elevator

Abstract

When a part of a power transmission mechanism is damaged, the lifting operation of a container loading mechanism is stopped, the damage of the part can be quickly found out, and a serious personal accident can be prevented. The bread dough elevator 1 has left and right upright columns 2a, 2b and a container loading mechanism 5 for loading containers between the left and right upright columns. A rotatable threaded shaft 7 is arranged in the left and right upright columns. The threaded shaft is matched with a nut 8 connected to the container loading mechanism. The container loading mechanism is lifted by rotating the threaded shaft. A support seat 27 is fixed to the side of the container loading mechanism 5. A support shaft 37 is arranged on the outer peripheral surface of a nut housing 32 mounted on the nut 8. The support shaft 37 is embedded in the central hole of the support seat 27.

Description

Technical Field

[0001] This invention relates to a hoist, and more particularly to a hoist that raises and lowers a container loading mechanism by rotating a threaded shaft. Background Technology

[0002] In the material preparation area based on the sponge dough method, a dough lifter is generally used for conveying dough to a divider or mixer (e.g., see Patent Document 1, etc.). This dough lifter includes left and right columns (main columns) and a container loading mechanism disposed between the left and right columns for loading containers. A rotatable threaded shaft (main shaft or male thread) is located within the left and right columns. A nut is connected to the container loading mechanism on the threaded shaft, and the container loading mechanism is raised and lowered by rotating the threaded shaft; this is a well-known dough lifting method. In such a dough lifter, for example, as... Figure 9 As shown, a pair of support shafts 137 are provided on the outer circumferential surface of the nut housing 132 to which the spiral nut 108 is mounted, and the pair of support shafts 137 have a U-shaped support portion in cross section. The upper end of the connecting member 152 is axially supported on the support member 151, and the lower end of the connecting member 152 is axially supported on the side of the container loading mechanism 105. In other words, the nut 108 is connected to the container loading mechanism 105 via a pair of support shafts 137, so that the container loading mechanism 105 is supported on both sides and can be smoothly raised and lowered.

[0003] Existing technical documents Patent Document 1: Japanese Patent Application Publication No. 07-75478 Summary of the Invention

[0004] The problem to be solved by the present invention However, in conventional bread dough lifting machines, nut 108 is connected to container loading mechanism 105 via a pair of support shafts 137, and the motor transmits power to the threaded shafts 107 inside the left and right columns via a transmission mechanism. When components of the power transmission mechanism (such as tire couplings, reducers, etc.) fail, the motor's power may only be transmitted to one side of the threaded shaft 107. Although a height difference will exist between the nut 108 on the stopped threaded shaft and the nut 108 on the continuing threaded shaft, this structure cannot apply a bending moment to each nut 108, only a vertical load. Therefore, the container loading mechanism 105 will continue to rise or fall. As a result, damage to the components constituting the power transmission mechanism cannot be detected immediately, which may lead to serious personal injury.

[0005] Furthermore, traditional dough hoists often employ threaded shafts with two trapezoidal or square threads having a lead of 24mm or less. In this case, only by increasing the rotation of the threaded shaft can the container loading mechanism be ensured to lift and lower at an appropriate speed. However, when the threaded shaft rotates rapidly during operation or stop, the impact increases, and foreign matter such as lubricating oil (specifically, the lubricating oil in the reducer constituting the power transmission mechanism) and lubricant (specifically, the grease applied to the threaded shaft and nut, and the grease in the bearing housing that supports the threaded shaft in its suspended state) can easily scatter into the surrounding area. Therefore, a housing must be provided to prevent the scattering of lubricating oil and other foreign matter, and the speed of the threaded shaft during start-up and stop must be adjusted using a frequency converter. On the other hand, simply lengthening the lead could lead to a risk of the container loading mechanism falling due to its own weight when the motor stops for maintenance or other tasks. Additionally, the frictional resistance during the lifting and lowering of the container loading mechanism would increase.

[0006] In Japan, the sponge dough method also uses chain-driven elevators to feed dough to mixers or dividers. Chain-driven elevators require frequent chain replacements, making frequent installation and replacement a fundamental part of equipment maintenance. However, because the chain is electrically engaged, it can still operate even with wear or significant slack, making it easy for installers to be careless and fail to install correctly. If this happens, even replacing the chain can lead to premature wear, chain breakage, chain entanglement, and the machine stopping. Furthermore, the chain pins are only a few millimeters in diameter, lacking sufficient impact resistance. Therefore, chain-driven elevators are unsuitable for sponge dough methods that require lifting hundreds of kilograms of dough; threaded elevators should be used instead.

[0007] This invention was made in view of the above-mentioned situation. When a component constituting the power transmission mechanism is damaged, the lifting and lowering of the container loading mechanism can be stopped promptly, and the extent of damage to the component can be quickly assessed. The purpose of this invention is to provide a lifting machine with a simple structure that can prevent serious personal injury accidents. In addition to the above, another purpose of this invention is to provide a lifting machine that can suppress the scattering of foreign matter such as lubricating oil and grease, prevent foreign matter from mixing into the product raw materials inside the container, prevent the container loading mechanism from falling due to its own weight when the motor stops, and also suppress the frictional resistance during the lifting and lowering of the container loading mechanism.

[0008] The present invention is as follows: 1. A hoist with left and right columns, between which a container loading mechanism for lifting and lowering containers is configured. Rotatable threaded shafts are installed inside the left and right columns. The rotation of these threaded shafts drives the container loading mechanism, which is connected to a female threaded bushing, to perform lifting and lowering actions. A support seat is fixed to the side of the container loading mechanism. A support shaft is located on the threaded bushing outside the female thread, with the support shaft at the front end of the threaded bushing embedded in the central hole of the support seat. This is a hoist with the above features.

[0009] 2. A hoist with a support shaft length of 80 to 120 mm embedded in the central hole as described in 1 above.

[0010] 3. A hoist with a drive shaft having two trapezoidal or square threads as described in 1 or 2 above, the lead of which is 26-30 mm.

[0011] 4. The lifting machine for lifting bread dough as described in any one of 1 to 3 above.

[0012] According to the hoist of the present invention, a support seat is provided on the side of the container loading mechanism, and a support shaft is provided on the outer circumferential surface of the nut housing mounted on the screw nut, which is embedded in the central hole of the support seat. Therefore, since the screw nut is cantilevered to the container loading mechanism, when a component constituting the power transmission mechanism is damaged, the motor power is transmitted only to one of the threaded shafts on either the left or right column. This creates a height difference between the screw nuts on the left and right threaded shafts, i.e., the stop shaft and the working shaft, applying a bending moment to each nut, thus allowing the container loading mechanism to stop while tilted to a horizontal plane. As a result, damage to the components constituting the power transmission mechanism can be quickly assessed, preventing serious personal injury accidents.

[0013] Furthermore, when the length of the support seat embedded in the support shaft is 80-120mm, if the embedding length is greater than 80mm, an excessive gap will not be generated between the support seat and the support shaft, preventing the motor's power from being transmitted to only one threaded shaft. Here, the bending moment effectively acts on the nuts of the left and right threaded shafts. On the other hand, if the embedding length is within 120mm, the spacing between the left and right columns can be reduced while ensuring sufficient width of the container loading mechanism.

[0014] Furthermore, the threaded shaft has two trapezoidal or square threads. When the lead of the trapezoidal or square thread is 26-30mm, as long as the lead is above 26mm, even if the rotation of the threaded shaft is slowed down, the container can ensure that the container loading mechanism lifts and lowers at an appropriate speed, preventing the scattering of foreign matter such as lubricating oil and grease caused by the rotation and stopping of the threaded shaft, which could lead to foreign matter mixing into the product raw materials inside the container. On the other hand, if the lead is within 30mm, since the pitch will not be too long, the container loading mechanism will not fall due to its own weight when the motor stops during maintenance operations. Furthermore, it can reduce the frictional resistance during the lifting and lowering of the container loading mechanism. Attached Figure Description

[0015] In the following detailed description, the invention will be further explained by way of non-limiting examples of exemplary embodiments thereof and with reference to the accompanying drawings. The same reference numerals denote the same parts in the drawings.

[0016] Figure 1 This is an exploded perspective view of the bread dough lifter of this embodiment.

[0017] Figure 2 yes Figure 1 Enlarged view of the main parts (decomposed state).

[0018] Figure 3 yes Figure 1 Enlarged view of the main parts (in assembly state).

[0019] Figure 4 This is a cross-sectional view of the container loading mechanism of this embodiment, including the connection portion with the nut.

[0020] Figure 5 This is a side view of the main part of the threaded shaft in this embodiment.

[0021] Figure 6 This is an instruction diagram of the operation of a bread dough lifting machine. (a) shows the state in which the dough cylinder is pushed toward the container loading mechanism, (b) shows the state in which the dough cylinder is loaded onto the container loading mechanism, (c) shows the state in which the container loading mechanism is rising, and (d) shows the state in which the container loading mechanism is flipped at the rising end.

[0022] Figure 7 This is a diagram illustrating the operation of a bread dough lifting machine.

[0023] Figure 8 This is a cross-sectional view of the main part of a bread dough lifter for a comparative example; Figure 9 This is an explanatory diagram used to illustrate a traditional bread dough lifting machine. Detailed Implementation

[0024] The content herein is illustrative in purpose, describing embodiments of the invention and intended to provide the most effective and readily understandable principles and conceptual features of the invention. In this regard, no further structural details beyond those necessary for a basic understanding of the invention are presented; the textual description, in conjunction with the accompanying drawings, illustrates several ways in which the invention can be implemented in practice, enabling those skilled in the art to clearly understand how the invention can be carried out.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. In this embodiment, the "lifting machine" of the present invention is exemplified as a lifting machine for conveying bread dough to a dividing machine or a mixer in a preparation area according to the sponge dough method (see [reference]). Figure 1 Furthermore, examples include a threaded shaft-like structure S comprising a threaded shaft (main or male thread) 7 and a nut (female thread) 8 mating with the screw shaft 7 (see [reference]). Figure 3 ).

[0026] like Figures 1 to 3 As shown, the bread dough lifting machine 1 according to this embodiment is provided with left and right columns (main columns) 2a and 2b, and a dough cylinder 4 (referred to as a "container" in this invention) is placed between the left and right columns 2a and 2b. See also Figure 6 The container loading mechanism 5 has a rotatable threaded shaft 7 for vertical transmission inside each column 2a, 2b. A nut 8, connected to the container loading mechanism 5, is mounted on this threaded shaft 7. Power from the motor 10 is then transmitted to the threaded shaft 7 via a power transmission mechanism 9, causing the threaded shaft 7 to rotate, thereby raising and lowering the container loading mechanism 5 together with the nut 8 (see reference). Figure 6 ).

[0027] The left and right columns 2a and 2b extend vertically and are non-solid columnar structures inside (see...). Figure 4 The columns 2a and 2b are horizontally separated and individually installed. Each column 2a and 2b has a threaded shaft 7 inside, suspended from the upper part by a bearing housing 11 and supported from the lower part by a bearing unit 12. The bearing housing 11 is mounted on a bracket 13 fixed to each column 2a and 2b. Furthermore, two slanted bearings and one thrust bearing are installed inside the bearing housing 11, and high-viscosity grease is sealed within them by a sealing ring. Due to damage to the sealing ring, deterioration, or a decrease in lubricant viscosity caused by heat, the grease may leak from the bearing housing 11.

[0028] exist Figure 1 In the left column 2a, the descriptions of the threaded shaft 7, upper bearing housing 11, and bottom bearing unit 12, as described in the right column 2b, are omitted. Similarly, in the right column 2b, the descriptions of the female thread 8 and guide mechanism 21, as described in the left column 2a, are omitted. Furthermore, Figure 1The label "25" indicates the hopper used to transfer dough to the divider or mixer.

[0029] The container loading mechanism 5 is capable of loading containers from the open front. The container loading mechanism 5 includes left and right side plates 16, a rear plate 17 connecting the left and right side plates 16, and generally L-shaped support plates 18 disposed on the inner side of each side plate 16. Safety brackets 19 are pivotally supported on the outer surfaces of these side plates 16 about a horizontal axis. Safety bars 20 are installed between the safety brackets 19 to prevent the face cylinders 4 loaded on the container loading mechanism 5 from falling off the front of the container loading mechanism 5.

[0030] Each side plate 16 has a guide mechanism 21 on its outer surface for guiding the lifting and lowering of the container loading mechanism 5. The guide mechanism 21 includes a guide shaft 22 and a guide roller 23 mounted on the guide shaft 22. The guide roller 23 moves along the guide surface 24 (see reference 24) inside the columns 2a and 2b as the container loading mechanism 5 rises and falls. Figure 4 The container loading mechanism 5 moves. As a result, it lifts and lowers, and reverses at the rising end side using the support shaft 37 (described later) as a fulcrum (see reference). Figure 6 Furthermore, to prevent lateral vibration, impact-resistant materials such as polyurethane resin are used on the outer periphery of the guide roller 23.

[0031] A support seat 27 is fixedly mounted on the side of the container loading mechanism 5 (specifically, the outer side of the side plate 16). The support seat 27 has a central hole 27a for the insertion of the support shaft 37. The shaft center of the support seat 27 is arranged along the arrangement direction a of the left and right columns 2a and 2b (the relative direction a between the support seat 27 and the support shaft 37) (see reference). Figure 4 Furthermore, the metal material used in the support 27 is softer and more wear-resistant than that used in the support shaft 37 (e.g., bronze (BC, PBC)).

[0032] Threaded shaft 7 has two trapezoidal or square threads (see reference). Figure 5 The lead L of the trapezoidal or square thread can be 26-30 mm (preferably 26-28 mm). In a more specific embodiment, the pitch P of the trapezoidal or square thread is 13 mm, its lead L is 26 mm, and its outer diameter D is 60 mm. Furthermore, a high-viscosity grease is applied to the threaded shaft 7 and the nut 8 (described later). This grease should be replenished periodically (by reapplying lubricant) due to viscosity degradation and dust adhesion.

[0033] Nut housing 32 is mounted on the outer periphery of nut 8. Nut 8 has two trapezoidal or square threads with a lead corresponding to the threaded shaft 7. Nut housing 32 is used to prevent grease from scattering and dust from entering nut 8. In addition, horseshoe-shaped fixing plate 33 and nut guide slider 34 for preventing lateral vibration are mounted on nut housing 32 in this order.

[0034] A support shaft 37 is provided on the outer circumferential surface of the nut housing 32, which can be inserted into the central hole 27a of the support base 27 and is supported by its shaft. The support shaft 37 extends along the arrangement direction a of the left and right columns 2a and 2b (see reference). Figure 4 Additionally, the embedding length L1 of the support shaft 37 can be 80-120 mm (preferably 90-110 mm). In a more specific embodiment, the embedding length L1 is 94 mm. Furthermore, the support shaft 37 is inserted through the guide wheel 38 to absorb lateral impacts on the threaded shaft 7. The guide wheel 38 is made of a metal material (e.g., bronze (BC, PBC) etc.) that is softer and more wear-resistant than the support shaft 37. In addition, a gap 39 is provided on the front end side of the support shaft 37 embedded in the support seat 27 to absorb the lateral movement of the container loading mechanism 5.

[0035] The power transmission unit 9 transmits power from the motor 10 to the threaded shafts 7 of the left and right columns 2a and 2b. This power transmission unit 9 is mounted on a support 41 at the upper end of the columns 2a and 2b. The power transmission unit 9 includes a drive-side reducer 43, a driven-side reducer 44, and a drive shaft 45 disposed between the reducers 43 and 44. The input shaft 43a of the drive-side reducer 43 is connected to the drive shaft of the motor 10 via a tire coupling 46. The output shaft 43b of the drive-side reducer 43 is connected to the upper end of the threaded shaft 7 via a chain coupling 47. This chain coupling 47 is fitted with a coupling housing 48 to prevent dust scattering and intrusion. Furthermore, a gear 50 is mounted on the output shaft 43c of the drive-side reducer 43, and the chain is connected to the gear 50 for detecting the number of rotations of the threaded shaft 7 (i.e., detecting the lifting position of the container loading mechanism 5). Additionally, low-viscosity lubricating oil is sealed within the reducers 43 and 44 by double sealing rings. Due to damage to these sealing rings, there is a possibility of leakage of this lubricating oil from the reducers 43 and 44. Furthermore, vent valves are provided above the reducers 43 and 44 for venting when the lubricating oil becomes hot.

[0036] The drive shaft 45 is horizontally supported by multiple bearing units 51. One end of the drive shaft 45 is connected to the output shaft 43d of the reducer 43 on the power side via a tire coupling 46, and the other end is connected to the input shaft 44a of the reducer 44 on the driven side via a tire coupling 46. The output shaft 44b of the reducer 44 on the driven side is connected to the upper end of the threaded shaft 7 via a chain coupling 47.

[0037] In addition, this bread dough lift 1 is equipped with a human detection sensor (not shown) to detect when an operator is in a dangerous operating area. Upon detection by the human detection sensor, the lift 1 stops working or reports an abnormality through sound or visual display. Furthermore, if the operator's operating sequence is incorrect (e.g., forgetting to set the safety bar 20), this bread dough lift 1 guides the operator to operate in the correct sequence through sound or visual display (e.g., guidance such as "Please lower the safety bar").

[0038] Next, the operation of the bread dough lifting machine 1 with the above-described structure will be explained. First, when the container loading mechanism 5 is in the descending position, the dough cylinder containing the dough is pushed into the container loading mechanism 5 (see reference). Figure 6 a). Next, lower the safety lever 20 to allow the container loading mechanism 5 to load the face cylinder 4 (refer to...). Figure 6 b). Next, the power of the motor 10 is transmitted through the power transmission unit 9, and the container loading mechanism 5 is raised by the rotation of the threaded shaft 7 (see...). Figure 6 c). On the rising end side of the container loading mechanism 5, the guide mechanism 21 causes the container loading mechanism 5 to flip via the guide surface 24 (curved surface portion), feeding the dough in the dough cylinder 4 into the divider or mixer via the hopper 25 (see...). Figure 6 d) Photo). Then, in the reverse order of the above actions, lower the container loading mechanism 5 until the lowering end and raise the safety bar 20, and finally remove the empty cylinder 4 from the container loading mechanism 5.

[0039] In the bread dough lifting machine 1, for safety reasons, the container loading mechanism 5 temporarily stops its ascent before reaching the tipping point during its ascent. Similarly, the container loading mechanism 5 also temporarily stops its descent after tipping, and the subsequent descent is performed by a manual button. In addition, an alarm device is activated when the container loading mechanism 5 is descending.

[0040] Here, when a component constituting the power transmission unit 9 (such as the tire coupling 46, reducers 43, 44, etc.) is damaged, the motor 10 may only be able to transmit power to the threaded shaft 7 on one side of either the left or right columns 2a, 2b. For example, as Figure 7 As shown, when the container loading mechanism 5 rises, with the left threaded shaft 7 becoming the stop shaft and the right threaded shaft 7 becoming the working shaft, a height difference is created between the nuts 8 of the stop shaft 7 and the working shaft 7. Because a bending moment M is applied to each screw nut 8, the container loading mechanism 5 stops in a state of tilt towards the horizontal plane. The tilt angle of the container loading mechanism 5 when it stops is within 15 degrees, and the tilt angle will vary depending on the wear condition of the screw nuts 8.

[0041] As described above, in this type of bread dough lifting machine 1, a support base 27 is provided on the side of the container loading mechanism 5, and a support shaft 37 is provided on the outer peripheral surface of the nut housing 32, which is mounted to the nut 8, so that it can be inserted into the central hole 27a of the support base 27. Thus, the nut 8 is cantilevered to the container loading mechanism 5, so when a component constituting the power transmission unit 9 is damaged, the motor 10 only transmits power to one of the threaded shafts 7 of the left and right columns 2a and 2b. At this time, a height difference will occur between the nut 8 of the stop shaft 7 and the working shaft 7, thereby applying a bending moment to the nut 8, and the container loading mechanism 5 will stop in a state of tilting to the horizontal plane. This allows for quick detection of damage to components constituting the power transmission unit 9, enabling timely repairs and preventing serious personal injury accidents.

[0042] In this embodiment, the embedding length L1 of the support shaft 37 is 80-120 mm. If the embedding length L1 is greater than 80 mm, it is less likely that excessive gaps will occur between the support seat 27 and the support shaft 37. When the power of the motor 10 is transmitted to only one threaded shaft 7, the bending moment M is effectively applied to each nut 8 of the left and right threaded shafts 7. On the other hand, if the embedding length L1 is within 120 mm, it is possible to reduce the spacing between the left and right columns 2a and 2b while ensuring the width of the container loading mechanism 5 sufficiently.

[0043] In this embodiment, the threaded shaft 7 has two trapezoidal or square threads, with a lead L of 26-30 mm. When the lead L is greater than 26 mm, even if the rotation speed of the threaded shaft 7 is slowed down, the container loading mechanism 5 will still be able to lift and lower at an appropriate speed. Simultaneously, it can suppress the scattering of foreign matter such as lubricating oil (specifically, the lubricating oil in the reducers 43 and 44) ​​or grease (specifically, the grease applied to the threaded shaft 7 or nut 8, and the grease in the bearing housing 11 that supports the threaded shaft 7 in the suspended state) when the threaded shaft rotates or stops. This prevents foreign matter from mixing into the dough in the dough cylinder 4. On the other hand, if the lead L is within 30 mm, the appropriate lead length prevents the container loading mechanism 5 from falling due to its own weight when the motor stops for maintenance or other tasks. Furthermore, it reduces the frictional resistance during the lifting and lowering of the container loading mechanism 5.

[0044] Furthermore, in this embodiment, compared with a conventional bread dough lifter (see reference...) Figure 9 Compared to the previous method, it requires more frequent grease replenishment and leveling operations. However, by taking the occurrence of abnormal noise on nut 8 as an opportunity, it is easier to determine when to replenish grease and perform leveling operations.

[0045] like Figure 8As shown, the bread dough lifter 101 used for the comparative example employs a support base 127 provided on the outer peripheral surface of the nut housing 132 mounted on the nut 108, and a central hole of the support base 127 provided on the side of the container loading mechanism 105. The support shaft 137 is embedded in the central hole 127a. In this form, the support base 127 with a relatively large outer diameter must be mounted on the outer peripheral surface of the nut housing 132 by welding or other means, which reduces the installability of the support base 127 compared to the bread dough lifter 1 of the present invention. In addition, space must be provided in the left and right columns 102a and 102b for the support base 127 to pass through when the container loading mechanism 105 is raised or lowered, which reduces the strength of the columns 102a and 102b compared to the bread dough lifter 1 of the present invention.

[0046] Furthermore, the present invention is not limited to the above embodiments, and various modifications may be made within the scope of the present invention according to the purpose and use. That is to say, in the above embodiments, the elevator of the present invention is illustrated as a bread dough elevator 1 for conveying bread dough to the next process, but it is not limited thereto. For example, it can also be used for conveying paste-like food materials other than dough, rubber materials, etc., to the next process.

[0047] Furthermore, in the above embodiments, a container (dough cylinder) 4 with wheels is illustrated, but it is not limited to this; for example, it may also be a container without wheels.

[0048] Industrial availability This invention is widely used as a technology for lifting container loading mechanisms.

[0049] Marker description 1: Bread dough lifter 2a, 2b: Left and right pillars 4: Dough container 5: Container loading mechanism 7: Threaded shaft 8: Nuts 27: Support seat 27a: Center hole 32: Nut housing 37: Support shaft L: Lead L1: Embedding length S: Threaded shaft-like structure.

Claims

1. A hoist, characterized in that, include: Left and right uprights, each with a rotatable threaded shaft inside; A container loading mechanism is configured between the left and right columns for loading containers. A rotatable threaded shaft is provided inside the left and right columns. The threaded shaft is fitted with a nut that is connected to the container loading mechanism. The power of a motor is transmitted to the threaded shaft inside the left and right columns through a power transmission mechanism. The container loading mechanism is raised and lowered by rotating the threaded shaft. A support base is mounted on the side of the container loading mechanism and has a central hole; The support shaft is located on the outside of the nut housing on the nut and can be embedded in the central hole of the support seat; The embedment length of the support shaft into the support seat is 80-120mm; When a component constituting the power transmission mechanism is damaged, and the motor transmits power only to the threaded shaft on one side of the left and right columns, the container loading mechanism will stop while tilted to the horizontal plane.

2. The hoist as described in claim 1, characterized in that, The threaded shaft has two trapezoidal or square threads, and the lead of the trapezoidal or square threads is 26-30 mm.

3. The hoist as described in claim 1 or 2, characterized in that, The aforementioned elevator is used to lift bread dough.

4. The hoist as described in claim 1 or 2, characterized in that, The support shaft is inserted into a guide wheel to absorb lateral impacts on the threaded shaft; The guide wheel is installed between the nut housing and the support base; The guide wheel and the support base are made of a softer metal material than the support shaft.

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