A multi-station flexible and rapid changeover clamping device and method for aero-engine blades

Abstract

This invention provides a multi-station flexible rapid-change clamping device and method for aero-engine blades, comprising: a worm gear transmission device, a detachable positioning base, and a flexible clamping component; in the worm gear transmission device, a rotating handle drives a transmission worm to rotate, which simultaneously drives multiple transmission worm wheels to rotate, and simultaneously drives multiple flexible upper pressure plates to apply a flexible clamping force to the blade; the detachable positioning base is provided with positioning pins for placing and positioning the blade to be clamped; the detachable positioning base is connected to the base by bolts, enabling quick disassembly and replacement to adapt to the clamping requirements of different types of blades. The flexible clamping component provides support for the flexible upper pressure plates while allowing a certain degree of flexible deformation to accommodate differences in blades.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine blade processing technology, and particularly relates to a multi-station flexible and rapid form change clamping device and method for aero-engine blades. Background Technology

[0002] As a core component of the modern aviation industry, the precision of blade processing, inspection, and assembly directly affects engine performance and flight safety. With the development of aero-engines towards higher thrust-to-weight ratios and lighter weights, blade structures are becoming increasingly complex, exhibiting characteristics of thinner walls and curved, irregular shapes, and requiring flexible production in small batches across multiple models. Traditional blade clamping devices generally suffer from low changeover efficiency, insufficient positioning accuracy, and poor multi-station coordination, becoming a technological bottleneck restricting the upgrading of aero-engine manufacturing.

[0003] Current aero-engine blade clamping technology primarily employs fixed fixtures with mechanical locating pins and hydraulic locking. While this type of device ensures basic clamping stability, it has significant drawbacks. For example, different blade models require redesigned dedicated fixtures, and changing models necessitates disassembling and replacing the entire tooling set, which can take several hours. Furthermore, the rigid clamping structure is prone to vibration transmission during high-speed machining, leading to deformation of thin-walled blades. Additionally, the lack of a unified reference surface during multi-station operations affects the accuracy of blade phase consistency testing. Moreover, existing clamping devices generally lack adaptability to extreme conditions such as high-temperature environmental testing and dynamic load impacts, resulting in micro-displacement deviations in blades during thermal cycling tests.

[0004] Current solutions to these problems often shorten changeover time by adding modular components or pneumatic locking mechanisms, but significant limitations remain: while modular design reduces changeover complexity, the modular structure easily introduces accumulated assembly errors; while pneumatic clamping increases speed, it is difficult to achieve highly uniform control of clamping force (local pressure fluctuations exceeding 15%), which can easily damage the blade surface. Furthermore, existing technologies generally lack compatibility with intelligent manufacturing, such as the inability to provide real-time feedback of clamping status data and difficulty in seamlessly integrating with automated changeover robotic arms. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-station flexible and rapid changeover clamping device and method for aero-engine blades, which features multi-station collaboration, high-precision flexible positioning, and rapid adaptive changeover. The invention will effectively improve the manufacturing efficiency and quality consistency of aero-engine blades and is of great significance to promoting the intelligent manufacturing upgrade of aero-equipment.

[0006] The first aspect of the present invention provides a multi-station flexible rapid change clamping device for aero-engine blades, comprising: a worm gear 10, a base 14 and at least one flexible blade clamping unit; The flexible blade clamping unit includes: a flexible blade pressing device, a flexible lower support, and a detachable positioning base; the flexible blade pressing device includes: a left blade flexible pressing plate 1-1, a right blade flexible pressing plate 1-2, two angular contact ball bearing supports, two angular contact ball bearings, a drive shaft 1-5, and a drive worm gear 1-8. Worm 10, flexible lower bracket, detachable positioning base and two angular contact ball bearing brackets are mounted on base 14. Drive shaft 1-5 is rotatably mounted on two angular contact ball bearing brackets via two angular contact ball bearings. Left blade flexible upper pressure plate 1-1 and right blade flexible upper pressure plate 1-2 are fixedly connected to drive shaft 1-5. One end of drive shaft 1-5 is provided with drive worm gear 1-8. The detachable positioning base and the drive shaft 1-5 are arranged along the direction perpendicular to the worm 10. The detachable positioning base is provided with a positioning pin and a positioning groove assembly. The drive worm wheel 1-8 meshes with the worm 10. The flexible lower bracket is arranged at the end of the detachable positioning base away from the worm 10. The tenon at the root of the blade is placed on the positioning groove assembly, the positioning reference surface of the blade is in contact with the positioning pin, and the blade body is placed on the flexible lower support. When the worm gear 10 drives the transmission worm wheel 1-8 to rotate, the transmission shaft 1-5 drives the left blade flexible upper pressure plate 1-1 and the right blade flexible upper pressure plate 1-2 to rotate, so as to press or move away from the blade.

[0007] Optionally, the multi-station flexible and rapid change clamping device for aero-engine blades also includes: a first worm bearing bracket 11 and a second worm bearing bracket 12. The first worm bearing bracket 11 and the second worm bearing bracket 12 are fixedly mounted on the base 14; The two ends of the worm 10 are rotatably mounted in bearings on the first worm bearing bracket 11 and the second worm bearing bracket 12.

[0008] Optionally, the first worm bearing bracket 11, the second worm bearing bracket 12, the flexible lower bracket, and the detachable positioning base are bolted to the base 14.

[0009] Optionally, the worm gear 10 is provided with a rotary crank 13; The rotary handle 13 is connected to the output shaft of the servo drive motor via a flexible coupling, and drives the worm gear 10 to rotate under the drive of the servo drive motor.

[0010] Optionally, the worm gear 10 is welded to the rotary crank 13.

[0011] Optionally, the flexible upper pressure plate 1-1 of the left blade and the flexible upper pressure plate 1-2 of the right blade are connected to the drive shaft 1-5 by a key. The transmission worm gear 1-8 is connected to one end of the transmission shaft 1-5 by a key.

[0012] Optionally, both ends of the drive shaft 1-5 are interference-fitted with two angular contact ball bearings.

[0013] Optionally, the positioning groove group includes two parallel limiting bosses, which are vertically arranged on the upper surface of the base 14. The distance between the two limiting bosses is adapted to the shape of the leaf root; The upper surface of the limiting boss is provided with a guide slope; The limiting boss is used to restrict the circumferential rotation of the blade.

[0014] A second aspect of the present invention provides a multi-station flexible rapid changeover clamping method for aero-engine blades, employing the multi-station flexible rapid changeover clamping device for aero-engine blades as described in any one of the first aspects, the method comprising: Step 1: Positioning and installation of the detachable positioning base and benchmark calibration; Step 2: Place the blade to be clamped on the positioning slot of the detachable positioning base, with the positioning reference surface of the blade in contact with the positioning pin; Step 3: The rotation of the worm gear drives the transmission worm wheel 1-8 to rotate, which in turn causes the transmission shaft 1-5 to drive the left blade flexible upper pressure plate 1-1 and the right blade flexible upper pressure plate 1-2 to rotate, so as to press or move away from the blade.

[0015] This invention provides a multi-station flexible and rapid blade changeover clamping device and method for aero-engine blades, aiming to solve the problems of low clamping efficiency, difficult changeover, and poor adaptability of existing blade fixtures. Through innovative structural design, it achieves simultaneous clamping of multiple blades and rapid changeover, improving production efficiency and flexibility. Based on existing aero-engine blade fixtures, this invention introduces a worm gear drive system as the drive and transmission unit, forming a multi-axis linkage blade clamping device. Simultaneously, it creatively introduces a multi-station clamping mechanism, which works in conjunction with a detachable positioning base. The flexible clamping components on the clamping device not only enable simultaneous clamping, rapid positioning, and changeover of multiple blades, but also effectively reduce the impact of machining vibration transmission and mechanical chatter on engine blades. The parallel connection of multiple flexible blade clamping devices in this invention improves clamping efficiency. By setting multiple clamping units, multiple blades can be clamped simultaneously, significantly improving clamping efficiency compared to traditional single-blade clamping methods, meeting the needs of mass production. The detachable positioning base design of this invention allows for easy replacement of different blade types simply by disassembling and replacing the positioning base, eliminating the need for complex adjustments to the entire fixture. This significantly shortens changeover time and improves production flexibility. The flexible upper pressure plate and flexible support, based on flexible materials, enable adaptive adjustment according to the shape and size of the blades, achieving reliable clamping of different blade types. This expands the fixture's applicability and reduces customization costs. The worm gear mechanism used in this invention offers advantages such as a large transmission ratio, smooth transmission, and good self-locking performance, ensuring the upper pressure plate can smoothly press down and lift, guaranteeing the stability and reliability of blade clamping. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the device described in this invention; Figure 2 These are three views of the device described in this invention; Figure 3 This is a structural diagram of the device described in this invention. Figure 4 This is a structural diagram of the flexible blade clamping device described in this invention; Figure 5 This is a schematic diagram of the flexible upper pressure plate and the flexible lower pressure plate described in this invention; Explanation of reference numerals in the attached figures: 1. First blade flexible pressing device; 2. Second blade flexible pressing device; 3. Third blade flexible pressing device; 4. First flexible lower support; 5. Second flexible lower support; 6. Third flexible lower support; 7. First detachable positioning base; 8. Second detachable positioning base; 9. Third detachable positioning base; 10. Worm; 11. First worm bearing support; 12. Second worm bearing support; 13. Rotating handle; 14. Base; 1-1. Left blade flexible pressing plate; 1-2. Right blade flexible pressing plate; 1-3. First diameter 20mm angular contact ball bearing support; 1-4. First diameter 20mm angular contact ball bearing; 1-5. Drive shaft; 1-6. Second diameter 20mm angular contact ball bearing; 1-7. Second diameter 20mm angular contact ball bearing support; 1-8. Drive worm wheel. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0020] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0022] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0024] The structural composition of the present invention is as follows Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown in the accompanying drawings, the specific structure and specific embodiments of the present invention will be further explained.

[0025] This invention discloses a multi-station flexible rapid-change clamping device and method for aero-engine blades. The device includes: The worm gear transmission device uses a rotating handle to drive the transmission worm to rotate, which in turn drives multiple transmission worm wheels to rotate, and simultaneously drives multiple flexible upper pressure plates to apply a flexible clamping force to the blades.

[0026] A detachable positioning base is provided on the base. The detachable positioning base has multiple positioning slots for placing the blades to be clamped. The detachable positioning base is connected to the base by positioning pins and bolts, which can be quickly disassembled and replaced to meet the clamping requirements of different types of blades.

[0027] The flexible clamping component comprises multiple clamping units. Each clamping unit includes a flexible upper pressure plate and a flexible lower support. The flexible upper pressure plate is connected to a drive shaft, and the rotation of the drive shaft causes the flexible upper pressure plate to move up and down. The flexible upper pressure plate can adaptively adjust to a certain extent according to the shape of the blade, ensuring reliable clamping of different types of blades. The flexible lower support provides support for the blade while allowing for a certain degree of flexible deformation to accommodate differences in blade shape. A detachable positioning base provides support for the flexible upper pressure plate.

[0028] For example, the present invention provides a multi-station flexible rapid change clamping device for aero-engine blades, comprising: a first flexible upper pressing device 1, a second flexible upper pressing device 2, a third flexible upper pressing device 3, a first flexible lower support 4, a second flexible lower support 5, a third flexible lower support 6, a first detachable positioning base 7, a second detachable positioning base 8, a third detachable positioning base 9, a worm gear 10, a first worm gear bearing support 11, a second worm gear bearing support 12, a rotating handle 13, a base 14, a left blade flexible upper pressing plate 1-1, a right blade flexible upper pressing plate 1-2, a first diameter 20mm angular contact ball bearing support 1-3, a first diameter 20mm angular contact ball bearing 1-4, a drive shaft 1-5, a second diameter 20mm angular contact ball bearing 1-6, a second diameter 20mm angular contact ball bearing support 1-7, and a drive worm gear 1-8; The flexible quick-change clamping device includes multiple clamping units. Taking one clamping unit as an example, it includes: a first blade flexible upper pressing device 1, a first flexible lower support 4, and a first detachable positioning base 7. The first blade flexible upper pressing device 1 includes: a left blade flexible upper pressing plate 1-1, a right blade flexible upper pressing plate 1-2, a first diameter 20mm angular contact ball bearing support 1-3, a first diameter 20mm angular contact ball bearing 1-4, a drive shaft 1-5, a second diameter 20mm angular contact ball bearing 1-6, a second diameter 20mm angular contact ball bearing support 1-7, and a drive worm gear 1-8.

[0029] The left blade flexible upper pressure plate 1-1 and the right blade flexible upper pressure plate 1-2 are both connected to the drive shaft 1-5 by a flat key; the left shaft end of the drive shaft 1-5 is interference-fitted with the first diameter 20mm angular contact ball bearing 1-4, and the right shaft end of the drive shaft 1-5 is interference-fitted with the second diameter 20mm angular contact ball bearing 1-6; the first diameter 20mm angular contact ball bearing 1-5 and the second diameter 20mm angular contact ball bearing 1-6 are connected to the first diameter 20mm angular contact ball bearing bracket 1-3 and the first diameter 20mm angular contact ball bearing bracket 1-7; the first diameter 20mm angular contact ball bearing bracket 1-3 and the first diameter 20mm angular contact ball bearing bracket 1-7 are connected to the first diameter 20mm angular contact ball bearing bracket 1-3 and the first diameter 20mm angular contact ball bearing bracket 1-7. Bearing bracket 1-7 is bolted to base 14; transmission worm gear 1-8 is keyed to the right end of transmission shaft 1-5; first flexible lower bracket 4, second flexible lower bracket 5, and third flexible lower bracket 6 are all bolted to base 14; first detachable positioning base 7, second detachable positioning base 8, and third detachable positioning base 9 are all bolted to base 14; both ends of worm 10 are connected to bearings in first worm bearing bracket 11 and second worm bearing bracket 12; first worm bearing bracket 11 and second worm bearing bracket 12 are bolted to base 14; rotating handle 13 is welded to worm 10.

[0030] When using the aero-engine blade clamping device of the present invention, firstly, select the corresponding first detachable positioning base 7, second detachable positioning base 8, and third detachable positioning base 9 according to the blade type, and install them on the base 14. Then, place the blade into the positioning groove of the detachable positioning base to ensure accurate blade positioning. Next, start the drive motor, which drives the rotating handle 13 to rotate. The rotating handle 13 drives the worm gear 10 to rotate, and the worm gear 10 drives the worm wheel to rotate. The worm wheel drives the flexible upper pressure plate to move downward through the transmission shaft. As the flexible upper pressure plate descends, it contacts the blade and undergoes elastic deformation under the action of the blade surface, pressing tightly onto the blade to achieve simultaneous clamping of multiple blades.

[0031] This invention also provides a clamping method for a multi-station flexible rapid changeover clamping device for aero-engine blades. The specific operation process of this device is as follows: Step 1: Positioning and installation of the detachable positioning base and benchmark calibration Place the selected detachable positioning base smoothly along the guide boss of the clamp base, so that the positioning pin mounting hole is initially aligned with the positioning pin post. Gently push the base manually until the positioning pin is fully inserted into the pin hole to form a rough positioning. Then use a torque wrench to apply a preset torque (e.g., 8-12N). m) Tighten the connecting bolts to ensure the mounting surfaces of the positioning base and the clamp base are in close contact. The upper surface of the positioning base is provided with a set of positioning grooves adapted to the shape of the blade root. Each set of positioning grooves includes a limiting boss for restricting the circumferential rotation of the blade and a reference surface for axial positioning. The combination of positioning pins and bolts improves the repeatability of the detachable positioning base, meeting the stringent requirements for positioning references in aero-engine blade machining. The modular design allows a single positioning base to integrate 3-5 sets of different types of positioning grooves, adapting to the differentiated clamping requirements of blades in the same series and avoiding the time-consuming problem of repeated calibration caused by differences in blade models in traditional clamps.

[0032] Step 2: Place the blades Place the blade to be clamped into the positioning groove of the detachable positioning base, ensuring accurate blade positioning. The root of the blade must form an interference fit or a transition fit with the positioning groove of the detachable positioning base, with the specific fit tolerance selected based on the blade material (e.g., titanium alloy, high-temperature alloy) and machining process (milling, grinding). When placing the blade, slowly push its root tenon along the guide slope of the positioning groove until the positioning reference surface of the blade is completely in contact with the axial limiting surface of the positioning groove.

[0033] Step 3: Synchronous clamping control of the worm gear drive mechanism The servo drive motor is started, and its output shaft is coaxially connected to the rotary handle via a flexible coupling. The handle drives the worm to rotate, and the worm drives the worm wheel to rotate. The center hole of the worm wheel is splined to the worm drive shaft. The worm wheel drives the upper pressure plate to move downwards via the drive shaft. During the descent, the flexible upper pressure plate contacts the blades and adaptively adjusts according to the blade shape, clamping multiple blades simultaneously. The drive motor has a built-in encoder that provides real-time feedback of speed and torque signals. When the flexible upper pressure plate contacts the blade surface, the motor torque begins to increase. Through a preset torque-clamping force mathematical model (established through calibration tests), when the detected torque reaches the target value (e.g., 15-25N), the motor clamping force is adjusted accordingly. When the clamping force (m) corresponding to a single blade clamping force of 80-120N is reached, the motor automatically switches to pressure-holding mode to keep the drive shaft stationary. The contact stress between the flexible upper pressure plate and the blade is monitored in real time by a built-in miniature pressure sensor to ensure that the clamping force of each clamping unit maintains consistent error.

[0034] Step 4: Loosen the blades and change shape When it is necessary to release the blade, the drive motor reverses, the upper pressure plate moves upward, and the flexible upper pressure plate separates from the blade. If different types of blades need to be clamped, simply remove the current detachable positioning base, replace it with a suitable detachable positioning base, and repeat the above steps to achieve quick type change.

[0035] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A multi-station flexible and rapid form-changing clamping device for aero-engine blades, characterized in that, include: The worm (10), the base (14), and at least one blade flexible clamping unit; The flexible blade clamping unit includes: a flexible blade pressing device, a flexible lower support, and a detachable positioning base; the flexible blade pressing device includes: a left blade flexible pressing plate (1-1), a right blade flexible pressing plate (1-2), two angular contact ball bearing supports, two angular contact ball bearings, a drive shaft (1-5), and a drive worm gear (1-8). The worm gear (10), flexible lower support, detachable positioning base and two angular contact ball bearing supports are set on the base (14). The drive shaft (1-5) is rotatably set on the two angular contact ball bearing supports through the two angular contact ball bearings. The flexible upper pressure plate (1-1) of the left blade and the flexible upper pressure plate (1-2) of the right blade are fixedly connected to the drive shaft (1-5). A drive worm wheel (1-8) is set at one end of the drive shaft (1-5). The detachable positioning base and the drive shaft (1-5) are arranged in the direction of the vertical worm (10). The detachable positioning base is provided with a positioning pin and a positioning groove group. The drive worm wheel (1-8) meshes with the worm (10). The flexible lower bracket is arranged at the end of the detachable positioning base away from the worm (10). The tenon at the root of the blade is placed on the positioning groove assembly, the positioning reference surface of the blade is in contact with the positioning pin, and the blade body is placed on the flexible lower support. When the worm (10) drives the transmission worm wheel (1-8) to rotate, the transmission shaft (1-5) drives the left blade flexible upper pressure plate (1-1) and the right blade flexible upper pressure plate (1-2) to rotate, so as to press or move away from the blade.

2. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 1, characterized in that, Also includes: First worm bearing bracket (11), second worm bearing bracket (12). The first worm bearing bracket (11) and the second worm bearing bracket (12) are fixedly mounted on the base (14). The two ends of the worm (10) are rotatably mounted in bearings on the first worm bearing bracket (11) and the second worm bearing bracket (12).

3. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 2, characterized in that, The first worm bearing bracket (11), the second worm bearing bracket (12), the flexible lower bracket and the detachable positioning base are bolted to the base (14).

4. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 2, characterized in that, The worm (10) is equipped with a rotating rocker (13); The rotary handle (13) is connected to the output shaft of the servo drive motor through a flexible coupling, and drives the worm gear (10) to rotate under the drive of the servo drive motor.

5. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 4, characterized in that, The worm (10) is welded to the rotary crank (13).

6. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 1, characterized in that, The flexible upper pressure plate (1-1) of the left blade and the flexible upper pressure plate (1-2) of the right blade are connected to the drive shaft (1-5) with a key. The transmission worm gear (1-8) is connected to one end of the transmission shaft (1-5) by a key.

7. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 1, characterized in that, The two ends of the drive shaft (1-5) are interference-fitted with two angular contact ball bearings.

8. The multi-station flexible rapid-change clamping device for aero-engine blades according to claim 1, characterized in that, The positioning groove group includes two parallel limiting bosses, which are vertically arranged on the upper surface of the base (14); The distance between the two limiting bosses is adapted to the shape of the leaf root; The upper surface of the limiting boss is provided with a guide slope; The limiting boss is used to restrict the circumferential rotation of the blade.

9. A multi-station flexible and rapid form change clamping method for aero-engine blades, characterized in that, The method of using the multi-station flexible rapid change clamping device for aero-engine blades as described in any one of claims 1-8 includes: Step 1: Positioning and installation of the detachable positioning base and benchmark calibration; Step 2: Place the blade to be clamped on the positioning slot of the detachable positioning base, with the positioning reference surface of the blade in contact with the positioning pin; Step 3: The rotation of the worm gear drives the transmission worm wheel (1-8) to rotate, which causes the transmission shaft (1-5) to drive the left blade flexible upper pressure plate (1-1) and the right blade flexible upper pressure plate (1-2) to rotate, so as to press or move away from the blade.

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