Rotational overtravel protection to prevent over-rotation of objects

Abstract

A rotational overtravel protection device is provided for preventing over-rotation of at least one of a cable or a component operable with the rotational overtravel protection device. The device includes a housing, a rotatable shaft connected to the housing that can rotate relative to the housing, and a trigger device supported within the housing and rotatable with the rotatable shaft. The device also includes first and second rotational limit switches disposed within the housing. The switches are operable to be actuated by the trigger device to prevent rotation of the rotatable shaft when the rotatable shaft and the housing rotate relatively at least 180 degrees from a zero position in a first or second rotational direction, respectively.

Description

[Background technology]

[0001] In many applications, electrical or communication signals pass through components having moving parts. For example, the transfer of power and / or data in some applications needs to travel from a fixed part to a rotating part within an assembly. Thus, solutions exist that provide connectors for transmitting power and / or data from a fixed part to a moving part, such as a rotating part, within an assembly. Such connectors can be referred to as slip rings, rotary electrical interfaces, electrical rotary joints, etc. These connectors allow both relative rotation of the parts and the transmission of power and / or data.

[0002] However, the use of such connectors results in line losses for the power or data transmitted through them. In some applications, such line losses are unacceptable for the functioning of the system. In such situations, instead of using connectors, a cable can be used between the moving parts, which will twist with the relative rotation between the parts of the assembly. Naturally, the cable has a limit as to how much it can twist or rotate without being damaged. Thus, when using a cable between moving parts, it is important that the cable does not twist beyond its mechanical limits. In addition, the rotation of parts that rotate relative to each other must be limited to prevent any components that can operate with the relatively rotating parts from rotating into a fixed object or other component in the assembly. Thus, there is a need to provide a way to prevent rotational overtravel of the cable, while still allowing the moving parts to rotate sufficiently according to the needs of a given application.

[0003] Features and advantages of the disclosed technology will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the disclosed technology. [Brief description of the drawings]

[0004] [Figure 1]FIG. 2 is a front view of a rotational over-travel protection device according to an example of the present disclosure, the rotational over-travel protection device including an exemplary housing connected to a rotatable shaft that provides rotational over-travel protection. [Diagram 2] FIG. 2 is an isometric exploded view of components of the rotational overtravel protection device of FIG. [Figure 3A] FIG. 2 is a bottom view of the rotational overtravel protection device of FIG. 1 with the bottom cover removed to show the rotational overtravel protection device in a neutral position. [Figure 3B] 2 is a bottom view of the rotational overtravel protection device of FIG. 1 with the bottom cover removed to show the rotational overtravel protection device in a first operating position; FIG. [Figure 3C] 2 is a bottom view of the rotational overtravel protection device of FIG. 1 with the bottom cover removed to show the rotational overtravel protection device in a second operating position; FIG. [Figure 4] 1 is a schematic diagram of a rotational overtravel protection device according to an example of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] Reference will now be made to the exemplary embodiments illustrated and specific language will be used herein to describe the same, with it being understood, however, that no limitation of the scope of the exemplary embodiments is intended.

[0006] An initial overview of the inventive concepts is provided below, and specific examples are described in more detail below. This initial overview is intended to aid the reader in understanding the examples more quickly, but is not intended to identify key features or essential features of the embodiments, nor is it intended to limit the scope of the claimed subject matter.

[0007] In one example, the disclosure describes a rotational overtravel protection device for preventing over-rotation of an object, such as a cable, supported by the rotational overtravel protection device, and for preventing any component operable with the shaft (e.g., supported and driven by the shaft) from over-rotating and rotating into another component in an assembly incorporating the rotational overtravel protection device or into any fixed object in the vicinity of the assembly. The rotational overtravel protection device can include a housing and a rotatable shaft connected to the housing. The rotatable shaft and the housing can be operable to rotate relative to one another. The rotational overtravel protection device can further include a trigger device supported within the housing. The trigger device can be rotatable with the rotatable shaft through at least some degree of rotation of the rotatable shaft.

[0008] The rotational overtravel protection device may further include a first rotational limit switch disposed within the housing. The first rotational limit switch may be operable to be actuated by the trigger device to block rotation of the rotatable shaft when the rotatable shaft and the housing rotate relative to each other in a first rotational direction greater than 180 degrees from the zero position. The rotational overtravel protection device may also include a second rotational limit switch disposed within the housing. The second rotational limit switch may be operable to be actuated by the trigger device to block rotation of the rotatable shaft when the rotatable shaft and the housing rotate relative to each other in a second rotational direction greater than 180 degrees from the zero position, the second rotational direction being opposite to the first rotational direction.

[0009] In one example, the first and second rotational limit switches and the trigger device are supported in a common plane. The trigger device can include a pawl operable to mate with a protrusion disposed on the rotatable shaft. The protrusion can mate with the pawl after the shaft has rotated substantially 180 degrees from a zero position in both the first and second rotational directions.

[0010] In some examples, the rotational overtravel protection device may include a biasing member that biases (e.g., returns) the pawl to a neutral position when the pawl is not engaged with the protrusion. The biasing member may be a rotational spring coupled to the trigger device.

[0011] In some examples, the trigger device can include a cam surface and the first and second rotational limit switches can each include a cam follower. The trigger device can activate the first and second rotational limit switches when the cam surface engages the cam follower.

[0012] In some examples, the shaft can be associated with a first gear and the trigger device can include a second gear in communication with the first gear. The trigger device can include first and second stops in communication with the first and second rotational limit switches. The first and second rotational limit switches can include face plungers.

[0013] In another example, a rotational overtravel protection device is provided for preventing over-rotation of an object, such as a cable, and / or any component operable with (e.g., supported and driven by) the rotational overtravel protection device. The rotational overtravel protection device can include a housing and a rotatable shaft connected to the housing. The rotatable shaft and the housing can be operable to rotate relative to one another. The rotational overtravel protection device can also include a trigger device coupled to the rotatable shaft and configured to rotate in a plane of rotation.

[0014] The rotational overtravel protection device can include a first rotational limit switch disposed within the housing. The first rotational limit switch can be disposed flush with the surface of rotation of the trigger device. The rotational overtravel protection device can also include a second rotational limit switch disposed within the housing. The second rotational limit switch can also be disposed flush with the surface of rotation of the trigger device.

[0015] The trigger device can activate a first rotational limit switch to block rotation of the rotatable shaft when the rotatable shaft rotates more than 180 degrees from the zero position in a first rotational direction relative to the housing. The trigger device can also activate a second rotational limit switch to block rotation of the rotatable shaft when the rotatable shaft rotates more than 180 degrees from the zero position in a second rotational direction relative to the housing, the second rotational direction being opposite to the first rotational direction.

[0016] In some examples, the trigger device can include a pawl operable to mate with a protrusion disposed on the rotatable shaft. The protrusion can mate with the pawl after the shaft rotates 180 degrees from a zero position in both the first and second rotational directions. When the protrusion on the shaft mates with the pawl of the trigger device, the trigger device rotates with the shaft.

[0017] In some examples, the rotational overtravel protection device can include a biasing member that biases the pawl toward a neutral position when the pawl is not engaged with the protrusion. The biasing member can be a rotational spring coupled to the trigger device and the housing.

[0018] In some examples, the trigger device can include a cam surface and the first and second rotational limit switches can each include a cam follower. The trigger device can actuate the first and second rotational limit switches with the cam surface mated with the cam follower.

[0019] In some examples, the shaft can be associated with (e.g., integral with) a first gear and the trigger device can include a second gear that interfaces with the first gear. The trigger device can include first and second stops that interface with first and second rotational limit switches, which in some examples can include a face plunger.

[0020] In another example, a method is provided for providing rotational overtravel protection to prevent over-rotation of an object, such as a cable, and / or any component operable with (e.g., supported and driven by) the rotational overtravel protection device. The method can include rotating a shaft in a first direction relative to a housing at least 180 degrees from a zero position, rotating a trigger device to actuate a first rotational limit switch to prevent further rotation of the shaft in the first direction relative to the housing at a predetermined rotational position, rotating the shaft in a second direction relative to the housing at least 180 degrees from the zero position, and rotating the trigger device to actuate a second rotational limit switch to prevent further rotation of the shaft in the second direction relative to the housing at the predetermined rotational position, where the trigger device, the first rotational limit switch, and the second rotational limit switch are supported in a common plane.

[0021] In some examples, the first and second rotational limit switches are actuated by cam followers on the first and second rotational limit switches that interface with cam surfaces on the trigger device.

[0022] In some examples, the shaft is associated with a first gear and the trigger device is associated with a second gear that couples with the first gear.

[0023] To further illustrate the present technology, examples will now be provided with reference to the figures. Referring to FIG. 1, a rotational overtravel protection device 100 is provided. The rotational overtravel protection device 100 is operable to prevent over-rotation of an object, such as an object supported by, around, in, or otherwise operable with the device 100. In one example, the object can include a cable 10, such as a fiber optic cable, supported by the rotational overtravel protection device 10. In one example, the cable 10 can be supported via a connector or connector assembly supported within the rotational overtravel protection device 100. The connector or connector assembly can be supported by a housing 104. The cable 10 is routed through a shaft 102 and connected to the connector or connector assembly via a mating connector on the cable 10. In another example, the object can include one or more components (e.g., a shaft, as described below) operable with the rotational overtravel protection device 100 (e.g., supported and driven by the rotational overtravel protection device). The rotational overtravel protection device 100 can operate to prevent such components from rotating into any fixed object, or into any other object that may be in the vicinity of the rotational overtravel protection device 100, or into any other component in an assembly incorporating the rotational overtravel protection device 100. The rotational overtravel protection device 100 includes two components that rotate relative to one another and support a cable 10 and / or rotating parts. The cable 10 extends from one component to the other, causing the cable 10 to twist as the two components rotate. As shown in FIG. 1, the rotational overtravel protection device 100 includes components that rotate relative to one another in the form of a shaft 102 that is rotatable relative to a housing 104. Although not shown, one or more components can be coupled to or otherwise supported by the shaft 102 such that the rotation of the shaft 102 activates the components to be driven (i.e., rotated) by the shaft 102.

[0024] The shaft 102 and housing 104 shown in FIG. 1 are exemplary of two components that rotate relative to one another as part of the rotational overtravel protection device 100. However, one of ordinary skill in the art will recognize other rotatable components that may be used as part of the rotational overtravel protection device 100. Thus, the shaft 102 and housing 104 are not intended to be limiting in any way. For example, the rotational overtravel protection device 100 may be used to limit the rotation of a rotating base, a turntable, a rotatable display, or any other item. Regardless of configuration, the shaft 102 is rotatable relative to the housing 104, which causes a twist in the cable 10 and rotation of any component driven by the shaft 102.

[0025] 2, the shaft 102 is coupled to the housing 104 and is rotatable relative to the housing 104. Within the housing 104 are an upper spring mount 106, a rotation spring 108, and a lower spring mount 112. The upper spring mount 106, the rotation spring 108, and the lower spring mount 112 collectively define a trigger device 115 operable to activate over-rotation protection, as described in more detail below. The upper spring mount 106 and the lower spring mount 112 together house the rotation spring 108. The rotation spring 108 includes one or more protruding ends 110 configured to couple with the housing 104 to fix the position of the rotation spring 108. The coupling of the rotation spring 108 with the housing 104 is performed to bias the trigger device 115 to a neutral position. The rotation spring 108 is only one example of a biasing member that may be used to bias the trigger device 115 to a neutral position. As will be appreciated by those skilled in the art, other biasing members or mechanisms, such as other types of springs, may also be used.

[0026] The lower spring mount 112 includes an annular sidewall 114. The annular sidewall 114 includes a raised cam surface 116 on an outer surface of the annular sidewall 114. The raised cam surface 116 is operable to facilitate actuation of the rotational overtravel protection device 100 to provide overrotation protection, as will be described in more detail below. The annular sidewall 114 further includes a pawl 118 on an inner surface of the annular sidewall 114. The pawl 118 is sized and configured to couple with the shaft 102 to cause rotation of the trigger device 115 when the protrusion 118 engages the shaft 102.

[0027] Rotational overtravel protection device 100 further includes a washer 120, a snap ring 122, and a cable management member 124 supported within and by housing 104. Housing 104 is closed via an O-ring 126 and a cover 128. Cover 128 may be connected to housing 104 and may compress O-ring 126 via fasteners 130.

[0028] 3A-3C, the operation of the rotational overtravel protection device of FIGS. 1-2 to provide over-rotation protection and a method for providing rotational overtravel protection to prevent over-rotation of a cable and / or any driven components associated with the rotational overtravel protection device will be described. The shaft 102 includes a protrusion 132 disposed on an outer surface of the shaft 102. In FIG. 3A, the protrusion 132 and the shaft 102 are shown in a zero or reference position relative to the housing 104. In the zero or reference position, the cable (such as the cable 10 shown in FIG. 1) extending from the housing 104 to the shaft 102 is in a neutral or untwisted state. Similarly, in FIG. 3A, the trigger device 115 is biased to a neutral position by a biasing member (such as the rotational spring 108 shown in FIG. 2). In this example, the neutral position of the pawl 118 of the trigger device 115 is located approximately 180 degrees from the protrusion 132 of the shaft 102 in the zero position. Or, in other words, the neutral position of the pawl 118 of the trigger device 115 is located opposite the projection 132 of the shaft 102 when the shaft 102 is in the zero position.

[0029] Because the pawl 118 of the trigger device 115 is located 180 degrees from the zero position of the projection 132, the shaft 102 can rotate substantially or approximately 180 degrees in each direction relative to the housing 104 before the projection 132 of the shaft 102 mates with the pawl 118 of the trigger device 115. In other words, the shaft 102 rotates through at least a certain range of rotation or angle without mating with the trigger device 115. When the shaft 102 rotates sufficiently further, the projection 132 of the shaft can mate with the pawl 118 and the trigger device 115 is caused to rotate simultaneously with the shaft 102 through an additional range of rotation. In other words, the trigger device 115 rotates with the shaft 102 through at least a portion of the range or degree of rotation of the shaft 102 relative to the housing 104. Rotation of the trigger device 115 together with the shaft 102 from its neutral position through one or more predetermined degrees of rotation functions to facilitate blocking further rotation of the shaft 102, thus preventing over-rotation of the shaft 102 relative to the housing 104. As shown herein, over-rotation protection may be intended to protect the cable 10 from over-rotation to prevent damage or degradation of the cable 10. In another aspect, it may be intended to limit the rotation of one or more components coupled to or otherwise supported and driven by the shaft 102, such that the one or more components are prevented from rotating into one or more other fixed components in or near an assembly incorporating the rotational over-travel protection device. Although the present specification primarily describes preventing over-rotation of a cable, this is merely to illustrate one typical application in which over-rotation between two structures should be limited.

[0030] As the shaft 102 rotates relative to the housing 104, the projection 118 also rotates from the zero position. In this example, the shaft 102 can rotate in either direction from the zero position. The shaft 102 can be rotated, for example, by a motor. The motor, which controls the speed and position of rotation of the shaft 102, can be operated by a controller based on control instructions, such as user input, software, etc.

[0031] The rotational overtravel protection device further includes a first pair of rotational limit switches 134a, 134b and a second pair of rotational limit switches 136a, 136b. Each of the first pair of rotational limit switches 134a, 134b includes a cam follower (or cam follower surface) (see cam followers 135a, 135b, respectively) that can be sized and configured to actuate the first pair of rotational limit switches 134a, 134b. Similarly, each of the second pair of rotational limit switches 136a, 136b includes a cam follower (see cam followers 137a, 137b, respectively) that can be sized and configured to actuate the second pair of rotational limit switches 136a, 136b.

[0032] The first and second pairs of rotational limit switches 134a, 134b, 136a, 136b are operable to limit rotation of the shaft 102 relative to the housing 104 to prevent over-travel of the shaft 102 relative to the housing 104. This prevents over-rotation of the cables extending from the shaft 102 to the housing 104 (or over-rotation of one or more components supported and driven by the shaft 102). Activation of the switches 134a, 134b, 136a, 136b can limit rotation by sending a disabling control signal or command to the motor to stop or reverse rotation, by cutting power to the motor, by applying a brake, or through other control, electronic, or mechanical techniques.

[0033] In this example, the first and second pairs of rotational limit switches 134a, 134b, 136a, 136b provide primary and redundant mechanisms to ensure that overtravel of the shaft 102 relative to the housing 104 is prevented. For example, the first pair of rotational limit switches 134a, 134b can include an initial limit switch 134a (or a first limit switch in the first pair of limit switches) and a final limit switch 134b (or a second switch in the first pair of limit switches). The initial limit switch 134a can be operable to send an override control command to the motor, for example, to stop rotation of the shaft 102 relative to the housing 104. If the initial limit switch 134a fails to stop relative rotation of the shaft 102 and the housing 104, for example, the final limit switch 134b can be operable to cut power to the motor to ensure that the shaft 102 does not further rotate relative to the housing 104.

[0034] Similarly, the second rotational limit switches 136a, 136b may include an initial limit switch 136a (the first limit switch in the second pair of limit switches) and a final limit switch 136b (the second limit switch in the second pair of limit switches). The initial limit switch 136a may be operable to send a control command to the motor, for example, to stop rotation of the shaft 102 relative to the housing 104. If the initial limit switch 136a fails to stop the relative rotation of the shaft 102 and the housing 104, for example, the final limit switch 136b may be operable to cut power to the motor to ensure that the shaft 102 does not further rotate relative to the housing 104. The redundant final or second rotational limit switches in each of the first and second pairs of rotational limit switches may be referred to as redundant rotational limit switches.

[0035] While the above example shows two pairs of rotational limit switches 134a, 134b, 136a, 136b, other examples may eliminate the redundancy and include only one of the first pair of rotational limit switches 134a, 134b and one of the second pair of rotational limit switches 136a, 136b depending on the requirements for a given application. In other examples, the pairs of rotational limit switches 134a, 134b, 136a, 136b may be used for different purposes. For example, the first limit switch 134a, 136a may be used to limit the rotational speed of the shaft 102 relative to the housing 104, and the final limit switch 134b, 136b may prevent any further rotation of the shaft 102 relative to the housing 104.

[0036] Advantageously, the trigger device 115, the projection 118 on the shaft 102, and the first and second rotational limit switches 134a, 134b, 136a, 136b may all be supported in the same plane. In this example, the plane may be defined by the plane of rotation about which the trigger device 115 rotates. This allows the packaging and / or size of the rotational overtravel protection device to remain small. At the same time, the rotational overtravel protection device 100 allows the rotation of the shaft 102 relative to the housing to be greater than 180 degrees in each direction from the zero position. In this way, the rotational overtravel protection device may be compact while still allowing for a wide range of rotational movement.

[0037] As shown in FIG. 3B, the shaft 102 can rotate relative to the housing 104. In this example, the shaft 102 is shown rotated 270 degrees clockwise from the zero position (as shown in FIG. 3A). As illustrated by this exemplary degree of rotation of the shaft 102, the projection 132 of the shaft 102 engages with the pawl 118 of the trigger device 115, causing the trigger device 115 to rotate with the shaft 102 from its neutral position as shown in FIG. 3A. That is, the projection 132 of the shaft 102 rotates independently until it has rotated 180 degrees, at which point it engages with the pawl 118 of the trigger device 115. The shaft 102 and the trigger device 115 then rotate together as the shaft 102 rotates beyond 180 degrees from the zero position.

[0038] In this example, when the projection 132 of the shaft 102 reaches 270 degrees, the cam surface 116 of the trigger device 115 engages the cam follower 137a of the first rotation limit switch 136a. This activates the first rotation limit switch 136a and prevents further rotation of the shaft 102 relative to the housing 104. This may be done, for example, by sending an overriding control command to the motor to stop further clockwise rotation of the shaft 102 relative to the housing 104.

[0039] Although not explicitly shown, shaft 102 can also be rotated counterclockwise from the zero position, rotating trigger device 115 until protrusion 132 on shaft 102 engages pawl 118 and cam surface 116 engages cam follower 135a of first rotation limit switch 134a (also positioned at 270 degrees in this example), preventing further rotation in the counterclockwise direction.

[0040] When the shaft 102 returns to an angle less than 180 degrees from the zero position, the trigger device 115 disengages from the projection 132 of the shaft 102 and is biased back to its neutral position. The shaft 102 can be further rotated to the position in Figure 3A to place the projection 132 of the shaft 102 in the zero position with the pawl 118 again pointing 180 degrees from the projection 132 of the shaft 102. The trigger device 115 is biased to this position via a biasing member of the trigger device 115 (e.g., via the rotational spring 108 shown in Figure 2).

[0041] In this example using redundant rotation limit switches, if actuation of either of the initial limit switches 134a, 136a fails, actuation of the final limit switches 134b, 136b can be triggered by further rotation of the shaft 102 in the respective directions relative to the housing 104 to engage them. As shown in FIG. 3C, assuming failure of the first or initial rotation limit switch 136a, the prong 132 has rotated more than 270 degrees clockwise from the zero position to a position of approximately 300 degrees. As the trigger device 115 moves simultaneously with the rotating shaft 102 due to the coupling between the prong 132 and the pawl 118, further rotation in the same direction will cause the cam surface 116 of the trigger device 115 to engage the cam follower 137b of the final rotation limit switch 136b to actuate the final rotation limit switch 136b. In one example, activation of the final rotation limit switch 136b may cut off power to the motor and / or apply a brake to the shaft 102 to prevent the rotating shaft 102 from rotating further in the clockwise direction.

[0042] Similarly, although not explicitly stated, if the protrusion 132 rotates counterclockwise more than 270 degrees from the zero position, assuming failure of the rotation limit switch 134a, the final rotation limit switch 134b (located at 300 degrees in this example) can be activated via the cam surface 116 of the trigger device 115.

[0043] Thus, in the foregoing example, rotational overtravel protection device 100 may prevent over-rotation of the cable extending from shaft 102 to housing 104 (and / or over-rotation of one or more components supported and driven by shaft 102). Rotational overtravel protection device 100 may further be compact while still allowing rotation of greater than 180 degrees in each direction from the zero position.

[0044] Other variations are contemplated. For example, in applications with less critical space constraints, the initial rotation limit switch 134a, 134b can be offset in a different plane than the final rotation limit switch 136a, 136b, and the trigger device 115 can rotate on an inclined plane or screw. This could potentially allow the shaft 102 to rotate greater than 360 degrees relative to the housing 104, if mechanical constraints on the cable (and / or supported components) permit.

[0045] Additionally, although the trigger device 115 and rotational limit switches 134a, 136a are shown to limit the rotation of the shaft 102 relative to the housing 104 to 270 degrees from the zero position, other rotational limits (i.e., other limited degrees of rotation) greater or less than these can be set based on the needs of a given application, such as the mechanical limitations of a particular cable, or due to spatial constraints of one or more components supported and driven by the shaft 102 relative to one or more other components, such as fixed components in the assembly.

[0046] Another example of a rotational overtravel protection device is shown with respect to FIG. 4. In FIG. 4, the rotational overtravel protection device 400 includes a shaft 402 rotatable relative to a housing 404 in a manner similar to that described above. In this example, the shaft 402 is associated with (e.g., integral with) a first gear 440. The first gear 440 can be sized and configured to couple with a trigger device 460 that includes a second gear 461. The trigger device 460 includes a first stop 462 and a second stop 464 operable to actuate a first rotational limit switch 466 and a second rotational limit switch 468, respectively. In this example, the first and second stops 462, 464 couple with respective plungers 467, 469 disposed on the first and second rotational limit switches 466, 468. Plungers 467, 469 actuate first and second rotational limit switches 466, 468, respectively, which may provide functionality similar to the rotational limit switches described above to prevent further rotation of shaft 402 relative to housing 404.

[0047] The relative size of the first gear 440 to the second gear 461, and the placement of the stops 462, 464 and / or the first and second rotational limit switches 466, 468 may be determined based on a desired limit of rotation of the shaft 402 from the zero position. The gear reduction between the first gear 440 and the second gear 461 may allow rotation of the shaft 402 greater than 180 degrees in each direction from the zero position. Additionally, in the example shown in FIG. 4, the first gear 440, the trigger device 460, and the first and second rotational limit switches 466, 468 are advantageously positioned or otherwise supported in a common plane, allowing the rotational overtravel protection device 400 to remain compact.

[0048] Reference has been made to the examples illustrated in the drawings, and specific language has been used herein to describe these. It will be understood, however, that no limitation of the scope of the technology is intended thereby. Modifications and further variations of the features illustrated herein, as well as further applications of the examples illustrated herein, should be considered within the scope of the description.

[0049] Although the present disclosure may not expressly disclose that some embodiments or features described herein may be combined with other embodiments or features described herein, the present disclosure should be read to describe any such combinations that may be performed by one of ordinary skill in the art. The use of "or" in this disclosure should be understood to mean a non-exclusive or, i.e., "and / or," unless otherwise indicated herein.

[0050] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more examples. In the foregoing description, numerous specific details, such as examples of various configurations, are provided to provide a thorough understanding of examples of the described technology. However, it will be understood that the technology can be practiced without one or more of the specific details, or with other methods, components, devices, etc. In other instances, well-known structures or operations have not been shown or described in detail to avoid obscuring aspects of the technology.

[0051] Although the subject matter has been described in language specific to structural features and / or operations, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features and operations described above. Rather, the specific features and operations described above are disclosed as example forms of implementing the claims. Numerous modifications and alternative arrangements may be devised without departing from the spirit and scope of the described technology.

Claims

1. A rotational over-travel protection device, the rotational over-travel protection device comprising: Housing and a rotatable shaft connected to the housing, the rotatable shaft and the housing being operable to rotate relative to one another; and a trigger device supported within the housing, the trigger device rotatable with the rotatable shaft through at least some degree of rotation of the rotatable shaft, the trigger device including an annular sidewall having an outer surface and an inner surface, the inner surface including a pawl operable to mate with a protrusion disposed on the rotatable shaft; a first rotational limit switch disposed within the housing, the first rotational limit switch operable to be actuated by the outer surface of the trigger device to prevent rotation of the rotatable shaft when the rotatable shaft and the housing rotate relative to each other in a first rotational direction greater than 180 degrees from a zero position; and a second rotational limit switch disposed within the housing, the second rotational limit switch operable to be actuated by the outer surface of the trigger device to block rotation of the rotatable shaft when the rotatable shaft and the housing rotate relative to each other in a second rotational direction greater than 180 degrees from the zero position, the second rotational direction being opposite to the first rotational direction; Including, Rotational overtravel protection device.

2. 2. The rotational overtravel protection device of claim 1, wherein said first and second rotational limit switches and said trigger device are disposed at the same height within said housing.

3. 2. The rotational overtravel protection device of claim 1, wherein the protrusion engages the pawl after the rotatable shaft rotates substantially 180 degrees from the zero position in both the first rotational direction and the second rotational direction.

4. 4. The rotational overtravel protection device of claim 3, further comprising a biasing member biasing said pawl to a neutral position when said pawl is disengaged from said projection.

5. The rotational overtravel protection device of claim 4 , wherein said biasing member includes a rotational spring coupled with said trigger device and said housing.

6. the outer surface of the trigger device includes a raised cam surface, and the first and second rotational limit switches each include a cam follower; 2. The rotational overtravel protection device of claim 1, wherein the trigger device is configured to actuate the first and second rotational limit switches when the raised cam surface engages the cam follower.

7. A rotational over-travel protection device, the rotational over-travel protection device comprising: Housing and a rotatable shaft connected to the housing, the rotatable shaft and the housing being operable to rotate relative to one another; and a trigger device including an annular sidewall having an outer surface and an inner surface, the inner surface including a pawl operable to mate with a protrusion disposed on the rotatable shaft, the trigger device configured to rotate in a plane of rotation; a first rotation limit switch disposed within the housing and positioned at the same height as the trigger device; a second rotation limit switch disposed within the housing and positioned at the same height as the rotation surface of the trigger device; the outer surface of the trigger device actuates the first rotational limit switch to prevent rotation of the rotatable shaft when the rotatable shaft rotates greater than 180 degrees in a first rotational direction from a zero position relative to the housing; the outer surface of the trigger device actuates the second rotational limit switch to prevent rotation of the rotatable shaft when the rotatable shaft rotates greater than 180 degrees from the zero position in a second rotational direction relative to the housing, the second rotational direction being opposite to the first rotational direction. Rotational overtravel protection device.

8. 8. The rotational overtravel protection device of claim 7, wherein when the projection of the rotatable shaft engages the pawl of the trigger device, the trigger device rotates with the rotatable shaft.

9. 9. The rotational overtravel protection device of claim 8, wherein the protrusion engages the pawl after the rotatable shaft rotates substantially 180 degrees from the zero position in both the first rotational direction and the second rotational direction.

10. 10. The rotational overtravel protection device of claim 9, further comprising a biasing member biasing said pawl to a neutral position when said pawl is not engaged with said projection.

11. The rotational overtravel protection device of claim 10 , wherein the biasing member includes a rotational spring coupled to the trigger device and the housing.

12. the outer surface of the trigger device includes a raised cam surface, and the first and second rotational limit switches each include a cam follower; 8. The rotational overtravel protection device of claim 7, wherein said trigger device actuates said first and second rotational limit switches when said raised cam surface engages said cam follower.

13. 1. A method for providing rotational overtravel protection to an object, the method comprising: rotating the shaft in a first direction relative to the housing at least 180 degrees from a zero position to cause a protrusion disposed on the shaft to engage a pawl on an inner surface of an annular sidewall of the trigger device; rotating the trigger device to actuate a first rotational limit switch on an exterior surface of the trigger device to prevent further rotation of the shaft in the first direction relative to the housing at a predetermined rotational position; rotating the shaft in a second direction relative to the housing at least 180 degrees from the zero position to cause the projection disposed on the shaft to engage the pawl on the inner surface of the annular sidewall of the trigger mechanism; rotating the trigger device to actuate a second rotational limit switch on the outer surface of the trigger device to prevent further rotation of the shaft in the second direction relative to the housing at a predetermined rotational position, the trigger device, the first rotational limit switch, and the second rotational limit switch being positioned and supported at the same height within the housing. method.

14. 14. The method of claim 13, wherein the first and second rotational limit switches are actuated by cam followers on the first and second rotational limit switches that interface with raised cam surfaces on the exterior surface of the trigger device.

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