Method for grinding an elongated piece and corresponding multi-piece synchronous grinding apparatus

Abstract

The application relates to an elongated piece grinding method and a corresponding multi-piece synchronous grinding device. Multiple workpiece sleeves are arranged on the same workpiece clamp, the main body parts of multiple elongated pieces are respectively inserted into different workpiece sleeves, the same workpiece pressing device is used to press the elongated pieces from the rear end to the front, the tail of the elongated piece is clamped outside the rear end of the workpiece sleeve, the multiple sets of fixed workpiece sleeves and elongated pieces on the workpiece clamp are ground together, the workpiece clamp of the grinding device is provided with a fixed row plate composed of a base plate and multiple workpiece sleeves, the workpiece sleeves are located on the front side of the base plate and are arranged in parallel on the same plane, the rear end of the workpiece sleeve is screw-connected to the base plate, and the rear side of the base plate is provided with a workpiece pressing device used for pressing the rear end of the workpiece forward. The application is suitable for multi-piece synchronous grinding of elongated workpieces, can reduce or avoid workpiece bending in the grinding process, and improves the grinding quality.

Description

Technical Field

[0001] This invention relates to a grinding method for slender parts and corresponding equipment for simultaneous grinding of multiple workpieces. Background Technology

[0002] In practice, various types of slender workpieces require end grinding. For example, the needle knife, which combines an acupuncture needle and a scalpel, consists of a handle, a needle body, and a cutting edge, and is generally made of metal. It resembles both a needle and a knife in shape. Currently, general-purpose grinding machines are not suitable for grinding such slender workpieces. If a grinding machine is used, the workpiece is prone to bending, sliding, or shifting on the grinding wheel due to the force applied to the grinding end, resulting in an uneven needle tip, low production efficiency, and a high scrap rate.

[0003] Specialized grinding technologies for slender workpieces have been developed. For example, Chinese patent document CN109986465A discloses a fixture, grinding tooling, and grinding method for slender workpieces. The fixture comprises two matching half-molds joined together. Each half-mold includes: an adjustment groove, which is a recess formed along the length of the half-mold on its mating surface; a fastening mechanism to keep the two half-molds relatively stationary after mating; and a grinding tooling for slender workpieces, including installation, disassembly, and grinding installation tools. This invention, by clamping batches of slender workpieces in the fixture after the two half-molds are joined, and using the grinding tooling to assist in placing, adjusting, and installing the slender workpieces, completes the grinding of slender workpieces with different angles, symmetrical cutting edges on both sides, and no sharp corners on either side in a simple and effective manner. This achieves batch processing of slender workpieces with low production cost, high production efficiency, and low product defect rate. Chinese patent document CN107745293A discloses a device for grinding the tip of a sterile needle knife. This device is installed on one side of the rotating station of a rotary feeder that holds the sterile needle knife. It includes a frame, a traveling base frame, a linear slide rail, a sliding rail seat, an upper grinding mounting plate, a lower grinding mounting plate, an upper grinding cylinder, a lower grinding cylinder, an upper grinding clamping plate, and a lower grinding clamping plate. The upper and lower grinding clamping plates match and close together, clamping the sterile needle knives arranged on the rotating station between the grinding sections of the two grinding clamping plates. After the upper and lower grinding clamping plates close together, the cutting edge of the sterile needle knife is ground as a whole. Chinese patent document CN110052927A discloses a special grinding fixture for drug-feeding needles and a method for batch grinding. The needle tip is ground using a special grinding fixture, which includes a special fixture and a grinding installation fixture. The special fixture is composed of two half-molds with matching shapes that are closed together. The grinding installation fixture includes a third mounting groove and a second workpiece support surface. The third mounting groove is a downward-facing slot on the upper surface of the grinding installation fixture. By clamping the drug-feeding needles to be processed in batches in the special fixture, the grinding fixture assists in placing, adjusting, and closing the mold for the drug-feeding needles. The simple and effective steps complete the grinding of drug-feeding needles with different angles, symmetrical front and back blades, and no sharp edges on the left and right sides. These existing technologies each have their own characteristics and can be used to grind slender workpieces, but they are complex in structure and inconvenient to operate. In particular, the workpiece needs to be extended a certain length from the mold, and it is still prone to bending to a certain extent, which restricts the improvement of grinding quality. Therefore, in practice, high-quality grinding of such workpieces still depends on manual operation. Not only is the grinding quality greatly affected by the personal factors of the operator, but the work efficiency is also low. Summary of the Invention

[0004] The purpose of this invention is to provide a grinding method for slender parts and a multi-workpiece synchronous grinding device for implementing the method, so as to reduce or avoid workpiece bending during the grinding process and provide favorable conditions for improving the quality of mechanized grinding of slender workpieces.

[0005] The technical solution of the present invention is: a grinding method for slender parts, wherein the main body of the slender part (or slender workpiece, or simply workpiece) is fixedly inserted into the workpiece sleeve, and the workpiece sleeve and the slender part, which are fixed together, are ground together according to the grinding requirements of the slender part.

[0006] Furthermore, multiple workpiece sleeves are set on the same workpiece fixture (hereinafter referred to as fixture), and the main body of multiple slender parts are inserted into different workpiece sleeves respectively. The same workpiece clamping device is used to clamp each slender part from the rear end to the front. The tail of the slender part is stuck outside the rear end of the workpiece sleeve, thereby fixing the slender part on the workpiece sleeve. The workpiece sleeves and slender parts on the workpiece fixture are ground together.

[0007] Furthermore, a cylindrical grinding wheel shaft is used to perform synchronous grinding of various sets of workpiece sleeves and slender parts on the same fixture.

[0008] The grinding angle is controlled or adjusted according to the grinding requirements of the cutting edge (edge) of the slender part.

[0009] This method for grinding slender parts can be used to grind the cutting edge at the front end of slender parts. This method can be implemented using any of the multi-workpiece synchronous grinding equipment disclosed in this invention that is suitable for slender parts, to grind the cutting edge at the front end of the slender part.

[0010] This invention relates to a multi-workpiece synchronous grinding equipment suitable for slender parts. It can employ any of the slender part grinding methods disclosed in this invention to perform synchronous grinding of multiple workpieces. The equipment includes a workpiece fixture (hereinafter referred to as the fixture), which has a base plate. Several workpiece sleeves are mounted on the base plate, located on the front side of the base plate and arranged parallel to each other on the same plane, forming a row with the base plate. The base plate has sleeve through holes for mounting the workpiece sleeves. The rear end of each workpiece sleeve is detachably connected (in a detachable connection manner) to the sleeve through hole on the base plate. A workpiece clamping device is provided on the rear side of the base plate to press the rear end of the workpiece forward. Before grinding, the main body portions of multiple slender parts to be ground are inserted into different workpiece sleeves through different threaded through holes. The workpiece clamping device presses the rear end of each slender part forward, fixing each slender part to its respective workpiece sleeve. The length of the workpiece sleeve is adapted to the length of the main body portion of the slender part, ensuring that the cutting edge of the slender part does not extend beyond the front end of the workpiece sleeve.

[0011] Preferably, the sleeve through hole is provided with an internal thread to form a threaded through hole, and the rear part of the workpiece sleeve is provided with an external thread to be threadedly connected to the sleeve through hole, thereby realizing the detachable connection of the rear end of the workpiece sleeve on the substrate.

[0012] Preferably, in the above case, the rear end of the workpiece sleeve is aligned with the rear end of the sleeve through hole of the substrate.

[0013] Preferably, in the above case, the rear end of the workpiece sleeve is provided with a chamfered structure, or in other words, the rear end is a tapered (frustum-shaped) opening / flared opening, to facilitate the insertion of slender parts.

[0014] Preferably, the sleeve through-hole is a stepped hole, that is, it is divided into two sections, front and rear, both of which are holes of equal diameter. The diameter of the front section is larger than that of the rear section and is adapted to the outer diameter of the workpiece sleeve. The rear section of the workpiece sleeve is inserted into the front section of the sleeve through-hole and fits tightly with the sleeve through-hole, thereby realizing the detachable connection of the rear section of the workpiece sleeve on the substrate. The tightness of the fit between the rear section of the workpiece sleeve and the front section of the sleeve through-hole should allow manual insertion and removal of the workpiece sleeve, but it should not move or come out on its own due to external force during operation after insertion.

[0015] Preferably, in the above-described case, the rear end of the workpiece sleeve abuts against the annular end face between the front and rear ends of the sleeve through hole, thereby limiting / positioning the workpiece sleeve.

[0016] Preferably, in the above-mentioned case, the diameter of the rear section of the sleeve through hole is not greater than the diameter of the rear end hole of the workpiece sleeve.

[0017] Preferably, in the above case, the rear end of the sleeve through hole is provided with a chamfered structure, or in other words, the rear end is a tapered (frustum-shaped) opening / flared opening, to facilitate the insertion of slender parts.

[0018] Preferably, the workpiece sleeve is a metal tube with the required rigidity to prevent bending during grinding. For example, the workpiece sleeve is a capillary tube made of metal.

[0019] Preferably, the workpiece clamping device includes a pressure plate and a clamping screw (stud or bolt). The clamping screw is perpendicular to the base plate. The front end of the clamping screw is connected (fixed connection or axial limiting connection) to the base plate. The pressure plate is sleeved on the clamping screw through the screw through hole on the pressure plate. The rear end of the clamping screw protrudes from the rear side of the pressure plate and is screwed (threaded connection) with a clamping nut.

[0020] Preferably, there can be two clamping screws located on both sides (both sides of the pressure plate and the base plate) to facilitate balance.

[0021] The clamping nut can be a wing nut for ease of operation.

[0022] Preferably, an elastic pad, such as a rubber pad, is placed between the clamping nut and the pressure plate to prevent the clamping nut from loosening during operation.

[0023] The rubber pad or other elastic pad can be in the form of a washer, which is fitted onto the clamping screw.

[0024] Preferably, the workpiece clamping device includes a pressure plate and a pressure plate guide rod. The pressure plate guide rod is perpendicular to the base plate, and its front end is fixed on the base plate. The pressure plate is sleeved on the pressure plate guide rod through a guide hole or guide sleeve on the pressure plate. The guide hole or guide sleeve is slidably engaged with the pressure plate guide rod, allowing the pressure plate to slide along the guide rod direction and preventing it from wobbling on the guide rod. The rear end of the pressure plate guide rod protrudes from the rear side of the pressure plate and is provided with a pressure plate limiting structure (e.g., a baffle that can block the pressure plate from moving further backward). A tension spring (e.g., a pre-stretched helical spring) is sleeved on the pressure plate guide rod. The front end of the tension spring is connected to the base plate, and the rear end is connected to the pressure plate, pulling the pressure plate towards the base plate, thereby pressing the pressure plate tightly against the rear end of the workpiece protruding from the rear end of the sleeve through hole.

[0025] Preferably, there are two pressure plate guide rods located on both sides to facilitate balance.

[0026] Preferably, the pressure plate is a V-shaped plate, or in other words, it adopts a V-groove structure with a rearward convex V-shape in cross-section. When the pressure plate is pressed against the rear end of the workpiece, the rear end of the workpiece is located in the V-groove, thereby automatically achieving centering and stability and preventing the pressure plate from tilting or the rear end of the workpiece from slipping.

[0027] Furthermore, this multi-workpiece synchronous grinding equipment is provided with a frame (or bed), on which a spindle system (or grinding wheel system) and a feed system (or workpiece system) are provided. The spindle system includes a spindle motor and a grinding wheel shaft. The spindle motor is connected to the grinding wheel shaft via a belt drive mechanism (or other form of spindle drive mechanism). A cylindrical grinding wheel is provided on the grinding wheel shaft. The feed system includes a linear feed mechanism. The driven component (output component, for example, feed frame) of the linear feed mechanism is a transverse (perpendicular to the feed direction) feed frame. A support plate is provided on the feed frame, and a clamping device for clamping the workpiece fixture is provided on the support plate.

[0028] The support plate is connected to the feed frame via a fixed connector or in any other suitable direction.

[0029] Preferably, the support plate is connected to the feed frame via an angle adjustment mechanism to adjust the grinding angle of the cutting edge.

[0030] Preferably, the support plate has jaws at both ends for clamping workpieces and clamping plates for pressing the clamped part onto the jaws.

[0031] The beneficial effects of this invention are as follows: Since the workpiece sleeve / capillary tube is ground together with the workpiece, the slender workpiece remains within the capillary tube throughout the grinding process. Supported by the capillary tube, bending of the workpiece during grinding is avoided or significantly reduced, thus improving grinding quality. The capillary tube is threaded onto the substrate, making replacement convenient. Commercially available or other existing products can be used for the capillary tube, resulting in low cost. The presence of a pressure plate pressing against the rear end of the workpiece, which clamps the workpiece via threads, ensures strict synchronization between the workpiece and the capillary tube during grinding, preventing the workpiece from moving backward due to grinding pressure. It enables grinding of the front end of the workpiece; since multiple sets of capillaries and workpieces can be assembled in the same fixture, and grinding is carried out using a cylindrical grinding wheel shaft, multiple workpieces can be ground synchronously at the same time, which greatly improves the processing efficiency; since a linear feed mechanism is used to implement the linear feed of the fixture, and an angle adjustment mechanism is used to adjust the grinding angle of the workpiece, the grinding angle and grinding speed can be controlled according to the process requirements, which is suitable for different workpiece cutting edge grinding requirements. Compared with existing ordinary and special-purpose grinding machines, it significantly simplifies the structure of the grinding machine and tooling, facilitates operation or control, and helps to reduce system errors. Attached Figure Description

[0032] Figure 1 This is a schematic diagram (front view) of the workpiece fixture involved in the present invention; Figure 2 This is a schematic diagram (side view) of the workpiece fixture involved in the present invention; Figure 3 This is a schematic diagram (front view) of the capillary tube involved in the present invention. Figure 4 This is a schematic diagram (front view) of the grinding machine involved in the present invention; Figure 5 This is a schematic diagram (top view) of the grinding machine involved in the present invention; Figure 6 This is a schematic diagram of the grinding motor and its connection with the belt drive mechanism involved in the present invention; Figure 7 This is a schematic diagram of the grinding wheel shaft involved in the present invention; Figure 8 This is a schematic diagram of the clamp operating mechanism involved in the present invention. Figure 9 This is a schematic diagram (left view) of the grinding machine involved in the present invention. Detailed Implementation

[0033] See Figures 1-9The workpiece fixture mainly consists of a pressure plate 24, a base plate 21, and several workpiece sleeves 22 for fixing the workpiece. The workpiece sleeves can be made of thin metal tubes with the required rigidity, such as commercially available capillary tubes, whose diameter is adapted to the main body of the workpiece (slender part), allowing the main body of the workpiece to be manually inserted and pulled out. The workpiece sleeves fix the inserted workpiece by the constraint of the tube holes, preventing it from shaking or moving eccentrically.

[0034] The main body of the slender component is elongated (e.g., a long cylinder) with a cutting edge at the front end. The rear part (e.g., the handle of a needle knife) 13 is thicker than the main body and cannot be inserted into a workpiece sleeve. The diameter of the workpiece sleeve (e.g., a capillary tube) is adapted to the main body of the slender component, allowing it to be inserted and removed. The gap between the two should be minimized to avoid eccentricity or wobbling of the main body of the slender component within the tube, which could affect the machining quality. In this case, the gap can be referred to as zero gap or near-zero gap.

[0035] Multiple workpiece sleeves are set on the same fixture so that multiple workpieces can be ground simultaneously in the same operation.

[0036] Since the workpiece sleeve is ground together with the workpiece, the workpiece sleeve needs to be replaced. The rear end (with external thread) 27 of the workpiece sleeve is screwed (threaded connection) onto the threaded through hole of the base plate for easy installation and removal.

[0037] The rear end of the workpiece sleeve is chamfered and has a small conical (frustum-shaped) opening (or trumpet-shaped opening) to facilitate workpiece insertion. The cone angle β can be about 90°.

[0038] The pressure plate adopts a V-shaped groove structure with the front middle part concave backward. When it presses on the rear end of the workpiece, the rear end of the workpiece automatically centers to the center of the V-shaped groove and is in a stable state, thereby avoiding the rear end of the workpiece from shifting or slipping due to factors such as the tilting of the pressure plate.

[0039] Two (or more) clamping screws (studs) 23 can be set to connect the pressure plate and the base plate. The rear part of the workpiece is clamped between the pressure plate and the base plate. Tightening the clamping nut 26 located on the rear side of the pressure plate will clamp the workpiece. The rear part of the thicker workpiece will be pressed and stuck into the rear end of the threaded through hole on the base plate or the rear end of the workpiece sleeve (depending on the relative thickness of the rear part of the workpiece and the screw through hole), thereby fixing the workpiece.

[0040] Before tightening the clamping nut, first put the rubber washer (washer 25) on the screw. After tightening the clamping nut, the rubber washer located between the clamping nut and the pressure plate will be deformed by pressure to prevent the clamping nut from loosening due to vibration during operation.

[0041] The clamping screw can be a stud, a single-ended bolt, or any other suitable rod that can be threaded with the clamping nut. Any suitable technology can be used to connect the lower end of the screw to the base plate. This connection can be a fixed connection (e.g., welding) or a limiting connection (preventing the screw from being pulled back from the base plate). For example, the head of the single-ended bolt is placed on the front side of the base plate, and a flared opening conforming to the bolt head can be provided at the front end of the through hole on the base plate for receiving the bolt head and limiting the rotation of the bolt.

[0042] The grinding wheel 35 in the grinding machine is cylindrical with shaft extensions at both ends for mounting bearings (both ends) and the driven wheel 34 (one end) of the belt drive mechanism 33, which can be called the grinding wheel shaft. The spindle motor 32 drives the grinding wheel shaft to rotate through the belt drive mechanism. The feed direction of the feed mechanism is perpendicular to the axis of the grinding wheel shaft, and the axial direction of each workpiece sleeve is also perpendicular to (opposite plane perpendicular) the axis of the grinding wheel shaft. Thus, the grinding progress can be controlled by the feed mechanism to realize the synchronous grinding of multiple workpieces (and workpiece sleeves on the workpieces) on the workpiece fixture.

[0043] The linear feed mechanism includes a feed frame 37 that serves as the output component, and the feed frame moves linearly. The linear feed mechanism can employ any linear motion mechanism, such as a linear guide mechanism with a corresponding drive motor. In a preferred embodiment, the linear feed mechanism may include two parallel longitudinal (along the feed direction) guide rods (e.g., cylindrical shafts) 36 and a feed frame (or beam) 37 perpendicular to the guide rods. The guide rods are fixedly mounted on the frame (table) 31 via guide rod supports. The feed frame is located above the guide rods, with bearing seats 38 positioned below them on both sides, and auxiliary components such as positioning screws 39 for positioning the bearing seats. Linear bearings that mate with the corresponding side guide rods are mounted on the bearing seats, thereby achieving a longitudinal movement connection between the feed frame and the guide rods. The feed frame can be driven by existing technology or any other suitable technology. For example, a screw and nut mechanism and a feed motor for driving the screw can be set up. The nut of the screw and nut mechanism is fixedly installed on the feed frame, and the screw is rotatably installed on the frame and driven by the feed motor. The feed motor drives the screw to rotate, and then drives the feed frame to move through the nut. Alternatively, a feed cylinder / pneumatic cylinder for driving the feed frame to move can be set on the frame.

[0044] An angle adjustment mechanism is installed on the feed frame, which drives the support plate 41 to move, thereby adjusting the posture / angle of the support plate. For example, an angle adjustment shaft 47 is rotatably connected to the feed frame via a bearing, and an angle adjustment motor is installed on the feed frame to drive the rotation of the angle adjustment shaft. The support plate is fixedly connected to the angle adjustment shaft via a connector (connecting plate) 43, thereby enabling the angle control and adjustment of the support plate through the angle adjustment motor.

[0045] The jaws at both ends of the support plate extend forward from the support plate. Each jaw has a limiting step for engaging the corresponding side edge of the base plate (the base plate of the workpiece fixture). The L-shaped structures of the two limiting steps face each other, and the clamping plate 42 is located outside the limiting steps and is fixed to the corresponding jaws by clamping plate screws. In use, the two side edges of the workpiece fixture base plate are placed within the L-shaped structure, fitting against its surface. The clamping plate is pressed against the outside of the base plate edges and secured with clamping plate screws, thus clamping the two side edges of the base plate between the corresponding limiting steps and the clamping plate. After the workpiece fixture is installed in place, the pressure plate is located in the space between the two jaws. The length of the pressure plate should usually be less than the length of the base plate and be able to cover / press the entire workpiece sleeve to fit the space between the two jaws. The workpiece sleeve extends forward, and the rotation angle of the rotating shaft is adjusted according to the angle to tilt downward at the corresponding angle towards the grinding wheel shaft. The height of the grinding wheel shaft is lower than the height of the feed frame. Through the feeding movement of the feed frame, the front end of the workpiece sleeve and the workpiece contacts the grinding surface of the grinding wheel shaft to perform grinding at the corresponding angle.

[0046] Unless otherwise specified, the preferred and optional technical means disclosed in this invention can be arbitrarily combined to form several different specific embodiments when one preferred or optional technical means is a further limitation of another technical means.

Claims

1. A method for grinding slender parts, characterized in that... The main body of the slender part is fixedly inserted into the workpiece sleeve. According to the grinding requirements of the slender part, the workpiece sleeve and the slender part fixed together are ground together. Multiple workpiece sleeves are set on the same workpiece fixture. The main body of multiple slender parts are inserted into different workpiece sleeves respectively. The same workpiece clamping device is used to clamp each slender part from the rear end to the front. The tail of the slender part is stuck outside the rear end of the workpiece sleeve. The workpiece sleeves and slender parts fixed together on the workpiece fixture are ground together. A cylindrical grinding wheel shaft is used to perform synchronous grinding of the workpiece sleeves and slender parts on the same fixture.

2. The grinding method for slender parts as described in claim 1, characterized in that... The grinding angle is controlled or adjusted according to the grinding requirements of slender parts.

3. The grinding method for slender parts as described in claim 1, characterized in that... The workpiece fixture has a base plate, and the workpiece sleeve is located on the front side of the base plate and arranged parallel to each other on the same plane. The base plate has a sleeve through hole for installing the workpiece sleeve. The rear end of the workpiece sleeve is detachably connected to the sleeve through hole of the base plate. The rear side of the base plate has a workpiece clamping device for pressing the rear end of the workpiece forward.

4. The grinding method for slender parts as described in claim 3, characterized in that... The sleeve through hole is provided with an internal thread to form a threaded through hole, and the rear part of the workpiece sleeve is provided with an external thread to be threadedly connected to the sleeve through hole, thereby realizing the detachable connection of the rear end of the workpiece sleeve on the substrate.

5. The grinding method for slender parts as described in claim 3, characterized in that... The sleeve through hole is a stepped hole, divided into front and rear sections. Both the front and rear sections are holes of equal diameter, with the diameter of the front section being larger than that of the rear section and adapted to the outer diameter of the workpiece sleeve. The rear section of the workpiece sleeve is inserted into the front section of the sleeve through hole and fits tightly with the sleeve through hole, thereby realizing the detachable connection of the rear section of the workpiece sleeve on the substrate.

6. The grinding method for slender parts as described in any one of claims 3-5, characterized in that... The workpiece sleeve is a metal tube with the required rigidity.

7. The grinding method for slender parts as described in any one of claims 3-5, characterized in that... The workpiece clamping device includes a pressure plate and a clamping screw. The clamping screw is perpendicular to the base plate. The front end of the clamping screw is connected to the base plate. The pressure plate is fitted onto the clamping screw through a screw through hole on the pressure plate. The rear end of the clamping screw protrudes from the rear side of the pressure plate and is screwed with a clamping nut.

8. The grinding method for slender parts as described in any one of claims 3-5, characterized in that... The workpiece clamping device includes a pressure plate and a pressure plate guide rod. The pressure plate guide rod is perpendicular to the base plate, and its front end is fixed on the base plate. The pressure plate is sleeved on the pressure plate guide rod through a guide hole or guide sleeve on the pressure plate. The guide hole or guide sleeve is slidably engaged with the pressure plate guide rod. The rear end of the pressure plate guide rod protrudes from the rear side of the pressure plate and is provided with a pressure plate limiting structure. A tension spring is sleeved on the pressure plate guide rod. The front end of the tension spring is connected to the base plate, and the rear end is connected to the pressure plate.

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