Adjustable double-side forming die

Abstract

The utility model discloses an adjustable double-side forming die which comprises a bottom plate, a base is installed on the bottom plate, a left lower die and a right lower die are installed on the base in a relative sliding mode, the left lower die and the right lower die are driven by a horizontal moving mechanism to move close to or away from each other, and a cross-shaped connecting plate is arranged corresponding to the bottom plate. The cross-shaped connecting plate is externally connected with a linear air cylinder, and a left upper die and a right upper die are arranged on the cross-shaped connecting plate corresponding to the left lower die and the right lower die. According to the utility model, the pins of various flat packaging devices with different specifications can be formed, and the pins of the flat packaging devices with top outgoing lines, middle outgoing lines and bottom outgoing lines can be formed.

Description

Technical Field

[0001] The utility model belongs to the technical field of forming molds, and particularly relates to an adjustable double-sided forming mold for flat packaging devices. Background Art

[0002] Flat packaging devices are an electronic component packaging technology, among which the most representative ones are quad flat package (QFP) and quad flat no-lead package (QFN). Flat packaging devices need to form their pins into a specific shape so as to be effectively connected to the circuit board. However, the existing forming molds can only be applicable to devices of a single specification and can only form one pin shape. Therefore, how to design a forming mold with a wider application range has become the direction of efforts of technicians in this field. Summary of the Utility Model

[0003] The purpose of the utility model is to provide an adjustable double-sided forming mold, which can completely solve the deficiencies of the above-mentioned existing technologies.

[0004] The purpose of the utility model is achieved by the following technical solutions:

[0005] An adjustable double-sided forming mold includes a bottom plate, on which a base is installed. A left lower mold and a right lower mold are slidably installed on the base relatively. The left lower mold and the right lower mold are driven by a horizontal movement mechanism to move closer or farther away. A cross connecting plate is provided corresponding to the bottom plate, and a linear cylinder is externally connected to the cross connecting plate. An upper left mold and an upper right mold are provided on the cross connecting plate corresponding to the left lower mold and the right lower mold.

[0006] Further, the left lower mold includes a left lower template, on which a left lower mold forming plate is installed. A left shoulder height adjusting plate is slidably arranged on one side of the left lower mold forming plate, and a left material receiving block is arranged on the other side.

[0007] The right lower mold includes a right lower template, on which a right lower mold forming plate is installed. A right shoulder height adjusting plate is slidably arranged on one side of the right lower mold forming plate opposite to the left shoulder height adjusting plate, and a right material receiving block is arranged on the other side.

[0008] A slide rail is provided on the top surface of the base, and both the left lower template and the right lower template are slidably matched with the slide rail.

[0009] Material receiving grooves are provided on both the left and right material receiving blocks.

[0010] Further, the upper left mold includes an upper left template, a left U-shaped block is installed at one end of the upper left template, an upper left mold mounting plate is installed on the inner side of the bottom of the left U-shaped block, mounting holes are provided in the upper left mold mounting plate, and an upper left mold forming plate and a left pressing plate are movably arranged in the mounting holes.

[0011] The upper right mold includes an upper right template. At one end of the upper right template, a right U-shaped block is installed. Inside the bottom of the right U-shaped block, an upper right mold mounting plate is installed. Mounting holes are provided on the upper right mold mounting plate, and an upper right mold forming plate and a right pressing plate are movably arranged in the mounting holes.

[0012] The upper left mold forming plate is arranged opposite to the left shoulder height adjusting plate, and the upper right mold forming plate is arranged opposite to the right shoulder height adjusting plate. Forming surfaces are provided on the top surfaces of the lower left mold forming plate and the lower right mold forming plate, and the left pressing plate and the right pressing plate are arranged corresponding to the forming surfaces.

[0013] Long round holes are correspondingly provided on both sides of the cross connecting plate. The upper left template and the upper right template are both connected to the cross connecting plate through screws passing through the long round holes.

[0014] An intermediate plate is installed at the bottom of the cross connecting plate. The two ends of the intermediate plate correspondingly extend into the left U-shaped block and the right U-shaped block. A spring mounting plate is arranged below the intermediate plate. A plurality of springs are installed between the spring mounting plate and the intermediate plate. The two ends of the spring mounting plate correspondingly extend into the left U-shaped block and the right U-shaped block, and the bottom surface of the spring mounting plate contacts the top surfaces of the upper left mold forming plate, the left pressing plate, the upper right mold forming plate, and the right pressing plate.

[0015] Guide columns are provided between the lower left template and the upper left template and between the lower right template and the upper right template. Guide sleeves are installed on both the upper left template and the upper right template, and the guide sleeves are in sliding fit with the guide columns.

[0016] Furthermore, it further includes a shoulder height adjusting plate lifting mechanism, which includes a lifting motor. A motor fixing shell is installed at the bottom of the bottom plate. The lifting motor is fixedly installed at the bottom of the motor fixing shell. The output end of the lifting motor extends into the motor fixing shell and is installed with a driving wheel. A driven wheel is correspondingly installed in the motor fixing shell. The driving wheel and the driven wheel are connected by a belt. A nut is fixedly installed inside the driven wheel. The nut is in threaded fit with a lead screw. The top end of the lead screw is connected to a movable tube. The top end of the movable tube is connected to a movable plate. The top surface of the movable plate contacts the bottom surfaces of the left and right shoulder height adjusting plates.

[0017] Furthermore, a vertical slide rail is installed at the bottom of the bottom plate. A vertical slider is in sliding fit with the vertical slide rail. The bottom end of the lead screw is connected to the vertical slider through an L connecting plate.

[0018] Further, the horizontal moving mechanism includes a horizontal motor. A motor bracket is installed on the base, and the horizontal motor is fixed on the motor bracket. A support is installed on the lower left template, and a left screw sleeve is fixed on the support. A left screw rod is in threaded engagement with the left screw sleeve. A support is installed on the lower right template, and a right screw sleeve is fixed on the support. A right screw rod is in threaded engagement with the right screw sleeve. The thread directions of the left and right screw rods are opposite. One end of the left screw rod is rotatably connected to a screw rod seat, and the screw rod seat is fixed on the base. The other end of the left screw rod is connected to one end of the right screw rod through a connecting shaft. The other end of the right screw rod is connected to the output end of the horizontal motor through a belt pulley transmission mechanism.

[0019] Compared with the prior art, the beneficial effects of the present utility model are as follows: The structure is simple and the design is reasonable. It can realize the pin forming of various flat package devices with different specifications, and can form the pins of flat package devices with top wire outlet, middle wire outlet, and bottom wire outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a three-dimensional structural schematic diagram of the present utility model;

[0021] Figure 2 is Figure 1 a three-dimensional structural schematic diagram after removing the top plate;

[0022] Figure 3 is a top view of the present utility model after removing the linear cylinder;

[0023] Figure 4 is a three-dimensional structural schematic diagram of the present utility model after removing the linear cylinder;

[0024] Figure 5 is a partial view of the upper left mold and upper right mold parts of the present utility model;

[0025] Figure 6 is a diagram showing the mating relationship of the upper left mold mounting plate, upper left mold forming plate, and left pressing plate of the present utility model;

[0026] Figure 7 is an exploded structural schematic diagram of the upper left mold mounting plate, upper left mold forming plate, and left pressing plate of the present utility model;

[0027] Figure 8 is a partial view of the lower left mold and lower right mold parts of the present utility model;

[0028] Figure 9 is a structural schematic diagram of the horizontal moving mechanism of the present utility model;

[0029] Figure 10 is a structural schematic diagram of the bottom of the present utility model;

[0030] Figure 11It is a positional relationship diagram between the movable plate and the lower left template and the lower right template in the present utility model;

[0031] Figure 12 It is a structural schematic diagram of the lifting mechanism of the shoulder height adjusting plate in the present utility model. Detailed implementation manners

[0032] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0033] As Figures 1 to 6 shown, an adjustable double-sided forming die includes a bottom plate 1, a base 2 is installed on the bottom plate 1, a lower left die 3 and a lower right die 4 are slidably installed on the base 2 relatively, the lower left die 3 and the lower right die 4 are driven by a horizontal movement mechanism 5 to move closer or farther away, a cross connecting plate 6 is provided corresponding to the bottom plate 1, a linear cylinder 7 is externally connected to the cross connecting plate 6, and an upper left die 8 and an upper right die 9 are provided on the cross connecting plate 6 corresponding to the lower left die 3 and the lower right die 4. During actual assembly, the linear cylinder 7 is fixedly installed on a top plate 10, and the output end of the linear cylinder 7 is connected to the cross connecting plate 6.

[0034] In this embodiment, the lower left die 3 includes a lower left template 301, a lower left die forming plate 302 is installed on the lower left template 301, a left shoulder height adjusting plate 303 is slidably arranged on one side of the lower left die forming plate 302, and the left and right sides of the left shoulder height adjusting plate 303 are inserted into the sliding grooves provided on the lower left die forming plate 302, so as to be able to slide up and down. On the other side of the lower left die forming plate 302, a left material receiving block 304 is provided, and a material receiving groove 305 is provided on the left material receiving block 304, and the material receiving groove 305 includes an inclined surface and a material storage groove.

[0035] The lower right die 4 includes a lower right template 401, a lower right die forming plate 402 is installed on the lower right template 401, a right shoulder height adjusting plate 403 is slidably arranged on the side of the lower right die forming plate 402 opposite to the left shoulder height adjusting plate 303, and the left and right sides of the right shoulder height adjusting plate 403 are inserted into the sliding grooves provided on the lower right die forming plate 402, so as to be able to slide up and down. On the other side, a right material receiving block 404 is provided, and a material receiving groove 405 is provided on the right material receiving block 404, and the material receiving groove 405 includes an inclined surface and a material storage groove.

[0036] A slide rail 11 is provided on the top surface of the base 2, the lower left template 301 and the lower right template 401 are both slidably fitted on the slide rail, and the lower left die forming plate 302 and the lower right die forming plate 402 are vertically arranged opposite to each other.

[0037] In this embodiment, the upper left mold 8 includes an upper left template 801. At one end of the upper left template 801, a left U-shaped block 802 is installed. Inside the bottom of the left U-shaped block 802, an upper left mold mounting plate 803 is installed. Mounting holes are provided on the upper left mold mounting plate 803, and an upper left mold forming plate 804 and a left pressing plate 805 are movably arranged in the mounting holes.

[0038] The upper right mold 9 includes an upper right template 901. At one end of the upper right template 901, a right U-shaped block 902 is installed. Inside the bottom of the right U-shaped block 902, an upper right mold mounting plate 903 is installed. Mounting holes are provided on the upper right mold mounting plate 903, and an upper right mold forming plate 904 and a right pressing plate 905 are movably arranged in the mounting holes.

[0039] The upper left mold forming plate 804 is arranged opposite to the left shoulder height adjusting plate 303, and the upper right mold forming plate 904 is arranged opposite to the right shoulder height adjusting plate 403. Forming surfaces 12 are provided on the top surfaces of the lower left mold forming plate 302 and the lower right mold forming plate 402, and the left pressing plate 805 and the right pressing plate 905 are arranged corresponding to the forming surfaces 12.

[0040] Long circular holes 13 are correspondingly provided on both sides of the cross connecting plate 6. The upper left template 801 and the upper right template 901 are both connected to the cross connecting plate 6 by screws passing through the long circular holes 13, so that the upper left and right templates 801, 901 can move left and right along the long circular holes 13.

[0041] An intermediate plate 14 is installed at the bottom of the cross connecting plate 6. The two ends of the intermediate plate 14 correspondingly extend into the left U-shaped block 802 and the right U-shaped block 902. A spring mounting plate 15 is arranged below the intermediate plate 14, and a plurality of springs 16 are installed between the spring mounting plate 15 and the intermediate plate 14. The two ends of the spring mounting plate 15 correspondingly extend into the left U-shaped block 802 and the right U-shaped block 902, and the bottom surface of the spring mounting plate 15 contacts the top surfaces of the upper left mold forming plate 804, the left pressing plate 805, the upper right mold forming plate 904 and the right pressing plate 905;

[0042] Guide posts 17 are provided between the lower left template 301 and the upper left template 801 and between the lower right template 401 and the upper right template 901. Guide sleeves 18 are installed on the upper left template 801 and the upper right template 901, and the guide sleeves 18 are in sliding fit with the guide posts 17.

[0043] In this embodiment, it further includes a shoulder height adjusting plate lifting mechanism 19, which includes a lifting motor 1901. A motor fixing case 1902 is installed at the bottom of the bottom plate 1. The lifting motor 1901 is fixedly installed at the bottom of the motor fixing case 1902. The output end of the lifting motor 1901 extends into the motor fixing case 1902 and is installed with a driving wheel 1903. A driven wheel 1904 is correspondingly installed in the motor fixing case 1902. The driving wheel 1903 and the driven wheel 1904 are connected by a belt (not shown in the figure). A nut is fixedly installed inside the driven wheel 1904. The nut is in threaded fit with a lead screw 1905. The top end of the lead screw 1905 is connected to a movable pipe 1906. The top end of the movable pipe 1906 is connected to a movable plate 1907. The top surface of the movable plate 1907 contacts the bottom surfaces of the left and right shoulder height adjusting plates 303 and 403. Installation cavities 20 are provided below the left and right lower die forming plates 302 and 402. The movable plate 1907 is arranged in the installation cavity 20. By driving the driving wheel 1903 to rotate through the lifting motor 1901, the nut is driven to rotate through the driven wheel 1904, and then the lead screw 1905 is driven to move up and down. The movable plate 1907 is driven to move through the lead screw 1905, so as to adjust the height at which the left and right shoulder height adjusting plates 303 and 403 extend out of the top surfaces of the left and right lower die forming plates 302 and 402.

[0044] In this embodiment, a vertical slide rail 21 is installed at the bottom of the bottom plate 1. A vertical slider 22 is slidably fitted on the vertical slide rail 21. The bottom end of the lead screw 1905 is connected to the vertical slider 22 through an L-shaped connecting plate 23. A position sensor can be arranged on the vertical slide rail 21 for detecting the displacement of the lead screw 1905 moving up and down.

[0045] In this embodiment, the horizontal moving mechanism 5 includes a horizontal motor 501. A motor support 502 is installed on the base 2. The horizontal motor 501 is fixed on the motor support 502. A support 503 is installed on the lower left template 301. A left screw sleeve 504 is fixed on the support 503. A left lead screw 505 is in threaded fit with the left screw sleeve 504. A support 503 is installed on the lower right template 401. A right screw sleeve 506 is fixed on the support 503. A right lead screw 507 is in threaded fit with the right screw sleeve 506. The thread directions of the left and right lead screws 505 and 507 are opposite. One end of the left lead screw 505 is rotatably connected to a screw seat 508. The screw seat 508 is fixed on the base 2. The other end of the left lead screw 505 is connected to one end of the right lead screw 507 through a connecting shaft 509. The other end of the right lead screw 507 is connected to the output end of the horizontal motor 501 through a belt transmission mechanism. Specifically, pulleys are correspondingly installed at the output end of the horizontal motor 501 and the end of the right lead screw 507. The pulleys are connected by a belt. By driving the right lead screw 507 and the left lead screw 505 to rotate simultaneously through the horizontal motor 501, since the thread directions of the left and right lead screws 505 and 507 are opposite, the lower left and right templates 301 and 401 can move towards or away from each other.

[0046] Working principle:

[0047] First, the lifting motor 1901 works, driving the movable plate 1907 to move upward through the lead screw 1905. The movable plate 1907 pushes the left and right shoulder height adjusting plates 303 and 403 to extend out of the top surfaces of the left and right lower die forming plates 302 and 402 to the required height. Then, the horizontal motor 501 works, driving the right lead screw 505 and the left lead screw 507 to rotate simultaneously, thereby driving the left and right lower die forming plates 302 and 402 and the left and right upper die forming plates 804 and 904 to approach each other to the required distance. At this time, the flat package device to be processed (which mainly includes a chip carrier in the middle and external pins) is placed between the left and right shoulder height adjusting plates 303 and 403. Specifically, the chip carrier is located between the inner side walls of the left and right shoulder height adjusting plates 303 and 403, and the pins are placed on the top surfaces of the left and right shoulder height adjusting plates 303 and 403. Finally, the linear cylinder 7 drives the upper left die 8 and the upper right die 9 to move downward simultaneously through the cross connecting plate 6. When the left and right upper die forming plates 804 and 904 are butted against the left and right shoulder height adjusting plates 303 and 403, the pins are pressed between the left and right upper die forming plates 804 and 904 and the left and right shoulder height adjusting plates 303 and 403. The upper left die 8 and the upper right die 9 continue to move downward, and the left and right upper die forming plates 804 and 904 push the spring mounting plate 15 upward, and the spring 16 is compressed until the bottom surfaces of the left and right pressing plates 805 and 905 contact the corresponding forming surfaces 12. The upper left die 8 and the upper right die 9 continue to move downward, causing the left and right upper die mounting plates 803 and 903 to continue to move downward a certain distance, cutting off the excess portions of the outer ends of the pins, and the cut-off materials fall into the corresponding material receiving grooves. Then, pause for a few seconds. After the pins are completely formed, the linear cylinder 7 drives the upper left die 8 and the upper right die 9 to move upward and reset through the cross connecting plate 6.

[0048] Thus, it can be seen that the present utility model can realize the pin forming of various flat package devices with different specifications, and can form the pins of flat package devices with top lead-out, middle lead-out, and bottom lead-out.

[0049] Similarly, it should be understood that, in order to streamline the present disclosure and help understand one or more of the various aspects of the utility model, in the above description of the exemplary embodiments of the utility model, the various features of the utility model are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting the intention that the claimed utility model requires more features than those expressly recited in each claim. Rather, as reflected in the following claims, the aspects of the utility model lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the utility model.

[0050] Those skilled in the art can understand that the modules in the devices in the embodiments can be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all the processes or units of any method or device thus disclosed. Unless otherwise explicitly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) can be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0051] In addition, those skilled in the art can understand that although some of the embodiments herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present utility model and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0052] It should be noted that the above embodiments illustrate the present utility model rather than limit it, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present utility model can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In the unit claims listing several devices, several of these devices can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names.

[0053] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An adjustable double-sided forming die, characterized in that: It includes a bottom plate, on which a base is installed. A lower left die and a lower right die are slidably installed on the base. The lower left die and the lower right die are driven by a horizontal movement mechanism to move closer or farther away. A cross connecting plate is provided corresponding to the bottom plate. The cross connecting plate is externally connected to a linear cylinder, and an upper left die and an upper right die are provided on the cross connecting plate corresponding to the lower left die and the lower right die.

2. The adjustable bilateral forming die according to claim 1, wherein: The lower left die includes a lower left template, on which a lower left die forming plate is installed. A left shoulder height adjusting plate is slidably arranged on one side of the lower left die forming plate, and a left material receiving block is arranged on the other side. The lower right die includes a lower right template, on which a lower right die forming plate is installed. A right shoulder height adjusting plate is slidably arranged on one side of the lower right die forming plate opposite to the left shoulder height adjusting plate, and a right material receiving block is arranged on the other side. A slide rail is provided on the top surface of the base, and both the lower left template and the lower right template are slidably fitted on the slide rail. Material receiving grooves are provided on both the left and right material receiving blocks.

3. The adjustable bilateral forming die according to claim 2, wherein: The upper left die includes an upper left template. A left U-shaped block is installed at one end of the upper left template. An upper left die mounting plate is installed inside the bottom of the left U-shaped block. Mounting holes are provided in the upper left die mounting plate, and an upper left die forming plate and a left pressing plate are movably arranged in the mounting holes. The upper right die includes an upper right template. A right U-shaped block is installed at one end of the upper right template. An upper right die mounting plate is installed inside the bottom of the right U-shaped block. Mounting holes are provided in the upper right die mounting plate, and an upper right die forming plate and a right pressing plate are movably arranged in the mounting holes. The upper left die forming plate is arranged opposite to the left shoulder height adjusting plate, and the upper right die forming plate is arranged opposite to the right shoulder height adjusting plate. Forming surfaces are provided on the top surfaces of both the lower left die forming plate and the lower right die forming plate, and the left pressing plate and the right pressing plate are arranged corresponding to the forming surfaces. Long circular holes are correspondingly provided on both sides of the cross connecting plate. Both the upper left template and the upper right template are connected to the cross connecting plate through screws passing through the long circular holes. An intermediate plate is installed at the bottom of the cross connecting plate. Both ends of the intermediate plate correspondingly extend into the left U-shaped block and the right U-shaped block. A spring mounting plate is provided below the intermediate plate, and a plurality of springs are installed between the spring mounting plate and the intermediate plate. Both ends of the spring mounting plate correspondingly extend into the left U-shaped block and the right U-shaped block, and the bottom surface of the spring mounting plate contacts the top surfaces of the upper left die forming plate, the left pressing plate, the upper right die forming plate, and the right pressing plate. Guide columns are provided between the lower left template and the upper left template and between the lower right template and the upper right template. Guide sleeves are installed on both the upper left template and the upper right template, and the guide sleeves are slidably fitted with the guide columns.

4. The adjustable double-sided forming die according to claim 3, characterized in that: It further includes a shoulder height adjusting plate lifting mechanism, which includes a lifting motor. A motor fixing shell is installed at the bottom of the bottom plate. The lifting motor is fixedly installed at the bottom of the motor fixing shell. The output end of the lifting motor extends into the motor fixing shell and is installed with a driving wheel. A driven wheel is correspondingly installed inside the motor fixing shell. The driving wheel and the driven wheel are connected by a belt. A nut is fixedly installed inside the driven wheel. The nut is threadedly fitted on a lead screw. The top end of the lead screw is connected to a movable tube, and the top end of the movable tube is connected to a movable plate. The top surface of the movable plate contacts the bottom surfaces of the left and right shoulder height adjusting plates.

5. The adjustable bilateral forming die according to claim 4, characterized in that: A vertical slide rail is installed at the bottom of the bottom plate, and a vertical slider is slidably fitted on the vertical slide rail. The bottom end of the lead screw is connected to the vertical slider through an L-shaped connecting plate.

6. The adjustable double-sided forming die according to claim 5, characterized in that: The horizontal movement mechanism includes a horizontal motor. A motor bracket is installed on the base, and the horizontal motor is fixed on the motor bracket. A support is installed on the lower left template, and a left screw sleeve is fixed on the support. A left screw rod is in threaded fit with the left screw sleeve. A support is installed on the lower right template, and a right screw sleeve is fixed on the support. A right screw rod is in threaded fit with the right screw sleeve. The thread directions of the left and right screw rods are opposite. One end of the left screw rod is rotatably connected to a screw rod seat, and the screw rod seat is fixed on the base. The other end of the left screw rod is connected to one end of the right screw rod through a connecting shaft. The other end of the right screw rod is connected to the output end of the horizontal motor through a belt pulley transmission mechanism.

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