Femoral stem deflection angle visual inspection tool and inspection method thereof

Abstract

Provided is a visual inspection tool for the deflection angle of a femoral stem and a method for detecting the same, comprising a front mold and a rear mold with a vertically inserted cavity; a vertically inserted positioning surface is provided on the right side of the cavity, and a first guide pin and a second guide pin are provided at the bottom of the left side of the cavity, which are tangent to the left side of the femoral body of a standard forging; the deflection angle λ° of the detection line inclined to the lower right determined by the first and second guide pins is the same as the deflection angle β° of the standard forging; after the standard forging slides into the cavity by gravity, its cone tip is exposed from the exposure port below the cavity; and the horizontal width of the cavity insertion port is exactly equal to the horizontal width of the widest part of the intertrochanteric crest of the standard forging; the forging to be tested whose cone tip of the femoral body is exposed from below the exposure port is a qualified forging, otherwise it is an unqualified forging. The present invention detects whether the forging is qualified or not by inserting and placing a free fall body and then visually inspecting whether the cone tip is exposed from the bottom, which can meet the needs of large-scale and efficient detection of forgings, without the assistance of a vernier caliper, and the detection is simple, convenient, economical, efficient and practical.

Description

Technical Field

[0001] The invention belongs to the technical field of measuring and checking tools for physical irregular surfaces, and in particular relates to a visual checking tool for the deflection angle of a femoral stem and a detection method thereof. Background Art

[0002] The titanium alloy femoral stem is an important component of the artificial hip joint system, in which the femoral stem must be forged to obtain good mechanical properties and tissue stability. However, during the forging process, the internal stress of the femoral stem forging is affected by the sudden change in temperature inside and outside the forging. During the rapid cooling of the forging surface, its internal thermal stress can easily cause the forging to warp and deform to varying degrees, resulting in an excessive deviation angle of the forging. In order to obtain femoral stem forging products with consistent deviation angle quality, the current method for measuring the deviation angle of the femoral stem forging is the traditional three-coordinate measurement, which is inefficient and not suitable for large-scale testing. In this regard, although the announcement number CN209197631U discloses a cross-sectional width gauge for the femoral stem of a hip prosthesis, it only detects the cross-sectional width of the femoral stem; it cannot meet the large-scale rapid and efficient detection requirements of the deviation angle β° of the femoral head of the femoral stem relative to the vertical femoral body, and directly visually inspects whether the femoral stem meets the design requirements without using any precision gauges such as vernier calipers. In this regard, the following technical solution is proposed. Summary of the invention

[0003] The technical problem solved by the present invention is as follows: A visual inspection tool for the runout angle of a femoral stem and a method for detecting the same are provided, so as to solve the problem in the prior art that the femoral stem forging shrinks upon cooling and is easily warped and deformed due to thermal stress, resulting in an excessive runout angle of the femoral stem forging, and there is a lack of a technical problem in the prior art that a large number of pass or fail inspections of the runout angle of the femoral stem forgings can be quickly carried out by visual inspection only without using a vernier caliper.

[0004] The technical solution adopted by the present invention: a visual inspection tool for the deflection angle of the femoral stem, characterized in that it includes a front mold and a rear mold symmetrically distributed about the front and rear axes relative to the vertical plane; the front and rear molds are fastened together to form an insertion inspection tool with a vertical long channel penetration structure; a mold body composed of the front and rear molds has a vertical insertion cavity symmetrical about the front and rear axes; the right side of the insertion cavity has a vertical insertion positioning surface; the vertical insertion positioning surface is used to vertically straighten the forging from the right side of the forging to ensure the vertical insertion of the forging in the cavity; and cooperates with the vertical insertion positioning surface; a first guide pin and a second guide pin are provided at the bottom of the rear mold cavity; the first guide pin and the second guide pin are horizontally installed perpendicular to the vertical planes of the front and rear mold bodies; the outer cylindrical surfaces of the first guide pin and the second guide pin are tangent to the left side of the femoral body of the standard forging when it is vertically inserted in the cavity; and when the standard forging is inserted in the cavity by relying on the free fall of the forging gravity, the cone tip of the standard forging is exposed from below the exposure port; the first and second guide pins are located in the cavity according to the principle of determining a straight line by two points A detection line is formed in the middle part and tilted toward the lower right side of the cavity; the deflection angle λ° of the detection line relative to the vertical direction is the same as the deflection angle β° of the femoral head relative to the vertical femoral body when the standard forging is vertically inserted in the cavity; and the top of the cavity is the insertion port for the vertical insertion of the forging, and the bottom of the cavity is the conical tip exposure port at the bottom end of the femoral body of the forging; the insertion port and the exposure port are both rectangular structures and the horizontal width of the insertion port is greater than the horizontal width of the exposure port; the forging to be tested falls freely from the insertion port to the bottom of the cavity by the forging's own gravity. The forging to be tested shall be qualified if the tip of the femoral body of the forging to be tested is exposed from below the exposure port, and the lower end of the femoral body of the standard forging is completely vertically slid into the inspection cavity; the lower end of the femoral body of the standard forging is exposed from below the exposure port; and the horizontal width of the insertion port at the top of the cavity is exactly equal to the horizontal width of the widest part of the intertrochanteric ridge of the standard forging; when the forging to be tested slides into the cavity by free fall due to the gravity of the forging; the forging to be tested whose tip of the femoral body is exposed from below the exposure port is qualified; the forging to be tested whose tip of the femoral body is not exposed from the exposure port is unqualified.

[0005] Furthermore: In order to facilitate the use of the front and rear molds to realize the detection of femoral stem forgings with different bending angles: the first guide pin and the second guide pin are respectively detachably fixed at the bottom of the rear mold through several pairs of mounting holes coaxial with the guide pins; the center line of each pair of mounting holes is inclined toward the lower right side of the cavity to form multiple detection lines at different angles.

[0006] The detection method using the visual detection tool for the femoral stem deflection angle described in any of the above technical solutions comprises the following steps:

[0007] Step 1, select the front die and the rear die and assemble them: the first and second guide pins installed at the bottom of the front die and the rear die determine a detection line inclined toward the lower right side of the cavity in the cavity according to the principle that two points determine a straight line; the deflection angle λ° of the detection line relative to the vertical direction is the same as the deflection angle β° of the femoral head relative to the vertical femoral body when the standard forging is vertically inserted in the cavity;

[0008] Step 2: Place the femoral stem yaw angle visual inspection tool upright: visually compare the horizontal widths of the insertion port and the exposure port, place the end with the larger horizontal width upwards and the end with the smaller horizontal width downwards, and hold the femoral stem yaw angle visual inspection tool upright with one hand;

[0009] Step 3, inserting the forging to be tested: hold the forging to be tested with the other hand, and insert the femoral body cone tip of the forging to be tested from the top insertion port of the upright inspection fixture cavity, and the forging to be tested will slide to the bottom of the cavity by free fall due to its own gravity; the forging to be tested whose femoral body cone tip is exposed from below the exposure port is a qualified forging; the forging to be tested whose femoral body cone tip cannot be exposed from the exposure port and is stuck in the cavity is an unqualified forging; and the horizontal width of the widest part of the intertrochanteric ridge of the qualified forging to be tested is just stuck at the top insertion port of the cavity.

[0010] Compared with the prior art, the present invention can achieve the following effects:

[0011] 1. This solution is small in size, has high detection efficiency, does not require high machining accuracy for the front and rear mold cavities, has excellent reliability, has small error in the detection of the deflection angle accuracy, is practical and durable, does not require high technical skills for the inspectors, and can meet the needs of large-scale and efficient detection;

[0012] 2. The guide pins of this scheme can be detachably fixed and installed at the bottom of the rear mold by wedging, threaded connection, etc.; the detection line 7 of the inspection fixture can adjust and replace the installation positions of the first and second guide pins at any time according to the change of the deflection angle β of the forging to be tested, thereby adaptively changing the deflection angle of the left detection line 7 in the cavity of the inspection fixture; realize the adaptive adjustment and replacement detection needs of a set of mold bodies to meet the standard forgings with different deflection angles; one thing has multiple uses; economical and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A front view showing the use of the inspection tool of the present invention to inspect a standard forging;

[0014] Figure 2 for Figure 1 AA section view;

[0015] Figure 3 For the present invention Figure 1 A top view of the insertion port;

[0016] Figure 4 for Figure 3 A BB cross-sectional view of a detection line 7 defined by two points of the first and second guide pins;

[0017] Figure 5 For the present invention Figure 1 Stereogram;

[0018] Figure 6 for Figure 4Schematic diagram of the first and second guide pins installed at the bottom of the rear mold to determine the detection line 7;

[0019] Figure 7 Standard forgings (femoral stem) and Figure 6 Schematic diagram of the deflection angle detection principle matched with the rear mold cavity detection principle;

[0020] Figure 8 for Figure 5 In the middle is a stereoscopic view of the front and rear molds after assembly;

[0021] Fig. 9 The present invention is a schematic diagram of a plurality of pairs of first and second guide pin mounting holes formed in a rear mold cavity that can form different detection lines. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-9 Describe the specific embodiments of the present invention. It is worth to understand that the embodiments described below are only exemplary, and not specific limitations of the present invention.

[0023] The following examples are provided to facilitate a better understanding of the present invention, but are not intended to limit the present invention. The insertion and forging methods in the following examples are conventional methods. The components and materials used in the following examples are commercially available unless otherwise specified.

[0024] In the present invention, unless otherwise stated, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only simplified descriptions for the convenience of describing the present invention, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "set", and "provided with" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an indirect connection through other intermediate components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The visual inspection tool for the deflection angle of the femoral stem is characterized by comprising a front mold 1 and a rear mold 2 symmetrically distributed relative to the front and rear axes of the vertical plane (see Figure 1 , Figure 2 , Figure 8); the front and rear molds (1, 2) are fastened together by hexagon socket head screws to realize disassembly or assembly, and form a vertical long channel penetration structure insertion and placement inspection fixture; it should be noted that: the front and rear molds (1, 2) are symmetrically distributed in the front and rear axes (see Figure 2 ): First, it is conducive to reducing the difficulty of mold processing; because during processing, it is only necessary to ensure the straightness of the vertical right wall of the cavity 3 of the long channel structure when the front and rear molds (1, 2) are closed to meet the positioning requirements of the forging 4 being vertically inserted in the cavity 3; and such process and structural requirements, compared with the use of special-shaped cavity inspection fixtures that match standard forgings, have lower requirements on the dimensional accuracy of the mold; therefore, it is conducive to reducing the mold manufacturing cost. On this basis, the front and rear molds (1, 2) mentioned above are fastened together by fasteners at the front and rear, which facilitates the assembly or disassembly of the front and rear molds (1, 2); it is conducive to the installation or replacement of the first and second guide pins (5, 6) mentioned later, that is, to achieve the adjustment of the swing angle of the first and second guide pins (5, 6) mentioned later. On this basis, regarding the adjustment of the yaw angle detected by the first and second guide pins (5, 6), it should be noted that: the first and second guide pins (5, 6) detect whether the angle formed between the intertrochanteric ridge of the forging 4 and the femoral stem is qualified based on the principle of two points determining a straight line; regarding the term "intertrochanteric ridge", it should be noted that: "intertrochanteric ridge" is a professional naming term for the corresponding part of the femoral stem, and "intertrochanteric ridge" usually refers to the junction between the trochanter of the femoral stem and the femoral body 4-4 (such as Figure 7 As shown). The right vertical side wall of the long channel cavity 3 is a vertical reference line, which is used to vertically position the forging 4; the left side of the cavity is connected by the first and second guide pins 5 and 6 to establish the detection line 7 as described later. That is, the mold body composed of the front and rear molds (1, 2) has a vertical insertion cavity 3 symmetrical with the front and rear axes; the right side of the insertion cavity 3 has a vertical insertion positioning surface 3-3; the vertical insertion positioning surface 3-3 is used to vertically straighten the forging 4 from the right side of the forging 4 to ensure the vertical insertion of the forging 4 in the cavity 3; cooperate with the vertical insertion positioning surface 3-3; the first guide pin 5 and the second guide pin 6 are provided at the bottom of the rear mold 2; the first guide pin 5 and the second guide pin 6 are perpendicular to the front and rear molds (1, 2) (as shown Figure 4 The outer cylindrical surface of the first guide pin 5 and the second guide pin 6 is tangent to the left side of the femoral body 4-2 of the standard forging 4 when it is vertically inserted in the cavity 3 (see Figure 4 ); and when the standard forging 4 is inserted into the cavity by free fall due to the gravity of the forging, the cone tip 4-3 of the standard forging 4 is exposed from below the exposure opening 3-2; the first guide pin 5 and the second guide pin 6 form a detection line 7 (such as the detection line 7) in the middle of the cavity 3 that is inclined toward the lower right side of the cavity 3 according to the principle that two points determine a straight line. Figure 6); the deflection angle λ of the detection line 7 relative to the vertical direction is the same as the deflection angle β° of the femoral head 4-1 relative to the vertical femoral body 4-2 when the standard forging 4 is vertically inserted into the cavity 3 (see Figure 4 , Figure 6 , Figure 7 ); and the top of the cavity 3 is the insertion opening 3-1 for the vertical insertion of the forging 4, and the bottom of the cavity 3 is the exposure opening 3-2 of the cone tip 4-3 at the bottom end of the femoral body of the forging 4; the insertion opening 3-1 and the exposure opening 3-2 are both rectangular structures (see Figure 3 , Figure 8 ) and the horizontal width of the insertion opening 3-1 is greater than the horizontal width of the exposure opening 3-2 (see Figure 4 , Figure 6 , Fig. 9 ), so that by visually comparing the sizes of the insertion port 3-1 and the exposure port 3-2, it is possible to quickly distinguish which is the upper end of the inspection fixture and which is the lower end of the inspection fixture. The forging to be tested slides from the insertion port 3-1 to the bottom of the cavity 3 by free fall of the forging 4 itself under its own gravity, and the middle part between the intertrochanteric ridge of the standard forging 4 and the bottom end of the femoral body slides completely vertically into the inspection cavity 3; it should be noted that: the term "intertrochanteric ridge" is a professional nomenclature for the corresponding part of the femoral stem, and the "intertrochanteric ridge" usually refers to the junction between the trochanter of the femoral stem and the femoral body 4-4 (such as Figure 7 As shown). The bottom end of the femoral body of the standard forging 4 is exposed from below the exposure opening 3-2; and the horizontal width of the insertion opening 3-1 at the top of the long channel type cavity 3 is just equal to the horizontal width of the widest part of the intertrochanteric crest of the standard forging 4; when the forging to be tested slides into the cavity by free fall due to the gravity of the forging; the forging to be tested whose femoral body cone tip 4-3 is exposed from below the exposure opening 3-2 is a qualified forging; the forging to be tested whose femoral body cone tip 4-3 is not exposed from the exposure opening 3-2 is an unqualified forging.

[0027] In the above embodiment, further: the first guide pin 5 and the second guide pin 6 are respectively connected through a plurality of pairs of mounting holes 5-1 (such as Fig. 9 The center line of each pair of mounting holes 5-1 is tilted toward the lower right of the cavity 3 to form a plurality of detection lines 7 at different angles. It should be noted that: Fig. 9 The multiple mounting holes 5-1 shown correspond to three groups of different angles of the detection line 7 deflection angle; that is, the detection lines 7 corresponding to the degrees of λ1°, λ2°, and λ3°, respectively. The straight detection line 7 determined by two points of each pair of mounting holes 5-1, respectively corresponds to the mounting holes 5-1 of the required detection line 7, and the first and second guide pins (5, 6) are screwed or wedged into the fixed installation. Thereby meeting the needs of batch, efficient, and scale-free visual inspection of the forgings to be tested with the deflection angle of the femoral head of the detection line 7 to determine whether it is qualified or not. Usually, the deflection angles λ1°, λ2°, and λ3° are between 35° and 45°.

[0028] In the above embodiment, further: in order to facilitate the use of the front and rear molds (1, 2) to detect femoral stem forgings with different bending angles: the detection method using the femoral stem deflection angle visual inspection tool described in the above embodiment is characterized by comprising the following steps:

[0029] Step 1: Select front mold 1 and rear mold 2 and assemble them (such as Figure 6 ): The first guide pin 5 and the second guide pin 6 installed at the bottom of the front mold 1 and the rear mold 2 determine a detection line 7 inclined toward the lower right of the cavity 3 in the cavity 3 according to the principle that two points determine a straight line; the deflection angle λ° of the detection line 7 relative to the vertical direction is the same as the deflection angle β° of the femoral head 4-1 relative to the vertical femoral body 4-2 when the standard forging 4 is vertically inserted in the cavity 3. That is, according to the deflection angle β° of the standard forging, select a suitable detection line 7 and install the pins, then assemble the front and rear molds (1, 2);

[0030] Step 2: Place the femoral stem bending linearity visual inspection tool (such as Figure 8 ): Visually compare the horizontal widths of the insertion opening 3-1 and the exposure opening 3-2, with the end with the larger horizontal width, i.e. the insertion opening 3-1, facing upwards, and the end with the smaller horizontal width, i.e. the exposure opening 3-2, facing downwards, and hold the femoral stem runout angle visual inspection tool in one hand after being placed upright;

[0031] Step 3: Insert the forging to be tested (such as Figure 5 ): Hold the forging to be tested with the other hand, and insert the femoral cone tip of the forging to be tested from the top insertion port 3-1 of the upright inspection fixture cavity 3. The forging to be tested slides to the bottom of the cavity 3 by free fall due to its own gravity. The forging to be tested whose femoral cone tip 4-3 is exposed below the exposure port 3-2 is a qualified forging (such as Figure 4 ); the femoral body cone tip 4-3 of the forging to be tested cannot be exposed from the exposure port 3-2, and the forging to be tested is stuck in the cavity, which is an unqualified forging; and the horizontal width of the widest part of the intertrochanteric ridge of the qualified forging to be tested is just stuck at the insertion port 3-1 at the top of the cavity 3 (such as Figure 4 ). It should be emphasized that even if the femoral body cone tip 4-3 of a part of the forging to be tested can be exposed from the exposure opening 3-2, but at the same time as the femoral body cone tip 4-3 can be exposed from the exposure opening 3-2, if the horizontal width of the widest part of the intertrochanteric ridge of the forging to be tested is located above the insertion opening 3-1 at the top of the cavity 3, it is still an unqualified forging, which means that although the forging to be tested also slides into the cavity, its swing angle still deviates from the swing angle of the standard forging. Therefore, visually judging whether the forging to be tested is a qualified forging must meet two conditions at the same time: one condition is that the cone tip 4-3 at the bottom end of the forging to be tested can be exposed from the exposure opening 3-2; the other condition is that the horizontal width of the widest part of the intertrochanteric ridge of the forging to be tested is just stuck at the insertion opening 3-1 at the top of the cavity 3 (such as Figure 4 ). Neither is indispensable.

[0032] Working principle: the front die 1 and the rear die 2 are fastened together by hexagon socket head screws; the front and rear dies 1 and 2 have an insertion cavity 3 for detecting whether the swing angle of the femoral stem forging meets the requirements; the insertion cavity 3 guides the vertical insertion of the detection forging along the vertical insertion positioning surface 3-3 on the right side of the cavity; the first guide pin 5 and the second guide pin 6 provided on the left side of the insertion cavity 3 determine a detection line 7 inclined to the lower right according to the principle that two points determine a straight line; the forging to be tested relies on the forging The free fall of the forging itself slides into the cavity 3 from the insertion port 3-1; only the femoral body cone tip of the forging to be tested, whose swing angle is the same as the swing angle β° of the standard forging and the swing angle λ° of the detection line 7, can be exposed from the bottom exposure port 3-2 of the inspection fixture; not only that, the naked eye can also directly observe that the horizontal width of the widest part of the top inter-ridge of the forging to be tested exposed from the bottom exposure port 3-2 of the inspection fixture is just stuck at the insertion port 3-1 at the top of the cavity 3, indicating that the swing angle of the forging to be tested meets the standard design requirements. When the swing angle of the forging to be tested deviates from the swing angle β° of the standard forging and the swing angle λ° of the detection line 7, the forging to be tested will inevitably be stuck in the cavity 3 and cannot slide down smoothly. On the one hand, the femoral body cone tip of the forging to be tested cannot be exposed from the exposure port 3-2. Even if it is exposed a little, as long as the widest part of the top inter-ridge of the forging to be tested is elevated above the insertion port 3-1, it means that the swing angle of the forging to be tested does not meet the design requirements.

[0033] Compared with the prior art: the present invention designs a method that does not require the use of any precision measuring fixtures such as vernier calipers to assist in detection, but directly performs a simple loosening and inserting operation. The inspector only needs to observe with the naked eye whether the bottom end of the femoral body cone tip of the forging to be tested can be exposed from the exposure port 3-2 at the bottom end of the inspection fixture, and at the same time, if the horizontal width of the widest part of the top inter-ridge of the forging to be tested is just stuck at the insertion port 3-1 at the top of the cavity 3, it indicates that the forging is a qualified forging; otherwise, it is an unqualified forging. Compared with the mold design with the authorization announcement number CN209197631U, which still needs to use precision inspection tools such as vernier calipers to complete the detection, the detection can be completed by visual inspection, which can greatly improve the detection efficiency, and is particularly suitable for large-scale and efficient detection of femoral stem forgings with a fixed swing angle of β°. In addition, the swing angle λ° of the detection line 7 can also be adjusted by replacing the first and second guide pins (5, 6) at different mounting positions of the mounting holes 5-1.

[0034] Through the above description, it can be found that: the present invention is small in size; efficient in detection; low in machining accuracy requirements for the front and rear mold cavities; excellent in reliability; small in error in detection of the swing angle accuracy; practical and durable; low in technical requirements for inspectors; and can meet the needs of large-scale efficient detection. In addition, the guide pins of this scheme can be detachably fixed and installed at the bottom of the rear mold by wedging, threaded connection, etc.; the detection line 7 of the inspection fixture can adjust and replace the installation positions of the first and second guide pins 5 and 6 at any time according to the change in the swing angle β of the forging to be tested, thereby adaptively changing the swing angle of the left detection line 7 in the cavity of the inspection fixture; realizing a set of molds to adapt to the adaptive adjustment and replacement detection needs of standard forgings with different swing angles; one thing has multiple uses; economical and practical.

[0035] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0036] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0037] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, all equivalent changes made to the contents described in the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A visual inspection tool for the deflection angle of the femoral stem, characterized by: The invention comprises a front die (1) and a rear die (2) which are symmetrically distributed with respect to the front and rear axes of a vertical plane; the front and rear dies (1, 2) are fastened together to form an insertion and placement inspection fixture with a vertical long channel penetration structure; a die body formed by the front and rear dies (1, 2) has a vertical insertion and placement cavity (3) which is symmetrical with respect to the front and rear axes; the right side of the insertion and placement cavity (3) has a vertical insertion and placement positioning surface (3-3); the vertical insertion and placement positioning surface (3-3) is used to vertically straighten the forging (4) from the right side of the forging (4) to ensure the vertical insertion and placement of the forging (4) in the cavity (3); and cooperates with the vertical insertion and placement positioning surface (3-3); a cavity body of the cavity (3) is provided with a vertical insertion and placement positioning surface (3-3); A first guide pin (5) and a second guide pin (6) are provided at the bottom; the first guide pin (5) and the second guide pin (6) are installed horizontally perpendicular to the vertical planes of the front and rear mold bodies (1, 2); the outer cylindrical surfaces of the first guide pin (5) and the second guide pin (6) are tangent to the left side of the femoral body (4-2) of the standard forging (4) when the femur is vertically inserted in the cavity (3); the first guide pin (5) and the second guide pin (6) form a detection line (7) inclined toward the lower right of the cavity (3) in the middle of the cavity (3) based on the principle of determining a straight line by two points; the detection line (7) deflects toward the lower right relative to the vertical direction. The angle λ° is the same as the deflection angle β° of the femoral head (4-1) relative to the vertical femoral body (4-2) when the standard forging (4) is vertically inserted in the cavity (3); the top of the cavity (3) is an insertion opening (3-1) for the forging (4) to be vertically inserted, and the bottom of the cavity (3) is an exposure opening (3-2) of the cone tip (4-3) at the bottom end of the femoral body of the forging (4); the insertion opening (3-1) and the exposure opening (3-2) are both rectangular structures, and the horizontal width of the insertion opening (3-1) is greater than the horizontal width of the exposure opening (3-2); the forging to be tested slides from the insertion opening (3-1) to the bottom of the cavity (3) by free fall due to the weight of the forging (4) itself. The middle part between the intertrochanteric crest and the bottom end of the femur of the standard forging (4) completely slides vertically into the detection cavity (3); the bottom end of the femur of the standard forging (4) is exposed from below the exposure opening (3-2); and the horizontal width of the insertion opening (3-1) at the top of the long channel cavity (3) is exactly equal to the horizontal width of the widest part of the intertrochanteric crest of the standard forging (4); when the forging to be tested slides into the cavity by free fall due to the gravity of the forging; the forging to be tested whose femur cone tip (4-3) is exposed from below the exposure opening (3-2) is a qualified forging; and the forging to be tested whose femur cone tip (4-3) is not exposed from the exposure opening (3-2) is an unqualified forging.

2. The visual inspection tool for the femoral stem runout angle according to claim 1, characterized in that: The first guide pin (5) and the second guide pin (6) are detachably fixedly mounted on the bottom of the rear mold (2) of the cavity (3) through a plurality of pairs of mounting holes (5-1) coaxial with the guide pins; the center connecting line of each pair of mounting holes (5-1) is inclined toward the lower right of the cavity (3) to form a plurality of detection lines (7) at different angles.

3. A detection method using the visual inspection tool for femoral stem deflection angle according to claim 1 or 2, characterized in that: The steps include: Step 1, selecting a front mold (1) and a rear mold (2) and assembling them: the first guide pin (5) and the second guide pin (6) installed at the bottom of the front mold (1) and the rear mold (2) determine a detection line (7) inclined toward the lower right of the cavity (3) in the cavity (3) according to the principle that two points determine a straight line; the deflection angle λ° of the detection line (7) relative to the vertical direction is the same as the deflection angle β° of the femoral head (4-1) relative to the vertical femoral body (4-2) when the standard forging (4) is vertically inserted in the cavity (3); Step 2: Place the femoral stem yaw angle visual inspection tool upright: visually compare the horizontal widths of the insertion opening (3-1) and the exposure opening (3-2), place the end with the larger horizontal width upwards and the end with the smaller horizontal width downwards, and hold the femoral stem yaw angle visual inspection tool upright with one hand; Step 3, inserting the forging to be tested: holding the forging to be tested with the other hand, inserting the femoral body cone tip of the forging to be tested from the top insertion port (3-1) of the upright inspection fixture cavity (3), and the forging to be tested slides to the bottom of the cavity (3) by free fall due to the forging's own gravity; the forging to be tested whose femoral body cone tip (4-3) is exposed from below the exposure port (3-2) is a qualified forging; the forging to be tested whose femoral body cone tip (4-3) cannot be exposed from the exposure port (3-2) and is stuck in the cavity is an unqualified forging; and the horizontal width of the widest part of the intertrochanteric ridge of the qualified forging to be tested is just stuck at the top insertion port (3-1) of the cavity (3).

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