Patent Publication Number: US-2023151828-A1

Title: Telescopic actuator, actuating system and motion simulating apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to Taiwan patent application no. 110142226 filed on Nov. 12, 2021. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to telescopic actuators, in particular to telescopic actuators suitable for use with actuating systems and motion simulating apparatuses. 
     2. Description of the Related Art 
     Telescopic actuators are suitable for use in environments having a limited space. Conventionally, a telescopic actuator includes multiple movable cylinders, wherein an intermediate cylinder can extend along with a preceding cylinder until the intermediate cylinder contacts against a next cylinder and consequently stops. Conversely, when retracting, the preceding cylinder first comes in contact with the intermediate cylinder and then urges the intermediate cylinder to retract. 
     In practice, the conventional telescopic actuator may provide an output force that exceeds an expected output during operation, and the collision occurring between cylinders may produce undesirable vibration and noise and cause structural damages. In order to reduce vibration and noise, a conventional approach consists in adding springs to absorb the collision energy. However, the added springs cannot totally eliminate the collision between cylinders, and still cannot address the issue of excessive output forces during operation. 
     Therefore, there is a need for a construction that can address at least the aforementioned issues. 
     SUMMARY 
     The present application describes a telescopic actuator and an actuating system that can address at least the foregoing issues, and a motion simulating apparatus incorporating the telescopic actuator. 
     According to one embodiment, a telescopic actuator includes a first segment having a first hollow cavity, a second segment having a second hollow cavity, a third segment having a third hollow cavity, and a first and a second port. The second segment is slidably connected to the first segment through the first hollow cavity, and the third segment is slidably connected to the second segment through the second hollow cavity, the second hollow cavity being insulated from the first hollow cavity and communicating with the third hollow cavity. The first port is configured to flow fluid into and out of the first hollow cavity, and the second port is configured to flow fluid into and out of the second hollow cavity and the third hollow cavity. 
     According to one embodiment, a motion simulating apparatus includes a support base, an occupant platform adapted to carry one or more occupants, and the telescopic actuator, wherein the first segment of the telescopic actuator is connected to the support base, and the third segment of the telescopic actuator is connected to the occupant platform. 
     According to one embodiment, an actuating system includes a telescopic actuator and a pressure source. The telescopic actuator includes a plurality of telescopic segments, a first port and a second port, wherein the telescopic segments at least include a first segment having a first hollow cavity, and a second segment having a second hollow cavity, the second segment being slidably connected to the first segment through the first hollow cavity and the first and second hollow cavities being insulated from each other, the first port being configured to flow fluid into and out of the first hollow cavity, and the second port being configured to flow fluid into and out of the second hollow cavity. The pressure source is respectively connected to the first port and the second port via a first conduit and a second conduit. The second segment has an end that is located inside the first hollow cavity and has a first end surface and a second end surface facing opposite directions, the first end surface being configured to contact with a fluid inside the first hollow cavity, the second end surface being configured to contact with a fluid inside the second hollow cavity, and the pressure source being operable to create different fluid pressures in the first hollow cavity and the second hollow cavity so that the second segment is in a floating state and is movable in an extending direction in a stop-and-go manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view illustrating an embodiment of a telescopic actuator; 
         FIG.  2    is a perspective view illustrating the telescopic actuator of  FIG.  1    under another angle of view; 
         FIG.  3    is a cross-sectional view of the telescopic actuator shown in  FIG.  1   ; 
         FIG.  4    is a schematic view illustrating an embodiment of an actuating system; and 
         FIG.  5    is a schematic view illustrating an embodiment of a motion simulating apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIGS.  1  and  2    are perspective views illustrating an embodiment of a telescopic actuator  100  under different angles of view, and  FIG.  3    is a cross-sectional view illustrating the telescopic actuator  100 . Referring to  FIGS.  1 - 3   , the telescopic actuator  100  includes three stages or segments  102 ,  104  and  106 , and a plurality of ports  110  and  112 . Each of the segments  102 ,  104  and  106  can be formed as a tubular rod having a hollow interior. The segments  102 ,  104  and  106  are slidably connected to one another so that the segments  104  and  106  can slide along a lengthwise axis X of the telescopic actuator  100  relative to the segment  102  for extending outward and retracting inward. The telescopic actuator  100  is actuated by flowing a fluid therein, wherein a fluid can flow into and/or out of the segments  102 ,  104  and  106  through the ports  110  and  112  during the telescopic movement of the segments  104  and  106 . For example, a fluid can be flowed through the ports  110  and  112  into the segments  102 ,  104  and  106  to cause extension of the segments  104  and  106 . When the segments  104  and  106  retract owing to the application of an external force that is greater than an opposite force resulting from an inner fluid pressure, fluid can flow through the ports  110  and  112  out of the segments  102 ,  104  and  106 . 
     Referring to  FIGS.  1 - 3   , the segment  102  has a hollow cavity  116  that extends between two opposite ends  102 A and  102 B of the segment  102  and is at least partially delimited by a sidewall  102 C of the segment  102 . The sidewall  102 C extends along the lengthwise axis X, and is connected to the two ends  102 A and  102 B of the segment  102 . The segment  104  has a hollow cavity  118  that extends between two opposite ends  104 A and  104 B of the segment  104  and is at least partially delimited by a sidewall  104 C of the segment  104 . The sidewall  104 C extends along the lengthwise axis X, and is connected to the two ends  104 A and  104 B of the segment  104 . The segment  106  has a hollow cavity  120  that extends between two opposite ends  106 A and  106 B of the segment  106  and is at least partially delimited by a sidewall  106 C of the segment  106 . The sidewall  106 C extends along the lengthwise axis X, and is connected to the two ends  106 A and  106 B of the segment  106 . 
     The segment  104  is slidably connected to the segment  102  through the hollow cavity  116  with the end  104 A of the segment  104  disposed inside the hollow cavity  116  between the two ends  102 A and  102 B of the segment  102 , the end  104 B of the segment  104  extending outward from the end  102 B of the segment  102 . The segment  104  can thereby slide along the lengthwise axis X relative to the segment  102  for retracting into or extending outside the segment  102  at the end  102 B thereof. The course of the segment  104  relative to the segment  102  can be delimited by the two ends  102 A and  102 B of the segment  102 , wherein a greatest extending length of the segment  104  relative to the segment  102  can correspond to a state where the end  104 A of the segment  104  is located adjacent to the end  102 B of the segment  102 . 
     The segment  106  is slidably connected to the segment  104  through the hollow cavity  118  with the end  106 A of the segment  106  disposed inside the hollow cavity  118  between the two ends  104 A and  104 B of the segment  104 , the end  106 B of the segment  106  extending outward from the end  104 B of the segment  104 . The segment  106  can thereby slide along the lengthwise axis X relative to the segments  102  and  104  for retracting into or extending outside the segment  104  at the end  104 B thereof. The course of the segment  106  relative to the segment  104  can be delimited by the two ends  104 A and  104 B of the segment  104 , wherein a greatest extending length of the segment  106  relative to the segment  104  can correspond to a state where the end  106 A of the segment  106  is located adjacent to the end  104 B of the segment  104 . 
     Within the telescopic actuator  100 , the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106  communicate with each other and form a connected cavity so that a fluid fed into any of the hollow cavities  118  and  120  can create a substantially equal pressure therein. For example, the end  106 A of the segment  106  inside the hollow cavity  118  can have an opening  122  through which the hollow cavity  120  of the segment  106  can communicate with the hollow cavity  118  of the segment  104 . Moreover, the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106  are insulated from the hollow cavity  116  of the segment  102  so that no fluid flows between the hollow cavity  116  and the hollow cavities  118  and  120 . Accordingly, a fluid can be respectively flowed into the hollow cavity  116  and the connected cavity formed by the hollow cavities  118  and  120  to create different pressures therein. 
     According to an embodiment, the hollow cavity  118  of the segment  104  can be insulated from the hollow cavity  116  of the segment  102  so that no fluid flows between the hollow cavity  116  and the hollow cavity  118 . For example, the end  104 A and the sidewall  104 C of the segment  104  inside the hollow cavity  116  of the segment  102  can insulate the hollow cavity  118  of the segment  104  from the hollow cavity  116  of the segment  102  so that the hollow cavity  116  of the segment  102  does not communicate with the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106 . Accordingly, fluid can be respectively flowed into the connected cavity of the hollow cavities  118  and  120  and a space inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  to create different pressures therein. 
     According to an example of construction, the end  104 A of the segment  104  can have a circumference provided with a fluid seal  123  configured to insulate the space inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  from the space inside the hollow cavity  116  between the end  102 B of the segment  102  and the end  104 A of the segment  104 , whereby fluid flowing between the two insulated spaces can be prevented. 
     According to another example of construction, the fluid seal  123  may be omitted, and limited fluid flowing may be allowed between the space inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  and the space inside the hollow cavity  116  between the end  102 B of the segment  102  and the end  104 A of the segment  104 . 
     Referring to  FIGS.  1 - 3   , the port  110  can communicate with the hollow cavity  116  of the segment  102  so that a fluid can flow through the port  110  into and out of the hollow cavity  116 . According to an example of construction, the port  110  is provided on the segment  102 . For example, the port  110  can be placed on the end  102 A of the segment  102 , and can communicate with the hollow cavity  116  via a channel  124  provided inside the end  102 A of the segment  102 . A fluid can thereby flow through the port  110  and the channel  124  into and out of the space that is located inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104 . 
     The port  112  can communicate with the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106  so that a fluid can flow through the port  112  into and out of the hollow cavities  118  and  120 . According to an example of construction, the port  112  can be provided on the segment  102  and can be connected to a flowing tube  126  disposed inside the segment  102 , whereby a fluid can flow through the port  112  and the flowing tube  126  into and out of the hollow cavities  118  and  120 . For example, the end  104 A of the segment  104  can have an opening  128 , and the flowing tube  126  can be connected to the end  102 A of the segment  102  inside the hollow cavity  116  thereof and extend through the opening  128  on the end  104 A of the segment  104  into the hollow cavity  118 . The port  112  can be placed on the end  102 A of the segment  102 , and can be connected to the flowing tube  126  via a channel  130  provided inside the end  102 A of the segment  102 . The port  112 , the channel  130  and the flowing tube  126  can thereby communicate with one another. The flowing tube  126  extends along the lengthwise axis X, and has a length configured to accommodate a greatest extension of the segment  104  relative to the segment  102 . According to an example of construction, the flowing tube  126  can extend along the lengthwise axis X inside the hollow cavity  116  of the segment  102 , through the opening  128  on the end  104 A into the hollow cavity  118  of the segment  104 , and through the opening  122  on the end  106 A into the hollow cavity  120  of the segment  106 . 
     According to an example of construction, the end  104 A of the segment  104  can have a fluid seal  132  disposed adjacent to the opening  128 . The fluid seal  132  can be disposed around a circumference of the flowing tube  126  so as to prevent fluid flowing through the opening  128  between the hollow cavity  116  of the segment  102  and the hollow cavity  118  of the segment  104 . The space inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  can be thereby insulated from the hollow cavity  118  of the segment  104 . 
     Within the telescopic actuator  100 , the end  104 A of the segment  104  is located inside the hollow cavity  116  of the segment  102  and has two end surfaces  134  and  136  facing opposite directions. The end surface  134  is configured to contact with a fluid inside the hollow cavity  116 , the end surface  136  is configured to contact with a fluid inside the hollow cavity  118 , and the end surface  134  can have a surface area greater than that of the end surface  136 . Moreover, the end  106 B of the segment  106  has an end surface  138  that faces the end  104 A of the segment  104  and is configured to contact with a fluid inside the hollow cavity  120 , the end surface  136  having a surface area greater than that of the end surface  138 . 
     With the aforementioned construction, a fluid may be flowed into the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  to create a fluid pressure P 1  therein, and a fluid can be flowed into the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106  to create a fluid pressure P 2  therein that can differ from the fluid pressure P 1 . During operation, the hollow cavity  116  of the segment  102  thus can receive a fluid that contacts with the end surface  134  and creates a buffer pressure, which can result in a pushing force applied on the end surface  134  that tends to offset an opposite force applied on the end surface  136  owing to a fluid pressure inside the hollow cavities  118  and  120 . Accordingly, the segment  104  may be configured to be in a floating state relative to the segments  102  and  106  during extending and retracting movements along the lengthwise axis X, which can prevent excessive impact of the segment  104  against the segments  102  and  106  that could produce undesirable vibration and noise. 
     According to some embodiments, the telescopic actuator  100  is powered by compressed gas, and the ports  110  and  112  are gas ports. According to other embodiments, the telescopic actuator  100  is powered by gas and liquid, one of the ports  110  and  112  being a gas port configured to receive the passage of compressed gas, and the other one of the ports  110  and  112  being a liquid port configured to receive the passage of liquid. According to some other variant embodiments, the telescopic actuator  100  is powered by liquid, and the ports  110  and  112  are liquid ports. 
     According to the needs, the telescopic actuator  100  may include additional ports configured to flow fluids during operation of the segments  104  and  106 . For example, the segment  102  may have a port  140  disposed adjacent to the end  102 B, as shown in  FIG.  3   . The port  140  is spaced apart from the ports  110  and  112  along the lengthwise axis X, and communicates with a space inside the hollow cavity  116  between the end  102 B of the segment  102  and the end  104 A of the segment  104 . The end  104 A of the segment  104  can slide within the hollow cavity  116  of the segment  102  between the two ports  110  and  140 , wherein a fluid outflow can occur through the port  140  while a fluid inflow occurs through the ports  110  and  112 , and a fluid inflow can occur through the port  140  while a fluid outflow occurs through the ports  110  and  112 . 
     In conjunction with  FIGS.  1 - 3   ,  FIG.  4    is a schematic view illustrating an embodiment of an actuating system  150 . Referring to  FIGS.  1 - 4   , the actuating system  150  includes the telescopic actuator  100  and a pressure source  152 . The pressure source  152  is connected to the port  110  of the telescopic actuator  100  via a conduit  154 , and is connected to the port  112  of the telescopic actuator  100  via a conduit  156 . During operation, one or more fluid supplied by the pressure source  152  can be flowed through the conduits  154  and  156  into and out of the telescopic actuator  100 . The pressure source  152  can be any passive pressure sources suitable to apply a fluid pressure. According to a pressure value to maintain corresponding to a load need of the telescopic actuator  100 , a passive pressure source may passively react to a stress variation and induce fluid inflow/outflow. For example, the pressure source  152  can include at least two pressure accumulators  152 A and  152 B respectively connected to the conduits  154  and  156 , whereby the fluids supplied by the pressure accumulators  152 A and  152 B can be respectively flowed through the conduits  154  and  156  into the telescopic actuator  100 . 
     According to an embodiment, the pressure source  152  can supply compressed gas, and the pressure accumulators  152 A and  152 B can be gas pressure accumulators. It will be appreciated, however, that the pressure source  152  is not limited to this specific example. The pressure accumulators  152 A and  152 B may also be liquid pressure accumulators to form a liquid pressure source, or gas and liquid pressure accumulators to form a hybrid pressure source. 
     The pressure source  152  can include one or more pressure control valve so that a same fluid pressure or different fluid pressures can be provided at the output of the pressure source  152 . Moreover, the pressure source  152  can include one or more flow control/directional control valves for controlling the flow speed/direction through the conduits  154  and  156 . According to an embodiment, fluid can flow through the conduits  154  and  156  with a same flow speed. According to another embodiment, fluid can flow through the conduits  154  and  156  with different flow speeds. 
     For extending the telescopic actuator  100 , the pressure accumulators  152 A and  152 B of the pressure source  152  can be operated so that a fluid is flowed into the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  to create a fluid pressure P 1  therein, and a fluid is flowed into the hollow cavity  118  of the segment  104  and the hollow cavity  120  of the segment  106  to create a fluid pressure P 2  therein, wherein the fluid pressure P 1  can differ from the fluid pressure P 2 . The fluid pressure P 2  can result in a force F 1  applied on the end surface  138  of the segment  106  in an extending direction, which causes the segment  106  to slide relative to the segments  102  and  104  in the extending direction. Moreover, the fluid pressure P 2  can also create an opposing force F 2  applied on the end surface  136  of the segment  104  in a retracting direction opposite to the extending direction. By adjusting the fluid pressure P 1 , a resulting pushing force F 3  applied on the end surface  134  of the segment  104  in the extending direction can tend to offset the opposing force F 2  so that the segment  104  can temporarily remain stationary during operation. 
     While the opposing force F 2  and the pushing force F 3  are approximately equal to each other, the extension of the segment  106  can cause the connected cavity formed by the hollow cavities  118  and  120  to increase in volume. As a result, the opposing force F 2  becomes smaller, and the pushing force F 3  can be greater than the opposing force F 2  and urge the segment  104  to slide relative to the segment  102  in the extending direction. Because the surface area of the end surface  134  is greater than the surface area of the end surface  136  and the surface area of the end surface  138 , the volume increase occurring inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  can be greater than the volume increase of the connected cavity formed by the hollow cavities  118  and  120  during extension of the segments  104  and  106 . Accordingly, when fluid is fed into the telescopic actuator  100  with a same flow speed, a relatively longer time is needed to fill in the volume inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104 , which results in an extending speed of the segment  104  that is slightly slower than an extending speed of the segment  106 . After the segment  104  has extended a certain length, the opposing force F 2  and the pushing force F 3  can become approximately equal and the segment  104  temporarily stops again. While the segment  106  continuously moves in the extending direction, the segment  104  thus can be in a floating state and slowly extend in a stop-and-go manner. This can prevent excessive impact of the segment  104  against the segment  102  when the segment  104  reaches the endpoint of its extending course, thereby preventing the occurrence of undesirable vibration and noise. 
     For retracting the telescopic actuator  100 , fluid release can be conducted through the ports  110  and  112 , and the segment  106  can slide relative to the segments  102  and  104  in the retracting direction under an external load applied thereon. The retraction of the segment  106  can cause the connected cavity formed by the hollow cavities  118  and  120  to decrease in volume. As a result, the opposing force F 2  can become slightly greater than the pushing force F 3 , which causes the segment  104  to slide relative to the segment  102  in the retracting direction. Because the surface area of the end surface  134  is greater than the surface area of the end surface  136  and the surface area of the end surface  138 , the volume decrease occurring inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104  can be greater than the volume decrease of the connected cavity formed by the hollow cavities  118  and  120  during retraction of the segments  104  and  106 . Accordingly, a relatively longer time is needed for fluid release from the volume inside the hollow cavity  116  between the end  102 A of the segment  102  and the end  104 A of the segment  104 , which results in a retracting speed of the segment  104  that is slower than a retracting speed of the segment  106 . After the segment  104  has retracted a certain length, the opposing force F 2  and the pushing force F 3  can become approximately equal and the segment  104  temporarily stops again. While the segment  106  continuously moves in the retracting direction, the segment  104  thus can be in a floating state and slowly retract in a stop-and-go manner. This can prevent excessive impact of the segment  106  against the segment  104  when the segment  106  reaches the endpoint of its retracting course, thereby preventing the occurrence of undesirable vibration and noise. 
     In conjunction with  FIGS.  1 - 4   ,  FIG.  5    is a schematic view illustrating an embodiment of a motion simulating apparatus  200 . Referring to  FIGS.  1 - 5   , the motion simulating apparatus  200  can include a support base  202 , an occupant platform  204 , the telescopic actuator  100 , the pressure source  152  and the conduits  154  and  156 . The support base  202  can extend generally horizontally, and can provide support for the occupant platform  204  and the telescopic actuator  100 . According to an example of construction, the support base  202  can include a plate structure. 
     The occupant platform  204  is disposed above the support base  202 , and is adapted to carry one or more occupants. The telescopic actuator  100  is disposed between the support base  202  and the occupant platform  204 , the segment  102  of the telescopic actuator  100  being connected to the support base  202 , and the segment  106  of the telescopic actuator  100  being connected to the occupant platform  204 . Like previously described, the pressure source  152  can be respectively connected to the ports  110  and  112  of the telescopic actuator  100  via the conduits  154  and  156 . During operation, the telescopic actuator  100  can extend and retract to cause upward and downward motions of the occupant platform  204 . 
     It will be appreciated that although the illustrated example of  FIG.  5    shows one telescopic actuator  100 , the motion simulating apparatus  200  is not limited to the illustrated example. The motion simulating apparatus  200  may include other actuators (not shown) for driving various motions of the occupant platform  204  as desired. 
     Advantages of the structures described herein include the ability to provide a telescopic actuator having a plurality of telescopically connected segments, wherein one of the segments can be configured to be in a floating state and extend or retract in a stop-and-go manner during operation. This can prevent excessive impact between segments that could produce undesirable vibration and noise and cause structural damages. The telescopic actuator described herein is suitable for use in actuating systems, and may be particularly advantageous for applications such as motion simulating apparatuses. 
     Realizations of the structures have been described only in the context of particular embodiments. These embodiments are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Structures and functionality presented as discrete components in the exemplary configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of the claims that follow.