bearing (23A) that receives a downward load transmitted from the screw shaft (16) and a second thrust bearing (23B) that receives an upward load transmitted from the screw shaft (16).

[0014] The invention described in claim 8 is an article lifting device as described in claim 7, which is provided with a reversing means (92, 93) for reversing the holding member (4) at its ascending end, and is configured so that a downward load generated when the holding member (4) ascends is borne by the first thrust bearing (23A), and an upward impact load generated when the holding member (4) reverses at its ascending end is borne by the second thrust bearing (23B).

[0015] The invention described in claim 9 is an article lifting device described in any one of claims 5 to 8, in which the holding member (4) is attached to a screw member (65) screwed onto the screw shaft (16) so as to be freely rotatable up and down around a fulcrum (79), and this holding member (4) maintains a substantially horizontal posture during its ascending process, and when it reaches the ascending end, rotates upward around the fulcrum (79) to pass over the fulcrum and maintain the inverted state.

[0016] The invention described in claim 10 is an article lifting device as described in either claim 5 or claim 9, which has a lower bearing portion (44) that supports the lower part of the screw shaft (16), and this lower bearing portion (44) is equipped with a radial bearing (48) that supports only the load perpendicular to the screw shaft (16), and the lower part of the screw shaft (16) is loosely fitted into this radial bearing (48) so as to be freely slidable in the axial direction. Effect of the Invention

[0017] According to the invention described in claim 1, by supporting the upper part of the screw shaft (16) that screws into the retaining member (4) by suspending it with the upper bearing portion (19), there is no need to provide a thrust bearing or the like at the lower part of the screw shaft (16). Even if water or the like penetrates around the lower part of the screw shaft (16), the screw shaft is less susceptible to the effects of water, etc., and durability is improved.

[0018] According to the invention recited in claim 2, in addition to achieving the effects of the invention recited in claim 1, the lower bearing portion (44) allows the screw shaft (16) to move in the axial direction, making it possible to reduce the occurrence of malfunctions or breakage due to vertical movement or vibration of the screw shaft (16) caused by load fluctuations, etc.

[0019] According to the invention recited in claim 3, in order to achieve the effect of the invention recited in claim 2, the upward movement of the screw shaft (16) that may occur when the holding member (4) is reversed is permitted, thereby reducing failure or damage due to impact, etc., when the holding member (4) is reversed.

[0020] According to the invention recited in claim 4, in addition to achieving the effects of the invention recited in claim 3, it is possible to make it difficult for malfunctions or breakages to occur due to the impact load when the holding member (4) exceeds the fulcrum and reverses.

[0021] According to the invention described in claim 5, the upper part of the screw shaft (16) that screw-supports the retaining member (4) is suspended by the upper bearing portion (19) that receives the vertical load transmitted from the screw shaft (16). This eliminates the need to provide a thrust bearing or the like at the lower part of the screw shaft (16). Even if water or the like penetrates around the lower part of the screw shaft (16), the screw shaft (16) is less susceptible to the effects of the water, etc., and its durability is improved.

[0022] According to the invention recited in claim 6, in order to achieve the effect of the invention recited in claim 5, the vertical load transmitted from the screw shaft (16) is supported by the thrust bearings (23A, 23B) provided in the upper bearing portion (19), thereby eliminating the need to provide a thrust bearing or the like at the lower part of the screw shaft (16).

[0023] According to the invention recited in claim 7, in addition to achieving the effects of the invention recited in claim 6, the first thrust bearing (23A) and the second thrust bearing (23B) arranged in a concentrated manner at the upper part of the screw shaft (16) can bear the downward and upward loads transmitted from the screw shaft (16), thereby improving durability.

[0024] According to the invention recited in claim 8, in order to achieve the effects of the invention recited in claim 7, the downward load generated when the holding member (4) rises is borne by the first thrust bearing (23A), and the impact load generated when the holding member (4) passes over the fulcrum and reverses is borne by the second thrust bearing (23B), thereby making it possible to reduce the occurrence of malfunction or damage.

[0025] According to the invention recited in claim 9, in addition to the effects of the invention recited in any one of claims 5 to 8, it is possible to make it less likely that a malfunction or breakage will occur due to an impact load when the holding member (4) passes over the fulcrum and reverses.

[0026] According to the invention recited in claim 10, in order to achieve the effects of the invention recited in any one of claims 5 to 9, the lower part of the screw shaft (16) is loosely fitted in the radial bearing (48) so as to be freely slidable in the axial direction, so that the screw shaft (16) is less likely to malfunction or break due to vertical movement or vibration caused by load fluctuations, etc. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a left side view of a lifter which is an article lifting device. [Diagram 2] FIG. [Diagram 3] 4 is a partially cutaway plan view showing the lifting drive unit of the lifter. FIG. [Figure 4] FIG. 4 is an explanatory side view showing the periphery of the upper end portion of the screw shaft in section. [Diagram 5] 5 is a partially cutaway plan view of the bearing portion shown in FIG. 4 for illustrating the same; FIG. [Figure 6] FIG. 4 is an explanatory side view showing the periphery of the lower end portion of the screw shaft in section. [Figure 7] 7 is a partially cutaway plan view of the bearing portion in FIG. 6 for illustrating the same. FIG. [Figure 8] FIG. 4 is an explanatory diagram of a drive mechanism for a screw shaft. [Figure 9] 5 is a side cross-sectional view partially illustrating a state in which a holding member is screwed onto a screw shaft. FIG. [Figure 10] FIG. 4 is a side view for explaining the reversing means. [Figure 11] FIG. 4 is a rear view for explaining the reversing means. [Figure 12] FIG. 4 is a front view for explaining a portion in a state where a container is held. [Figure 13] FIG. 13 is a left side view showing a state in which a container is introduced into the holding member. [Figure 14] 13 is a right side view showing a state in which a container is introduced into the holding member. FIG. [Figure 15] FIG. 4 is a front view showing a state in which a container is introduced into a holding member. [Figure 16] FIG. 13 is a plan view showing a state in which the dolly is introduced into the holding member (containers are omitted). [Figure 17] 13 is a left side view of a main part at the initial stage of container insertion into the holding member. FIG. [Figure 18] FIG. 18 is a plan view of FIG. [Figure 19] 13 is a left side view of the main parts when the container has been completely inserted into the holding member. FIG. [Figure 20] FIG. 20 is a plan view of FIG. [Figure 21] 13 is a right side view showing a state in which a container is introduced into the holding member. FIG. [Figure 22] FIG. 4 is a plan view showing a state in which a container is introduced into a holding member. [Diagram 23] FIG. 23 is an enlarged view of a portion of FIG. 22. [Figure 24] FIG. 24 is an enlarged view of a portion of FIG. 23. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In the embodiment for carrying out the present invention, a lifter used in a meat processing plant will be described in detail below as an example of an article lifting device. In addition, based on the direction in which items are introduced into this lifter, the upstream side of the introduction direction is defined as the "front side" and the downstream side of the introduction direction is defined as the "rear side", and the left side when facing downstream in the introduction direction is defined as the "left side" and the right side is defined as the "right side".

[0029] (Basic structure of the lifter) As shown in Figures 1 and 2, the lifter (the "article lifting device" of the present invention) 1, which is a transport device, is configured by erecting a vertical support frame 3 on the right side of a machine base frame 2 formed by framing pipe material, and by providing a lift arm (the "holding member" in the claims) 4 that is supported by this support frame 3 and moves up and down.

[0030] (Machine frame) As shown in Figs. 1 and 2, the machine base frame 2 is integrally formed by connecting left and right side frames 5 in the front-rear direction with a left-right frame 6. The left and right side frames 5 are each provided at their front and rear ends with a freely rotatable roller 7 for movement and an adjustment bolt type stopper 8 for lifting the roller 7 above the ground. The front ends of the left and right side frames 5 are curved so as to bulge upward, and the front rollers 7 are disposed in the spaces below these curved portions.

[0031] Vertical frames 9 are erected from the front and rear ends of the left and right side frames 5, and the upper ends of these four vertical frames 9 are connected by a horizontal frame 10 to form a surrounding frame 11. The vertical frame 9 on the front right side is extended upward and supports a switch box 12 at its upper end. Behind the switch box 12, a control box 12A is disposed. This surrounding frame 11 surrounds the lower periphery of the support frame 3.

[0032] (Support frame) As shown in Figures 1, 2 and 7, a plate body 13 is welded and fixed across the right end of the left-right frame 6 of the machine base frame 2 and the right side frame 5, and the lower end of the support frame 3 is fixed to the upper surface of this plate body 13.

[0033] As shown in FIG. 3, the support frame 3 is formed by bending a wide steel plate (or stainless steel plate) into a U-shape in plan cross section. An opening 14 is formed on the left side surface of the support frame 3, and a cover plate 15 covering the left side of the opening 14 is placed at a position offset to the left from the opening 14, and the front end of the cover plate 15 is fixed to the support frame 3 side.

[0034] (Lifting mechanism) As shown in Figures 3 to 7, a vertical screw shaft 16 is rotatably disposed in the center inside the support frame 3, and an electric motor 17 that rotates this screw shaft 16 is disposed on the upper right side of the support frame 3.

[0035] (Upper bearing part) As shown in Figures 4 and 5, a horizontal support plate 18 is fixed to the upper end of the support frame 3, and an upper bearing portion 19 is fitted from above into a through hole formed in this support plate 18. That is, the upper bearing portion 19 has an outer diameter that varies in three steps in the vertical direction, and has a through hole in the center that extends in the vertical direction.

[0036] The medium diameter portion 21 formed in the vertical middle portion of this upper bearing portion 19 is fitted into a through hole in the support plate 18, and the lower surface of the uppermost large diameter portion 20 is placed on the upper surface of the support plate 18 and fixed in place. Two grooves, one above the other, are formed on the inner circumference of the small diameter portion 22 at the bottom of this upper bearing portion 19, and the first thrust bearing 23A, which receives a downward load, is fitted and installed in the upper groove, and the second thrust bearing 23B, which receives an upward load, is fitted and installed in the lower groove. A radial bearing 24 is fitted into the inner periphery of the upper bearing portion 19 from the small diameter portion 22 to the medium diameter portion 21, and the upper surface of this radial bearing 24 is fixed in position by a C-shaped retaining ring 25.

[0037] A shallow, saucer-shaped lower cover member 27 is fitted into an annular protrusion 26 that protrudes downward from the underside of the small diameter portion 22 of the upper bearing portion 19, and this lower cover member 27 is fastened and fixed to the small diameter portion 22 with bolts 28. As a result, the underside of the small diameter portion 22 is covered with the lower cover member 27. A through hole is formed in the center of this lower cover member 27, and an annular seal member 29 is supported on a step formed on the inner surface of this through hole, with its outer surface in contact with a portion of its underside. As a result, with the lower cover member 27 fastened and fixed to the small diameter portion 22, the upper surface of the seal member 29 abuts against the lower surface of the protruding portion 26 and is held there.

[0038] The inner circumferential surface of the uppermost large diameter portion 20 is formed to have a larger diameter than the inner circumferential surface of the medium diameter portion 21, forming a step portion between the inner circumferential surfaces of the large diameter portion 20 and the medium diameter portion 21. A space is formed in the small diameter portion 22 below the radial bearing 24, and a lubricant pressure-injection passage 33 that connects this space to the outside of the small diameter portion 22 is drilled obliquely downward, and a plug member 34 is attached by screwing it into the outer end of this lubricant pressure-injection passage 33.

[0039] Thus, the portion of the upper part of the screw shaft 16 above the screw portion is reduced in diameter in two stages, and an annular spacer 35 is fitted into the first stage small diameter portion 16A adjacent to the screw portion and positioned by the step portion formed between the screw portion and the small diameter portion 16A. In this state, the upper end of the screw shaft 16 is inserted from below into a through hole formed in the upper bearing portion 19 .

[0040] As a result, first-stage small diameter portion 16A is fitted into and supported by radial bearing 24, first thrust bearing 23A, and second thrust bearing 23B, and the upper surface of spacer 35 abuts against and supports the lower surface of second thrust bearing 23B. That is, small diameter portion 16A is fitted and fixed to the inner circumferential surface of radial bearing 24, fitted and fixed to the inner circumferential surface of the upper plate of first thrust bearing 23A, and fitted and fixed to the inner circumferential surface of the lower plate of second thrust bearing 23B.

[0041] On the other hand, the outer peripheral surface of the radial bearing 24 is fitted and fixed to the inner peripheral surface of the medium diameter section 21, and the lower plate of the first thrust bearing 23A is fitted and fixed in a state of contacting the upper surface of a protrusion 38 formed between the above-mentioned upper and lower two stages of grooves. As a result, the downward load applied to the first thrust bearing 23A is supported by the upper surface of this protrusion 38. Also, the upper plate of the second thrust bearing 23B is fitted and fixed in a state of contact with the lower surface side of the protrusion 38. As a result, the upward load applied to the second thrust bearing 23B is supported by the lower surface of the protrusion 38.

[0042] Additionally, the outer peripheral surface of the spacer 35 abuts against the inner peripheral surface of the seal member 29 .

[0043] Then, two spacers 36, 37 of different thicknesses are fitted into the upper end of the screw shaft 16, with the lower, thinner spacer 36 fitted into the outer periphery of the first-stage small diameter portion 16A of the screw shaft 16, and the upper, thicker spacer 37 fitted into the outer periphery of the second-stage small diameter portion 16B of the screw shaft 16.

[0044] Then, the upper cover member 30 is fitted onto the inner peripheral surface of the large diameter portion 20 from above, and the upper cover member 30 is fastened and fixed to the large diameter portion 20 with a bolt 31 . A through hole is formed in the center of this upper cover member 30, and a step is formed on the inner peripheral surface of this through hole to support an annular seal member 32 with its outer peripheral surface in contact with a part of its lower surface. As a result, the inner peripheral surface of the seal member 32 abuts against the outer peripheral surface of the upper spacer 37.

[0045] Further, a driven sprocket 39 is fitted onto the second stage small diameter portion 16B of the screw shaft 16, and a key 40 restricts the relative rotation with respect to the screw shaft 16. A collar 41 is fitted onto the upper surface side of the driven sprocket 39 in the small diameter portion 16B, and a double nut 43 is screwed onto a threaded portion 42 formed on the upper end of the small diameter portion 16B for fastening.

[0046] As a result of the above, the upper end (upper portion) of the screw shaft 16 is supported so as to be rotatable only.

[0047] (Lower bearing part) As shown in FIGS. 6 and 7, a lower bearing portion 44 is fastened and fixed to the upper surface of the plate body 13 by means of a bolt 45. The lower bearing portion 44 is mainly formed of a cylindrical member 46 having a bottom surface. A C-shaped retaining ring 47 is fitted into a groove formed on the inner peripheral surface of the lower part of the cylindrical member 46 , and the lower radial bearing 48 is fitted onto the upper side of the C-shaped retaining ring 47 . The radial bearing 48 is positioned by the upper surface of the C-shaped retaining ring 47 .

[0048] A cover member 49 having a through hole through which the lower end of the screw shaft 16 is inserted is fitted onto the upper surface of the cylindrical member 46 and fixed thereto. A step is formed on the inner peripheral surface of the through hole in the cover member 49, and the outer peripheral surface and part of the lower surface of the seal member 50 are positioned by this step.

[0049] Furthermore, a space is formed below the radial bearing 48 inside the cylindrical member 46, and a passage 51 is drilled obliquely upward to connect this space to the outside of the cylindrical member 46. A plug member 52 is attached by screwing it to the outer end of this passage 51. However, the provision of this passage 51 and plug member 52 is not essential. Furthermore, a plurality of through holes 53 for discharging water and the like are formed in the bottom surface of the cylindrical member 46 and are connected to the through holes 54 formed in the plate body 13 .

[0050] On the other hand, the diameter of the lower end of the screw shaft 16 is reduced in three stages, and a plate member 55 having a circular shape as viewed in the axial direction is fastened and fixed to the outer circumferential surface of the first stage reduced diameter portion 16C by a clamping member 56 and a screw 57. The second stage small diameter portion 16D at the lower end of the screw shaft 16 is fitted into the inner periphery of the radial bearing 48 so as to be vertically movable (axially movable) and supports only rotation of the screw shaft 16 about its axis. In this state, the outer circumferential surface of the first stage small diameter portion 16C of the screw shaft rotatably contacts the inner circumferential surface of the sealing member 50 described above.

[0051] Further, the third stage small diameter portion 16E at the bottom end of the screw shaft 16 is located in the space below the radial bearing in the cylindrical member . Furthermore, a predetermined gap is formed between the lower surface of the plate member 55 and the upper surface of the cover member 49 of the lower bearing portion 44 described above.

[0052] As a result of the above, the lower end (lower portion) of the screw shaft 16 is supported so as to be rotatable and movable in the vertical direction (movable in the axial direction). As a result, the radial bearing 48 performs a centering function for the rotation of the screw shaft 16 about its axis without transmitting substantially any load in the vertical direction from the screw shaft 16 . With this configuration, the screw shaft 16 is supported in a suspended state by the upper bearing portion 19 ("suspended support" in the claims).

[0053] (Transmission) As shown in Figures 4 and 8, an electric motor 17 is supported on a support plate 18 fixed to the upper end of the support frame 3, and a transmission chain 60 is wound between a driving sprocket 59 attached to the output shaft 58 of this electric motor 17 and a driven sprocket 39 attached to the upper end of the above-mentioned screw shaft 16. In addition, since the electric motor 17 rotates forward and backward to raise and lower the article, tension mechanisms that absorb the slack in the transmission chain 60 that occurs at this time are provided on both sides of the range in which the transmission chain 60 is tensioned.

[0054] That is, tension sprockets 62, 62 supported movably by two tension arms 61, 61 are disposed at an intermediate position between the drive sprocket 59 and the driven sprocket 39. Each tension sprocket 62, 62 is brought into contact with the parallel locus portion of the transmission chain 60 from the outside, and the tension sprockets 62, 62 are linked together by a tension rod 64 via a tension spring 63 that biases the tension sprockets 62, 62 in directions approaching each other.

[0055] (operating device) On the front surface of the above-mentioned switch box 12, an up operation switch 12U is provided at the top, a down operation switch 12D is provided at the bottom, a stop operation switch 12S is provided in the middle between the top and bottom, and an emergency stop switch 12K is provided to the right of the down operation switch 12D. By pressing the up operation switch 12U, the electric motor 17 is driven in the forward direction to raise the lift arm 4, and by pressing the down operation switch 12D, the electric motor 17 is driven in the reverse direction to lower the lift arm 4.

[0056] When the stop operation switch 12S is pressed while the lift arm 4 is rising or falling, the rotational drive of the electric motor 17 is stopped at this point, and the lift arm 4 maintains its position. Furthermore, when the emergency stop switch 12K is pressed while the lift arm is rising or falling or while the lift arm is stopped, the emergency stop switch 12K is locked (mechanically held) in the pressed-in state (ON state).

[0057] In this state, even if the up operation switch 12U and the down operation switch 12D are operated, the electric motor 17 is not driven to rotate, and the lift arm 4 does not move up or down. The emergency stop switch 12K in the pressed-in state can be unlocked by rotating it.

[0058] These sequence controls are performed by a control circuit in the control box 12A.

[0059] (Screw joint between screw shaft and lift arm) As shown in FIG. 3, inside the support frame 3, a screw member 65 having a rectangular box shape in a plan view, surrounded on all four sides by plates 71, is provided by screwing onto the screw shaft 16. Resin movable sliding members 66 are attached to both left and right sides of the front surface and both left and right sides of the rear surface of the screw-fitting member 65 .

[0060] Meanwhile, fixed side sliding guide members 67 made of resin and formed long in the vertical direction are attached to both front and rear sides of the inner surface of the support frame 3 . The screw member 65 is slidably guided in the vertical direction (lifting direction) by the sliding contact between the movable sliding member 66 and the fixed sliding guide member 67 .

[0061] As shown partially diagrammatically in FIG. 9, in the screw-engagement member 65, plates 72, 72 that connect the opposing plates 71, 71 are provided, and a right end portion of a connecting member 68 is connected to the plate 72 on one side. As a result, the connecting member 68 protrudes to the left side from the opening 14 described above.

[0062] The screw shaft 16 is inserted into the vertical space surrounded by the opposing plates 71, 71 and plates 72, 72, and a cylindrical female screw member 74 which is prevented from rotating by a pin 73 on the plate 72 side is screwed onto the screw shaft 16. The female screw member 74 has a female screw formed on its inner peripheral surface, which is screwed into the threaded portion of the screw shaft 16 . The upper end surface of this female screw member 74 abuts against the lower surface of a reinforcing member 75 which connects the upper ends of the opposing plate bodies 71, 71 together.

[0063] Furthermore, a female screw member 76 for preventing falling is screwed into a portion of the screw shaft 16 that is a predetermined distance below the female screw member 74 . The female screw member 76 for preventing falling is prevented from rotating by abutting against the plates 71, 72, and has a truncated cone-shaped projection 77 extending upward from its upper end.

[0064] In the event that slippage occurs in the screw-threaded state between the female screw member 74 and the screw shaft 16, this protrusion 77 fits into a downward annular groove 78 formed in the lower end of the female screw member 74, preventing the screw-threaded member 65 from falling off.

[0065] (Lift arm) As shown in Figures 3 and 12, the upper end of a vertical support plate 70 is fixed to the rear end of the vertical wall portion of the connecting member 68, and the right end of a left-right support shaft (the "fulcrum" in the claims) 79 is inserted into a through hole formed in the lower end of the support plate 70 and fixed. An adjustment bolt 81 is attached to the upper end of the support plate 70 via a stay 80 .

[0066] Thus, the lift arm (referred to as the "holding member" in the claims) 4 is rotatably supported on the support shaft 79 supported in a cantilever state as described above. This lift arm 4 is composed of an axle tube 82 that is loosely fitted onto the support axle 79 so as to be able to rotate freely, an upper arm 83 that has its base welded to the right end of the axle tube 82 and is extended upward, and left and right support arms 84 that have their bases welded to the middle and left end of the axle tube 82 and are extended forward. The left and right support arms 84 have their portions forward of their middle portions formed into a plate shape with their width direction facing the up-down direction.

[0067] By inserting this plate-like portion into the internal space of holders 86 attached to both the left and right sides of the container 85, the container 85 is supported by left and right support arms 84. The top of the container 85 is open, and the container 85 is placed on a cart 89 equipped with casters 87 and a handle 88 .

[0068] (Lift arm reversal mechanism) A block 90 fixed to the upper arm 83 comes into contact with the above-mentioned adjustment bolt 81, thereby restricting the rotational position of the lift arm 4 with the support shaft 79 as a fulcrum. As shown in FIG. 3, a left-right support pin 91 is inserted and fixed into a through hole formed in the upper end of upper arm 83, and a guide roller 92 is rotatably supported on the right-side extending end of this support pin 91.

[0069] On the other hand, as shown in Figs. 1, 10 and 11, a guide rail 93 having a U-shaped cross section bent into an inverted L shape is provided on the upper rear surface of the support frame 3. As shown in FIG. 10, this guide rail 93 is fixed to the left side of a reinforcing plate 95 that protrudes rearward from a vertical plate-like base 94 with its left side open. At the lower end of the guide rail 93, an expanded guide portion 96 is formed.

[0070] The base 94 has bolt holes at its upper and lower ends, while a backing plate 97 fixed to the upper rear surface of the support frame 3 has a large number of screw holes 98 formed therein. As shown in Figure 11, the numerous screw holes 98 are arranged at predetermined intervals in the vertical direction, and the guide rail 93 is attached to the support frame 3 by inserting and screwing bolts 99 into the bolt insertion holes and screw holes 98 formed in the base 94 and fastening them together. The height of the guide rail 93 can be adjusted by selecting the screw hole 98 into which the bolt 99 is screwed.

[0071] As shown in FIG. 1, the electric motor 17 is driven in the normal direction, and the screw shaft 16 rotates to raise the support shaft 79 together with the screw member 65, and the container 85 supported by the left and right support arms 84 is raised. Then, the guide roller 92 journaled on the upper end of the upper arm 83 enters the guide rail 93 from the guide portion 96, passes through the bent portion of the guide rail 93, reaches the horizontal portion, and is guided rearward.

[0072] As the support shaft 79 rises, the upper arm 83 rotates rearward and downward around the axis of the support shaft 79, causing the left and right support arms 84 to rotate upward, and the tips of the left and right support arms 84 move rearward beyond the support shaft (fulcrum) 79. As a result, as shown by the two-dot chain lines in FIGS. 1 and 2, the container 85 moves backward invertedly, and the contents therein are discharged.

[0073] The above-mentioned configuration in which the guide rollers 92 are guided by the guide rails 93 and the left and right support arms 84 pass over the fulcrums is referred to as the "reversing means" in the claims.

[0074] (Upper limit detector and overrun detector) Furthermore, the lower end of a support plate 100 that is L-shaped in plan view is fixed to the upper part of the base 94, and a stay 101 is fastened and fixed to the upper part of this support plate 100. The stay 101 is formed in an inverted U-shape when viewed from the side, and an upper limit detection switch 102 and an overrun detection switch 103 are attached to the stay 101.

[0075] The upper and lower L-shaped plates (not shown) attached to the above-mentioned support plate 100 are positioned so as to abut against the upper limit detection swing arm 104 on the upper limit detection switch 102 side and the overrun detection swing arm 105 on the overrun detection switch 103 side, respectively.

[0076] (Intermediate stop position detection unit) As shown in Figures 3 and 12, the rear end of a plate body 106 that is bent into an L shape when viewed from above is connected to the above-mentioned support plate 100, and a grease sealing tube 108 and a stay 109 that is U-shaped when viewed from above are attached to a front wall portion 107 of this plate body 106. A detection target plate 110 made of iron or stainless steel and bent into an L shape in a plan view is fastened and fixed to the front surface of the stay 109 with a bolt 111 . As a result, the support shaft 79 supporting the lift arm 4 and the detection plate 110 move up and down integrally.

[0077] As shown in Figs. 2 and 12, a frame 112 fixed to the front wall of the support frame 3 has a slit 113 having a predetermined length in the vertical direction formed in the vertical middle part of the front wall. A stay 114 is placed on this slit 113, and a bolt 115 is inserted through a bolt insertion hole formed in this stay 114 and through the slit 113, and then screwed into a nut on the inside of the support frame 3 to fasten and fix the bolt in place. An electromagnetic proximity sensor 116 that detects the approach of the detection target plate 110 is fixed to the stay 114 .

[0078] As a result, by loosening the fastening by the bolt 115, the proximity sensor 116 can be slid vertically along the slit 113, thereby adjusting the height.

[0079] (Operation description) When the left and right support arms 84 are inserted into the left and right holders 86 of the container 85 and the switch on the up-side of the switch box 12 is operated, the electric motor 17 is driven, and the screw shaft 16 rotates, causing the screw member 65 and the left and right lift arms 4 to rise together. During this ascent process, if the proximity sensor 116 detects the approach of the detection plate 110, the current supply to the electric motor 17 is cut off after the timer has elapsed from the time of detection, the ascent of the container 85 automatically stops, and the container 85 waits in this intermediate stop position. As a result, when the worker checks the state of the contents inside the container 85 and then operates the lift switch again, the left and right lift arms 4 start to rise again.

[0080] As a result of this rise, the guide roller 92 attached to the upper arm 83 enters through the guide portion 96 of the guide rail 93 and is guided rearward, causing the left and right lift arms 4 to rotate upward around the support shaft 79, and the container 85 assumes an inverted position. This causes the contents to be discharged from the container 85.

[0081] When the container 85 is inverted in this manner, the upper and lower L-shaped plates attached to the support plate 100 described above come into contact with the upper limit detection swing arm 104 on the upper limit detection switch 102 side, and the current supply to the electric motor 17 is automatically cut off. In addition, if the current supply to the electric motor 17 is not cut off due to a malfunction or breakage of the upper limit detection switch 102, the upper and lower L-shaped plates attached to the support plate 100 abut against the overrun detection swing arm 105 on the overrun detection switch 103 side, automatically cutting off the current supply to the electric motor 17. That is, the overrun detection switch 103 functions as a safety device.

[0082] (Safety device to prevent containers from falling) The above-mentioned container 85, the dolly 89 supporting it, and the lift arm 4 may be configured as shown in FIGS.

[0083] That is, the left and right support arms 84 are formed as plate members formed with a wide width in the vertical direction, and a long slit 120 is formed along the front-rear direction in the vertical middle of the left and right support arms 84 . The slit 120 has an open front end portion to form an introduction portion 121, and a downwardly recessed portion 122 at its rear end portion. When the left and right support arms 84 are raised by the forward drive of the electric motor 17, this recess 122 acts as an engagement portion that prevents the container 85 from sliding forward by fitting a pin 133 on the container 85 side described later.

[0084] Further, left and right holders 123 are fastened and fixed to the outer surfaces of the left and right support arms 84 at locations rearward of the rear ends of the slits 120 . Two sliding rods 124 are supported slidably through the holder 123 at two positions, top and bottom, along the length of the slit 120 . A contact plate 125 bent in a V-shape when viewed from the side is attached to the front ends of the two sliding rods 124, and a compression spring 126 for returning to the origin is provided between this contact plate 125 and the front surface of the holder 123.

[0085] Left and right support frames 127 are extended forward from two locations on the left and right frame 6 of the machine base frame 2 of the lifter 1. Then, support stays 128, which are bent into an inverted L shape when viewed from the side, are fastened and fixed onto the front ends of the left and right support frames 127 with bolts 129, and left and right switch boxes 130 are fastened and fixed to the front ends of the left and right support stays 128 with bolts 131 so that the height can be adjusted using long holes in the vertical direction. The left and right switch boxes 130 each have a built-in normally open switch (electrical contact) and are provided with contacts 132 for turning the switch ON / OFF.

[0086] On the other hand, the base of a pin 133 protruding outward to the left and right and the vertical surface portions of left and right regulating plates 134 each having an L-shaped cross section and a horizontal surface that continues horizontally from near the upper end position of the pin 133 are welded to the bottom on both the left and right sides of the container 85. The regulating plate 134 comes into contact with the upper edges of the slits 120 of the left and right support arms 84 when the container 85 is supported by the left and right support arms 84 , thereby regulating the inclination of the container 85 .

[0087] With the above-described configuration, when the container 85 is placed on the cart 89 and the cart 89 is inserted between the left and right support arms 84, the pin 133 and the regulating plate 134 on the container 85 side enter the slit 120 through the introduction portion 121 of the left and right support arms 84. Then, the left and right pins 133 reach the recesses 122 at the rear ends of the slits 120, come into contact with the contact plate 125, and push it backward.

[0088] As a result, the abutment plate 125 moves back while compressing the compression spring 126, and the lower surface of the lower part of this abutment plate 125 presses the contact 132 downward, turning on the switch in the switch box 130. A control circuit in the control box 12A is configured so that, on the condition that both of the switches in the left and right switch boxes 130 are turned on, the electric motor 17 can be driven in the forward direction by operating the lift operation switch 12U.

[0089] This eliminates the problem of the electric motor 17 rotating in the forward direction and causing the container 85 to fall off when either the left or right switch in the switch box 130 is not turned on, i.e., when either the left or right pin 133 is not positioned above the recess 122 (when the container 85 is not held in a parallel position relative to the left and right support arms 84).

[0090] In addition, the bases of leaf springs 135 that clamp the left and right sides of the carriage 89 when the carriage 89 has completely inserted between the left and right support arms 84 are fixed to the inner rear surfaces of the left and right support arms 84 . Thus, when the carriage 89 has completed its insertion between the left and right support arms 84, a force acts on the carriage 89 in the direction opposite to the insertion direction (the direction pushing the carriage 89 forward from between the left and right support arms 84) due to the extension force of the compression spring 126 described above. However, by clamping the left and right sides of the carriage 89 with the free ends of the left and right leaf springs 135, the problem of the carriage 89 departing from the appropriate position held by the left and right support arms 84 can be reduced.

[0091] As shown in FIGS. 14, 16, and 21 to 24, a stopper 136 is provided at the front end of the right support arm 84. That is, the base of a fulcrum pin 137 in the left-right direction is fixed to the outer surface of the front end portion of the right support arm 84, and the rear portion of a plate 138 is axially supported by this fulcrum pin 137 so as to be rotatable up and down. A compression spring 139 is attached to the front of the plate 138 to bias the front of the plate 138 upward.

[0092] The upper rear end of a tread pressure rotating member 141 having a tread portion 140 at its front end is fixed to the front end of the plate 138. The tread pressure portion 140 is set in a front-upward inclined position. The rear end of this tread pressure rotating member 141 is bent in an L-shape and raised, and the base of a front-rear direction restricting pin 143 is fixed to this raised portion.

[0093] The up and down rotation position of the plate 138 is regulated by the abutment between the front upper surface of the plate 138 and a left-right pin 142 fixed to the outer surface of the front end of the right support arm 84 . In addition, the upper end of a sensing plate 145 having a vertical plate surface and a lower end bent backward is fixed to the rear end of the plate 138 , and a contact 147 of a safety switch 146 is abutted against the front side of this sensing plate 145 .

[0094] When the worker steps down on the tread portion 140 to remove the lowered container 85 from the lifter 1, the plate 138 rotates downward and forward together with the tread rotation member 141, and the sensing plate 145 rotates upward and separates from the contact 147. As a result, the safety switch 146 is turned off, and the forward rotation of the electric motor 17 is prohibited.

[0095] Furthermore, as the tread pressure rotating member 141 rotates downward, the regulating pin 143 fixed to the rear end of the tread pressure rotating member 141 descends, and the regulating plate 134 on the container 85 side and the pin 133 move away from the forward extraction trajectory. This allows the container 85 to be removed forward from between the left and right support arms 84.

[0096] The above describes a lifter used in a meat processing plant, but the present invention is not limited to this and can also be applied to devices for lifting and lowering industrial raw materials. [Explanation of symbols]

[0097] 4 Lift arm (holding member) 16 Screw shaft 19 Upper bearing part 23A First thrust bearing 23B Second thrust bearing 44 Lower bearing part 48 Radial bearing 65 Screw-in member 79 Fulcrum Axis (Fulcrum) 92 Guide roller (reversal means) 93 Guide rail (reversal means)

Claims

1. An article lifting device comprising a holding member (4) for holding an article, and a vertical screw shaft (16) for screwing and supporting the holding member (4), the holding member (4) being raised and lowered by rotation of the screw shaft (16), the screw shaft (16) being suspended and supported by an upper bearing part (19) which bears an upper part of the screw shaft (16), The upper part of the screw shaft (16) is supported by an upper bearing part (19) that allows rotation of the screw shaft (16) around its axis and restricts movement of the screw shaft (16) in the axial direction, and the lower part of the screw shaft (16) is supported by a lower bearing part (44) that allows rotation of the screw shaft (16) around its axis and also allows movement of the screw shaft (16) in the axial direction, An article lifting device comprising a reversing means (92, 93) for reversing the holding member (4) at its raised end, and characterized in that the upward movement of the screw shaft (16) that may occur when the holding member (4) is reversed is permitted by the lower bearing portion (44).

2. 2. An article lifting device as described in claim 1, wherein the retaining member (4) is attached to a screw member (65) screwed onto the screw shaft (16) so as to be freely rotatable up and down about a fulcrum (79), and the retaining member (4) maintains a substantially horizontal posture during its ascent process, and when it reaches its ascent end, rotates upward about the fulcrum (79) to pass over the fulcrum, thereby maintaining the inverted state.

3. An article lifting device comprising a holding member (4) for holding an article, and a vertical screw shaft (16) for screwing and supporting the holding member (4), the holding member (4) being raised and lowered by rotation of the screw shaft (16), the upper part of the screw shaft (16) being suspended and supported by an upper bearing part (19) which receives the vertical load transmitted from the screw shaft (16), The upper bearing portion (19) is provided with thrust bearings (23A, 23B) for receiving a vertical load transmitted from the screw shaft (16), An article lifting device, characterized in that the thrust bearings (23A, 23B) are formed from a first thrust bearing (23A) that receives a downward load transmitted from the screw shaft (16) and a second thrust bearing (23B) that receives an upward load transmitted from the screw shaft (16).

4. 4. An article lifting device as described in claim 3, further comprising a reversing means (92, 93) for reversing the holding member (4) at its ascending end, wherein a downward load generated when the holding member (4) ascends is received by the first thrust bearing (23A), and an upward impact load generated when the holding member (4) reverses at its ascending end is received by the second thrust bearing (23B).

5. 5. An article lifting device as described in claim 3 or 4, wherein the retaining member (4) is attached to a screw member (65) screwed onto the screw shaft (16) so as to be freely rotatable up and down about a fulcrum (79), and the retaining member (4) maintains an approximately horizontal posture during its ascent process, and when it reaches its ascent end, rotates upward about the fulcrum (79) to pass over the fulcrum, thereby maintaining the inverted state.

6. 6. An article lifting device as claimed in any one of claims 3 to 5, further comprising a lower bearing portion (44) for supporting the lower portion of the screw shaft (16), a radial bearing (48) for supporting only loads perpendicular to the screw shaft (16) in the lower bearing portion (44), and the lower portion of the screw shaft (16) is loosely fitted into the radial bearing (48) so as to be freely slidable in the axial direction.

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