Pull cord encoder with customizable limit points

Abstract

The application provides a pull rope encoder with customizable limit points, and belongs to the technical field of pull rope encoders.The pull rope encoder comprises a winding assembly, a winding wheel arranged in a shell, and a pull rope wound on the winding wheel; the measuring assembly comprises a measuring wheel arranged in the shell, the free end of the pull rope passes through a limit switch, winds around the measuring wheel, passes through another limit switch, and then extends out of the shell through a wire outlet to connect a connector, the connector is used for connecting a target object to be measured; the rotating shaft of the measuring wheel is connected with a rotary encoder; each limit switch corresponds to a limit switch measuring point, the limit switch measuring point has magnetism and can be clamped on the pull rope to move with the pull rope.The application avoids multiple winding, thereby solving the stacking error; the limit points and zero points are provided, the integration degree is increased, the matching parts, the occupied space, and the cost of the limit points and zero points are reduced; the integrated limit points and zero points are installed after the pull rope encoder is installed, the zero points and the limit points are set, the flexibility is higher, and the adjustment is facilitated.

Description

Technical Field

[0001] This invention relates to the field of draw rope encoder technology, and more specifically to a draw rope encoder with customizable limit points. Background Technology

[0002] A draw-wire encoder, also known as a draw-wire displacement sensor, draw-wire sensor, draw-wire electronic ruler, etc., combines the advantages of angle sensors and linear displacement sensors. It is a linear displacement sensor with a compact structure, long measuring stroke, high measurement accuracy, reliable performance, and low cost.

[0003] Draw-wire encoders are mainly used in linear guide systems, hydraulic cylinder systems, telescopic systems, hollow blow molding machines, IT equipment, tension regulation, high-speed automatic feeders, speed regulation, warehouse positioning, pressure machinery, papermaking machinery, textile machinery, metal sheet machinery, paper packaging machinery, printing machinery, level controllers, construction machinery, gate opening measurement, and other related dimensional measurement and position control applications. They are also widely used in screen display and digital display systems in the testing machine industry, and their prospects are very promising.

[0004] A draw-wire encoder detects and measures linear position and speed using a flexible draw-wire and a spring-loaded spool. It mainly consists of four parts: a measuring wire, a spool, a spring, and a rotary sensor. Its working principle is as follows: Inside the sensor housing, a stainless steel draw-wire is wound around a precision-machined straight cylindrical spool, which serves as both a measuring wire spool and an unwinding spool. To maintain the draw-wire tension, a spring is coupled to the spool. The spool is then coupled to the shaft of a rotary sensor (encoder or potentiometer). As the sensor's draw-wire extends along a movable object, the spool and sensor shaft rotate. The rotating shaft generates an electronic signal proportional to the linear extension or speed of the draw-wire.

[0005] Currently, most pull-cord encoders on the market use a design where the encoder's rotating shaft and the winding reel are coaxial. Because the winding reel is wider than the wire rope, irregular layering of the wire rope occurs on the reel. As the number of coils increases, the winding radius fluctuates, affecting the winding circumference and leading to measurement errors. Due to the long measuring stroke and large number of coils in pull-cord encoders, they are generally configured as incremental encoders rather than absolute encoders. Therefore, they typically require the use of zero-position and limit switches, increasing the complexity of the equipment. Summary of the Invention

[0006] The purpose of this invention is to provide a pull-cord encoder with customizable limit points to solve at least one of the technical problems existing in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a drawstring encoder with customizable limit points, comprising:

[0009] A cable winding assembly, comprising a winding reel disposed within a housing, on which a pull rope is wound;

[0010] The measuring assembly includes a measuring wheel housed within a housing. The free end of a pull rope passes through a limit switch, then around the measuring wheel, and after passing through another limit switch, extends out from the cable outlet on the housing to connect to a connector. The connector is used to connect to the target object to be measured. A rotary encoder is connected to the shaft of the measuring wheel.

[0011] Each limit switch corresponds to a limit switch measuring point. The limit switch measuring point is magnetic and can be clamped onto the pull rope and move with the pull rope.

[0012] Preferably, the limit switch measuring point is a magnetic ring with an opening and an inward elasticity, through which the pull rope passes; the limit switch is located on the housing and can move on the housing along the direction of the pull rope; a release plug is movably inserted into the housing wall, one end of the release plug is inserted into the opening to open the magnetic ring so that the pull rope passes through the magnetic ring.

[0013] Preferably, the winding assembly further includes a deformation element. When the rope is pulled out, the winding wheel rotates, causing the deformation element to deform and store energy. When the connector is separated from the target object, the deformation element returns to its original shape, causing the winding wheel to rotate in the opposite direction to retract the rope.

[0014] Preferably, a winding assembly box is provided on the outer wall of the housing, the deformable member is disposed in the winding assembly box, the shaft of the winding reel can be movably passed through the wall of the housing and extended into the winding assembly box, and is connected to one end of the deformable member, and the other end of the deformable member is connected to the winding assembly box.

[0015] Preferably, the rotary encoder is disposed on the outer wall of the housing, and the shaft of the measuring wheel rotatably passes through the housing and is connected to the rotary encoder.

[0016] Preferably, the pull rope passes around the measuring wheel, then around the first guide wheel, then around the second guide wheel, passes through the magnetic ring, extends out of the outer casing through the outlet, and connects to the connector.

[0017] Preferably, the outer casing is provided with a limiting hole, and the limiting switch is disposed in the limiting hole and can slide within the limiting hole.

[0018] Preferably, the measuring wheel is provided with a winding groove, and the winding groove is provided with anti-slip rubber material.

[0019] Preferably, the outer casing is provided with a through hole through which the release plug moves, and one end of the release plug extending into the outer casing is a support rod, the end of which is inserted into the opening of the magnetic ring.

[0020] Preferably, the limit switch is a Hall effect proximity switch.

[0021] The beneficial effects of this invention are as follows: Using a driven layer measurement method avoids multiple turns of winding, thus solving the layering error problem; the multi-turn measurement of the pull-cord encoder determines its incremental rather than absolute measurement method, therefore, the assistance of zero-point and limit points is almost unavoidable; the built-in zero-point and limit points increase integration and reduce the supporting components, space occupation, and cost of the zero-point and limit points; the integrated zero-point and limit points can be set in actual working conditions, and the zero-point and limit points are set after the pull-cord encoder is installed, resulting in greater flexibility and easier adjustment.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, 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.

[0024] Figure 1 This is a front view of the drawstring encoder with customizable limit points as described in an embodiment of the present invention.

[0025] Figure 2 This is a structural diagram of the back of a pull-cord encoder with customizable limit points as described in an embodiment of the present invention.

[0026] Figure 3 This is a diagram of the internal structure of a drawstring encoder with customizable limit points as described in an embodiment of the present invention.

[0027] Figure 4 This is a structural diagram of the fine-tuning limit switch and the limit switch measuring point of the pull-rope encoder with customizable limit points, as described in an embodiment of the present invention.

[0028] Figure 5 This is a diagram illustrating the one-time release structure of the limit switch measuring point of the pull-rope encoder with customizable limit points, as described in an embodiment of the present invention.

[0029] The pull-cord encoder with customizable limit points is characterized by comprising:

[0030] Cable winding assembly: 1-Housing; 2-Winding reel; 3-Pull rope; 4-Measuring wheel; 5-Limit switch; 6-Cable outlet; 7-Connector; 8-Rotary encoder; 9-Limit switch measuring point; 10-Opening; 11-Release plug; 12-Cable winding assembly box; 13-First guide wheel; 14-Second guide wheel; 15-Limit hole; 16-Winding groove; 17-Support rod. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0034] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0035] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0036] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In the description of this specification, the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this technology and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this technology.

[0038] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of these terms in this art according to the specific circumstances.

[0039] To facilitate understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0040] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0041] like Figures 1 to 5 As shown, this embodiment provides a pull-cord encoder with customizable limit points, including: a winding assembly, which includes a winding wheel 2 disposed inside a housing 1, on which a pull-cord 3 is wound; a measuring assembly, which includes a measuring wheel 4 disposed inside the housing 1, the free end of the pull-cord 3 passing through a limit switch 5, then around the measuring wheel 4, and then through another limit switch 5, extending out from the outlet 6 on the housing 1 to connect to a connector 7, the connector 7 being used to connect to the target object to be measured; a rotary encoder 8 is connected to the shaft of the measuring wheel 4; each limit switch 5 corresponds to a limit switch measuring point 9, the limit switch measuring point 9 being magnetic and able to be clamped onto the pull-cord 3 and move with the pull-cord.

[0042] Specifically, the limit switch measuring point 9 is a magnetic ring with an opening 10 and an inward elasticity, through which the pull rope 3 passes; the limit switch 5 is located on the housing 1 and can move along the direction of the pull rope on the housing 1; a release plug 11 is movably inserted into the housing wall, one end of the release plug 11 is inserted into the opening 10 to open the magnetic ring so that the pull rope 3 passes through the magnetic ring.

[0043] The winding assembly also includes a deformation element. When the rope 3 is pulled out, the winding wheel 2 rotates, causing the deformation element to deform and store energy. When the connector 7 is separated from the target object, the deformation element returns to its original shape, causing the winding wheel 2 to rotate in the opposite direction to retract the rope 3.

[0044] The outer wall of the housing 1 is provided with a winding assembly box 12. The deformable member is disposed in the winding assembly box 12. The shaft of the winding wheel 2 can be movably passed through the wall of the housing and extended into the winding assembly box 12, and is connected to one end of the deformable member. The other end of the deformable member is connected to the winding assembly box 12.

[0045] In one specific embodiment, the deformable element may be a planar spiral spring.

[0046] Mounting holes are provided on the wall of the outer casing, and bearings are installed in the mounting holes. The outer ring of the bearing is fixedly connected to the wall of the mounting hole. The shaft of the winding reel 2 passes through the inner ring of the bearing, extends out of the outer casing, and connects to a planar spiral spring inside the winding assembly box 12. The other end of the planar spiral spring is connected to the winding assembly box 12. The connector 7 is connected to the target object to be tested. After the target object moves and pulls out the rope, the winding reel 2 drives the planar spiral spring to deform and store energy. When the connector detaches from the target object or the target object approaches the winding reel 2, the planar spiral spring releases energy, driving the winding reel 2 to rotate in the opposite direction and retract the rope.

[0047] The rotary encoder 8 is mounted on the outer wall of the housing 1. The shaft of the measuring wheel 4 rotatably passes through the housing and is connected to the rotary encoder 8. Similarly, a bearing mounting hole is provided on the outer wall of the housing 1, and a bearing is installed in the bearing mounting hole. The shaft of the measuring wheel 4 passes through the bearing and is connected to the rotary encoder 8. Pulling out or retracting the rope drives the measuring wheel 4 to rotate, and the rotation of the measuring wheel 4 drives the rotary encoder to rotate, thereby achieving distance measurement.

[0048] The pull rope 1 passes around the measuring wheel 4, then around the first guide wheel 13, then around the second guide wheel 14, passes through the limit switch measuring point 9, and extends out of the outer shell through the outlet 6 to connect with the connector 7.

[0049] The housing is provided with a limiting hole 15, and the limiting switch 5 is disposed in the limiting hole 15 and can slide within the limiting hole 15. The limiting switch 5 is a Hall proximity switch.

[0050] The measuring wheel 4 is provided with a winding groove 16, and the winding groove 16 is filled with anti-slip rubber material. This ensures the friction performance between the pull rope and the measuring wheel 4, and ensures that the measuring wheel 4 can rotate stably and reliably with the pull rope.

[0051] The outer casing 1 has a through hole through which the release bolt 11 moves. One end of the release bolt 11 extends into the outer casing 1 and serves as a support rod 17. The end of the support rod 17 is inserted into the opening 10 of the magnetic ring, causing the magnetic ring to open and allowing the pull rope to pass through it. When the release bolt is pulled out, the support rod 17 disengages from the opening, and the magnetic ring has an inward elastic force, thereby gripping the pull rope tightly.

[0052] The measuring wheel 4 of the measuring assembly is a driven wheel, always winding no more than one full turn of the pull rope 1. The winding assembly has a winding wheel 2 and a deformation element that cooperate to automatically reset, retract, and wind multiple turns of the pull rope. It has one or more non-contact limit switches 5, through which the pull rope passes. Along the pulling direction of the pull rope, the upper limit switch is located between the winding wheel 2 and the measuring wheel 4, and the zero-point switch or lower limit switch is located between the measuring wheel 4 and the outlet 6. The measuring wheel 4 is relatively narrow, which can limit the axial transmission on the measuring wheel 4 during the pulling process of the pull rope, thereby reducing measurement errors. Auxiliary pulleys (such as the first guide wheel and the second guide wheel) can be installed before and after the measuring wheel to increase the wrap angle of the pull rope on the measuring wheel and improve friction performance. Near the limit switches, there is a non-contact limit switch measuring point 9 that is sleeved on the pull rope and mounted on the housing, which can be released once from outside the pull rope encoder and is clamped on the pull rope after release. This is used for coarse adjustment of the limit point on-site according to the working conditions after encoder installation. The limit switch can slide and be fixed within a small range along the pulling direction of the pull rope, and can be operated externally by the encoder for fine adjustment of the limit point. The limit switch can use a Hall effect proximity switch; the limit switch measuring point is made of magnetic material.

[0053] The method for releasing the limit switch measuring point is as follows: a C-shaped limit switch measuring point (i.e., a magnetic ring with an opening) with inward elasticity is supported by a release bolt and fitted onto the pull rope. When the release bolt is pulled out from the outside of the pull rope encoder, the C-shaped limit switch measuring point tightens inward and is fixed to the pull rope.

[0054] Specifically, in one embodiment, the winding assembly consists of a winding reel and a planar spiral spring fixed coaxially therewith. The spiral spring stores energy when the winding reel 2 unwinds the wire, and releases energy when the winding reel 2 winds up the wire. The winding assembly box 12 encapsulates the spiral spring and other components on the front of the rope encoder.

[0055] The measuring assembly consists of a measuring wheel 4 and a rotary encoder 8 fixed coaxially therewith. The measuring wheel 4 has a wire rope groove (i.e., a winding groove 16) with high dimensional accuracy and a rubber material with good friction performance on its surface to increase the friction between the pull rope and the measuring wheel, ensuring that the pull rope can stably and reliably pull the measuring wheel to rotate.

[0056] One end of the pull rope is fixed to the winding reel 2, and passes sequentially through the extended limit switch measuring point 9, the measuring wheel 4, the auxiliary pulleys (first guide wheel and second guide wheel), and another extended limit switch measuring point 9 before extending out of the pull rope encoder housing. The other end is fixed to the wire rope end mounting piece (i.e., the connector). Each extended limit switch measuring point 9 is supported by a release bolt 11 installed on the back of the pull rope encoder, ensuring a fixed position and not obstructing the winding and unwinding of the wire rope. On the other side of the extended limit switch measuring point 9, there is a sliding and fixed limit switch 5, whose position can be adjusted from the front of the pull rope encoder.

[0057] In practical use, the cable encoder housing is installed at one end of the target to be measured, and the wire rope end fitting is fixed to the other end of the target. To move or extend the target, near the minimum distance, pull out the upper limit switch release plug located between the winding reel and the measuring reel, releasing the limit switch measuring point onto the wire rope. Then, fine-tune the limit position by sliding the upper limit switch. Near the maximum distance, pull out the lower limit switch release plug located between the measuring reel and the cable outlet, releasing the limit switch measuring point onto the wire rope. Finally, fine-tune the limit position by sliding the lower limit switch.

[0058] In actual operation, the movement or extension of the target being measured is driven by the wire rope end mounting, which in turn drives the measuring wheel to rotate, ultimately rotating the rotary encoder. The upper and lower limit switches integrated into the pull-rope encoder provide limit or zero positions for the target's movement or extension, eliminating the need for separate installation locations. Furthermore, the ability to define the limit switch measuring points on-site offers greater flexibility in the design and debugging of the movement or extension mechanism. Since the travel of the upper limit switch measuring point is between the upper limit switch and the winding wheel, and the travel of the lower limit switch measuring point is outside the lower limit switch and the pull-rope encoder housing, neither point passes through the measuring wheel. Only half a turn of wire rope is always on the measuring wheel, ensuring a stable linear relationship between the rotary encoder's rotation angle and the wire rope's winding length, thus avoiding measurement errors caused by wire rope stacking or shifting.

[0059] In summary, the draw-wire encoder with customizable limit points described in this embodiment of the invention features a separately designed measuring wheel to utilize a driven measurement method, thus avoiding multiple turns of winding. Simultaneously, a tensioning wheel prevents slippage between the wire rope and the measuring wheel, resolving winding overlap errors. The multi-turn measurement of the draw-wire encoder dictates its incremental rather than absolute measurement method, thus almost inevitably requiring the assistance of zero-point and limit points. By installing measuring points on the wire rope and utilizing non-contact sensors for detection, zero-point and limit points are integrated within a limited sensor space, making the draw-wire encoder more functional and its overall structure more compact. The design of releasing the measuring points onto the wire rope during installation allows for setting the zero-point and limit points after the draw-wire encoder is installed, increasing flexibility and convenience while reducing the design burden caused by the uncertain trigger position of ordinary limit sensors.

[0060] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A drawstring encoder with customizable limit points, characterized in that, include: The winding assembly includes a winding reel (2) disposed inside the housing (1), and a pull rope (3) is wound on the winding reel (2). The measuring component includes a measuring wheel (4) located inside the housing (1). The free end of the pull rope (3) passes through a limit switch (5) and then passes around the measuring wheel (4). After passing through another limit switch (5), it extends out of the cable outlet (6) on the housing (1) to the connector (7). The connector (7) is used to connect to the target object to be measured. The shaft of the measuring wheel (4) is connected to a rotary encoder (8). Each limit switch (5) corresponds to a limit switch measuring point (9). The limit switch measuring point (9) is magnetic and can be clamped on the pull rope (3) and move with the pull rope. The limit switch measuring point (9) is a magnetic ring with an opening (10) and an inward elasticity. The pull rope (3) passes through the magnetic ring. The limit switch (5) is located on the housing (1) and can move on the housing (1) along the direction of the pull rope. A release plug (11) is movably inserted into the housing wall. One end of the release plug (11) is inserted into the opening (10) to open the magnetic ring so that the pull rope (3) passes through the magnetic ring. The winding assembly also includes a deformation element. When the rope (3) is pulled out, the winding wheel (2) rotates and causes the deformation element to deform and store energy. When the connector (7) is separated from the target object, the deformation element returns to its original state and causes the winding wheel (2) to rotate in the opposite direction to retract the rope (3).

2. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The outer wall of the housing (1) is provided with a winding assembly box (12), the deformable element is disposed in the winding assembly box (12), the shaft of the winding wheel (2) can be moved through the wall of the housing and extend into the winding assembly box (12), and is connected to one end of the deformable element, and the other end of the deformable element is connected to the winding assembly box (12).

3. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The rotary encoder (8) is located on the outer wall of the housing (1), and the shaft of the measuring wheel (4) is rotatably connected to the rotary encoder (8) after passing through the housing.

4. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The pull rope passes around the measuring wheel (4), then around the first guide wheel (13), then around the second guide wheel (14), passes through the limit switch measuring point (9), and extends out of the outer shell through the outlet (6) to connect with the connector (7).

5. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The outer shell is provided with a limiting hole (15), and the limiting switch (5) is located in the limiting hole (15) and can slide within the limiting hole (15).

6. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The measuring wheel (4) is provided with a winding groove (16), and the winding groove (16) is provided with anti-slip rubber material.

7. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The outer shell (1) is provided with a through hole through which the release plug (11) moves. One end of the release plug (11) extending into the outer shell (1) is a support rod (17), and the end of the support rod (17) is inserted into the opening (10) of the magnetic ring.

8. The drawstring encoder with customizable limit points according to claim 1, characterized in that, The limit switch (5) is a Hall proximity switch.

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