Patent Description:
This application relates to robotic systems, and in particular, to multi-stage stop devices, systems, and methods for mechanically limiting and/or stopping rotation of robotic arms or other components.

Robotic arms may be used to perform various tasks, and are particularly common in automation. Robotic arms typically comprise a plurality of links connected by one or more joints. The one or more joints are driven by various types of actuators (e.g., electric motors, hydraulics, etc.) to control articulation of the robotic arm to position an end effector that is configured to perform a task. In some instances, robotic arms can include physical stop devices (e.g., hard stops) that can be configured to limit rotational motion between links of the arm. Such stop devices can limit damage to the robotic arm or injury to others in the event of a failure of the robotic arm.

German patent <CIT> discloses a method for optimizing the operation of a handling unit, in particular a linear or pivot unit, wherein the unit comprises a base part, a movement part arranged on the base part to be moveable between two end positions, a drive unit for moving the movement part, and an adjustable braking unit for braking the movement part.

US patent <CIT> discloses a stopper for use with an industrial robot including a mount base, a turning base capable of turning over the mount base about a pivot extending in the vertical direction, a fixed engagement section fixed to the mount base, a turning engagement section fixed to the turning base, and the fixed engagement section engaging the turning engagement section as a result of turning of the turning base.

Japanese patent <CIT> discloses a means to absorb a large reaction force by abutting a stopper and movable side stopper main body to a stationary side stopper main body directly.

This application describes multi-stage stop devices with the features of claim <NUM>. Optional features are disclosed in the dependent claims.

The multi-stage stop devices described herein are referred to as "multi-stage" because, as will be described below, they include two stages for stopping rotational motion. During a first stage, the rotational motion compresses a compressible member to absorb and dissipate at least some of the force generated by the collision. A second stage provides a hard stop that stops any further rotation. The multi-stage stop devices described herein can include a collapsing pin configured to compress the compressible member during the first stage. After the pin has collapsed, a rigid sidewall of a multi-stage stop device provides a hard stop preventing further rotation during the second stage.

The features and advantages of the multi-stage stop devices, systems, and methods described herein will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. These drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope. In the drawings, similar reference numbers or symbols typically identify similar components, unless context dictates otherwise. The drawings may not be drawn to scale.

The features of the multi-stage stop devices, systems, and methods of the present disclosure will now be described in detail with reference to certain embodiments illustrated in the figures. The illustrated embodiments described herein are provided by way of illustration and are not meant to be limiting. Other embodiments can be utilized, and other changes can be made, without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects and features of the present disclosure described below and illustrated in the figures can be arranged, substituted, combined, and designed in a wide variety of different configurations by a person of ordinary skill in the art, all of which are made part of this disclosure.

<FIG> is an isometric view of an embodiment of a robotic arm <NUM> that can include a multi-stage stop device <NUM> as described herein. In the illustrated embodiment, the multi-stage stop device <NUM> is not visible in <FIG>. The multi-stage stop device <NUM> is shown, for example, in <FIG>, which are described further below. As shown in <FIG>, in the illustrated embodiment, the robotic arm <NUM> includes a base <NUM>, a first link <NUM>, a second link <NUM>, and an end effector <NUM>. The multi-stage stop device <NUM> described further below can also be used on other types of robotic arms or systems. The illustrated robotic arm <NUM> is provided by way of example only.

The base <NUM> can be configured to support the other portions of the robotic arm <NUM>. In some embodiments, the base <NUM> houses many of the electronic components for the robotic arm <NUM>. The first link <NUM> can be connected to the base <NUM> by a first rotational joint <NUM>. The first rotational joint <NUM> allows the first link <NUM> to rotate relative to the base <NUM>. In the illustrated embodiment, the first link <NUM> rotates relative to the base <NUM> about a first axis of rotation <NUM>. In general, rotation of the first link <NUM> relative to the base <NUM> may be controlled through the execution of one or more sequences of instructions (i.e., software) and/or by customized hardware (e.g., application-specific integrated circuit(s), field-programmable gate array(s), etc.). However, it may be beneficial or required to provide a mechanical mechanism for limiting or stopping rotation of the first link <NUM> relative to the base <NUM>, for example, in the event of a failure of the robotic arm <NUM>. The multi-stage stop device <NUM> described in this application can be included at the first rotational joint <NUM> to provide this functionality. For example, the multi-stage stop device <NUM> can be included at the first rotational joint <NUM> to limit or stop rotation of the first link <NUM> relative to the base <NUM>.

With continued reference to <FIG>, the second link <NUM> is connected to the first link <NUM> by a second rotational joint <NUM>. The second rotational joint <NUM> allows the second link <NUM> to rotate relative to the first link <NUM>. In the illustrated embodiment, the second link <NUM> rotates relative to the first link <NUM> about a second axis of rotation <NUM>. Again, in general, rotation of the second link <NUM> relative to the first link link <NUM> may be controlled or limited by software or customized hardware. It may, however, be beneficial or required to provide a mechanical mechanism for limiting or stopping rotation of the second link <NUM> relative to the first link <NUM> in the event of a failure of the robotic arm <NUM>. The multi-stage stop device <NUM> described below can, in some embodiments, be included at the second rotational joint <NUM> to provide this functionality. For example, the multi-stage stop device <NUM> can be included at the second rotational joint <NUM> to limit or stop rotation of the second link <NUM> relative to the first link <NUM>. In some embodiments, a different type of stop device can be included at the second rotational joint <NUM>.

In the illustrated embodiment, the base <NUM>, first link <NUM>, and second link <NUM> are arranged to form a selective compliance assembly robot arm (SCARA). The multi-stage stop device <NUM> may be used at any of the rotational joints of a SCARA. The multi-stage stop device <NUM> may also be configured for use with other types of robotic arms (e.g., non-SCARA robotic arms).

In the illustrated embodiment of <FIG>, the robotic arm <NUM> includes an end effector <NUM>. In this embodiment, the end effector <NUM> is positionable by rotating the first and/or second links <NUM>, <NUM> about the first and/or second rotational axes <NUM>, <NUM>. The end effector <NUM> can be configured to perform various tasks as will be apparent to those of ordinary skill in the art.

In many of the examples described below, the multi-stage stop device <NUM> is described with reference to the first rotational joint <NUM> between the first link <NUM> and the base <NUM>. This is done for ease of description with the understanding that the multi-stage stop device <NUM> can alternatively or additionally be used at any other rotational joint of the robotic arm <NUM>.

<FIG> illustrate an embodiment of the multi-stage stop device <NUM> according to the present disclosure. <FIG> is a top perspective view, <FIG> is a bottom perspective view, and <FIG> is a top view of the multi-stage stop device <NUM>.

As mentioned above, the multi-stage stop device <NUM> can be configured to stop or limit rotation at a rotational joint of a robotic arm or system, such as the robotic arm <NUM> illustrated in <FIG> or others. For example, with reference to the robotic arm <NUM> of <FIG>, the multi-stage stop device <NUM> can be installed at the first rotational joint <NUM> to stop or limit rotation of the first link <NUM> relative to the base <NUM> and/or the multi-stage stop device <NUM> can be installed at the second rotational joint <NUM> to stop or limit rotation of the second link <NUM> relative to the first link <NUM>. Example installation of the multi-stage stop device <NUM> will be described in greater detail below with reference to <FIG>.

In the illustrated embodiment of <FIG>, the multi-stage stop device <NUM> includes a frame member <NUM>, a first pin <NUM>, a second pin <NUM>, and a compressible member <NUM>. These features will now be described in more detail.

The frame member <NUM> can comprise a body or housing for the multi-stage stop device <NUM>. In the illustrated embodiment, the frame member <NUM> comprises a single, unitary piece. In some embodiments, the frame member <NUM> may comprise more than one piece joined together to form the frame member <NUM>. The frame member <NUM> may be made from a strong, rigid material, such as many types of metals. In some embodiments, the frame member <NUM> is made from steel.

As shown in <FIG>, in the illustrated embodiment, the frame member <NUM> includes a first sidewall <NUM>. The first sidewall <NUM> can include a first opening <NUM> defined therein. That is, the first opening <NUM> can be formed through and extend through the first sidewall <NUM>. As illustrated, in some embodiments, the first opening <NUM> extends along a first pin axis <NUM>. The first opening <NUM> can be configured to receive the first pin <NUM> therethrough. For example, as illustrated, the first pin <NUM> extends through the first opening <NUM> and through the first sidewall <NUM> of the frame member <NUM>. The first opening <NUM> can be configured such that the first pin <NUM> is slidingly received within the first opening <NUM>. To this end, in some embodiments, the first opening <NUM> can be slightly larger (e.g., being about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% larger in terms of cross-sectional area, diameter, etc.) than the first pin <NUM> so as to allow the first pin <NUM> to slide back and forth through the first opening <NUM> along the first pin axis <NUM>. In the illustrated embodiment, the first opening <NUM> is shown with a circular cross-section that corresponds to the circular cross-section of the first pin <NUM>. In general, the cross-section of the first opening <NUM> is configured to correspond to the cross-section of the first pin <NUM>, although this need not always be the case. Further, the cross-sections of the first opening <NUM> and the first pin <NUM> can comprise other, non-circular shapes in some embodiments.

Similarly, in the illustrated embodiment, the frame member <NUM> also includes a second sidewall <NUM>. The second sidewall <NUM> can be positioned on the frame member <NUM> on a side of the frame member <NUM> that is opposite the first sidewall <NUM>. In the illustrated embodiment, the second sidewall <NUM> includes a second opening <NUM> defined therein. That is, the second opening <NUM> can be formed through and extend through the second sidewall <NUM>. As illustrated, in some embodiments, the second opening <NUM> extends along a second pin axis <NUM>. The second opening <NUM> can be configured to receive the second pin <NUM> therethrough. For example, as illustrated, the second pin <NUM> extends through the second opening <NUM> and through the second sidewall <NUM> of the frame member <NUM>. The second opening <NUM> can be configured such that the second pin <NUM> is slidingly received within the second opening <NUM>. For example, the second opening <NUM> can be slightly larger (e.g., <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% larger) than the second pin <NUM> so as to allow the second pin <NUM> to slide back and forth through the second opening <NUM> along the second pin axis <NUM>. In some embodiments, the second opening <NUM> is the same size as the first opening <NUM>, although this need not be the case in all embodiments. In the illustrated embodiment, the second opening <NUM> is shown with a circular cross-section that corresponds to the circular cross-section of the second pin <NUM>. In general, the cross-section of the second opening <NUM> is configured to correspond to the cross-section of the second pin <NUM>, although this need not always be the case. Further, the cross-sections of the second opening <NUM> and the second pin <NUM> can comprise other, non-circular shapes in some embodiments.

As shown in <FIG>, the frame member <NUM> may also include an outer sidewall <NUM>. In the illustrated embodiment, the outer sidewall <NUM> extends between the first sidewall <NUM> and the second sidewall <NUM> at the top of the frame member <NUM> (relative to the orientation shown in the figure). Additionally, the frame member <NUM> can also include an inner portion <NUM>. As shown, in some embodiments, the inner portion <NUM> extends between the first sidewall <NUM> and the second sidewall <NUM> at the bottom of the frame member <NUM> (relative to the orientation shown in the figure).

Thus, the frame member <NUM> can include the first sidewall <NUM>, the second sidewall <NUM>, the outer sidewall <NUM>, and the inner portion <NUM> as illustrated, for example, in <FIG>. The first sidewall <NUM>, the second sidewall <NUM>, the outer sidewall <NUM>, and the inner portion <NUM> can be arranged to define a space <NUM> therebetween. For example, as shown in <FIG>, the space <NUM> is bounded and defined on a first side by the first sidewall <NUM>, on a second side by the second sidewall <NUM>, on a third side by the outer sidewall <NUM>, and on a fourth side by the inner portion <NUM>. As will be described in more detail below, the compressible member <NUM> can be received and positioned within the space <NUM>. That is, the compressible member <NUM> can be positioned between the first sidewall <NUM>, the second sidewall <NUM>, the outer sidewall <NUM>, and the inner portion <NUM> as illustrated.

The first sidewall <NUM>, the second sidewall <NUM>, the outer sidewall <NUM>, and the inner portion <NUM> can be arranged such that the frame member <NUM> comprises a keyed-profile <NUM>. When used with reference to the frame member <NUM>, the term "profile" refers to the outer profile or outer shape of the frame member <NUM> when viewed from above (e.g., as shown in <FIG>) or below. For example, in the illustrated embodiment, the profile of the frame member <NUM> comprises a generally four-sided, wedge-like shape with rounded corners. Certain features of this shape will be described in more detail below with reference to <FIG>. Additionally, the illustrated profile is provided by way of example only and other profile shapes for the frame member <NUM> are possible. The profile of the frame member <NUM> is referred to as "keyed" because, as will be described below with reference to <FIG> and <FIG>, it can be configured to fit within a corresponding keyed-recess <NUM> when mounted to the robotic arm <NUM>.

With continued reference to <FIG>, features present in some embodiments of the first pin <NUM> and the second pin <NUM> will now be described. In the illustrated embodiment, the first pin <NUM> comprises a first shaft <NUM>. As illustrated, the first shaft <NUM> comprises a circular cross-section, although this need not be the case in all embodiments, and other cross-sectional shapes for the first shaft <NUM> are possible. The first shaft <NUM> extends along the first pin axis <NUM> between a first head <NUM> and a first distal end <NUM>. As shown in <FIG>, the first shaft <NUM> of the first pin <NUM> extends through the first opening <NUM> of the first sidewall <NUM>. As described above, the first shaft <NUM> can be slidably received within the first opening <NUM> such that the first pin <NUM> can slide back and forth through the first opening <NUM> along the first pin axis <NUM>. To facilitate sliding, in some embodiments, the first shaft <NUM> can be slightly smaller (e.g., about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% smaller) than the first opening <NUM>.

As shown in <FIG>, the first head <NUM> of the first pin <NUM> can be positioned between the first sidewall <NUM> and the compressible member <NUM>. In some embodiments, for example, as illustrated, the first head <NUM> can comprise a shape or diameter that is larger than the first opening <NUM>. This may be included to retain the first pin <NUM> within the first opening <NUM>. For example, as illustrated, the first head <NUM> prevents the first pin <NUM> from sliding completely out of the first opening <NUM>. Thus, from the position illustrated in <FIG>, the first pin <NUM> can slide inward toward the compressible member <NUM> (causing the compressible member <NUM> to be compressed) but is limited or prevented from sliding outward (away from the compressible member) because the first head <NUM> does not fit through the first opening <NUM>.

An enlarged first head <NUM>, as illustrated in <FIG>, may also beneficially distribute forces onto a larger surface area of the compressible member <NUM>. As will be described in more detail below with reference to <FIG>, during use of the multi-stage stop device <NUM>, a force may be imparted on the distal end <NUM> of the first pin <NUM>. The force may cause the first pin <NUM> to slide along the first pin axis <NUM> towards the compressible member <NUM> (causing compression of the compressible member <NUM>). The first head <NUM> may contact the compressible member <NUM> and transfer the force acting on the first pin <NUM> to the compressible member <NUM>. The enlarged first head <NUM> can distribute the force over a larger section of the compressible member <NUM>.

In many respects, the second pin <NUM> can be similar to the first pin <NUM>. For example, in the illustrated embodiment, the second pin <NUM> comprises a second shaft <NUM>. The second shaft <NUM> can comprise a circular cross-section, although this need not be the case in all embodiments, and other cross-sectional shapes for the second shaft <NUM> are possible. The second shaft <NUM> extends along the second pin axis <NUM> between a second head <NUM> and a second distal end <NUM>. As shown in <FIG>, the second shaft <NUM> of the second pin <NUM> extends through the second opening <NUM> of the second sidewall <NUM>. As described above, the second shaft <NUM> can be slidably received within the second opening <NUM> such that the second pin <NUM> can slide back and forth through the second opening <NUM> along the second pin axis <NUM>. To facilitate sliding, in some embodiments, the second shaft <NUM> can be slightly smaller (e.g., about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% smaller) than the second opening <NUM>.

As shown in <FIG>, the second head <NUM> of the second pin <NUM> can be positioned between the second sidewall <NUM> and the compressible member <NUM>. In some embodiments, for example, as illustrated, the second head <NUM> can comprise a shape or diameter that is larger than the second opening <NUM>. This may be included to retain the second pin <NUM> within the second opening <NUM>. As illustrated, the second head <NUM> prevents the second pin <NUM> from sliding completely out of the second opening <NUM>. Thus, from the position illustrated in <FIG>, the second pin <NUM> can slide inward toward the compressible member <NUM> (causing the compressible member <NUM> to be compressed) but is limited or prevented from sliding outward (away from the compressible member) because the second head <NUM> does not fit through the second opening <NUM>. Similar to the first pin <NUM>, an enlarged second head <NUM> on the second pin <NUM>, as illustrated in <FIG>, may also beneficially distribute forces onto a larger surface area of the compressible member <NUM>.

The first pin <NUM> and the second pin <NUM> can be made from a strong, rigid material, such as many types of metals. In some embodiments, the first pin <NUM> and the second pin <NUM> are made from steel. In some embodiments, the first pin <NUM> and the second pin <NUM> are cast. In some embodiments, the first pin <NUM> and the second pin <NUM> are identical.

As illustrated in <FIG>, in some embodiments, the compressible member <NUM> is positioned within the space <NUM> between the first head <NUM> of the first pin <NUM> and the second head <NUM> of the second pin <NUM>. More specifically, in some embodiments, the first head <NUM> of the first pin <NUM> acts on a first wall <NUM> of the compressible member <NUM> and the second head <NUM> of the second pin <NUM> acts on a second wall <NUM> of the compressible member <NUM>. Thus, in some embodiments, a force acting on either the first distal end <NUM> of the first pin <NUM> or the second distal end <NUM> of the second pin <NUM> may be transmitted to the compressible member <NUM> by the first pin <NUM> or the second pin <NUM>. If the force is sufficient, it may cause the compressible member <NUM> to compress, which can beneficially absorb the force. As mentioned above, this may provide the first stage of the multi-stage stop device <NUM>. For example, in the event of a collision, some of the force may be absorbed by compression of the compressible member <NUM>, as explained in further detail below with reference to <FIG>.

The illustrated embodiment, which includes the first pin <NUM> and the second pin <NUM> on opposite sides of the compressible member <NUM>, may beneficially be used to limit rotational motion in both rotational directions. Further, the design may be advantageous because it can be configured to use a single compressible member <NUM> which is acted upon by both the first pin <NUM> and the second pin <NUM>. Such a configuration may advantageously reduce the size of the multi-stage stop device <NUM> allowing it to be installed in small spaces. Although the illustrated embodiment includes the first pin <NUM> and the second pin <NUM>, in some embodiments, only a single pin may be included. A single pin device may be used to limit rotation in only a single direction.

In the illustrated embodiment, the compressible member <NUM> comprises a hexagonal shape. This need not be the case in all embodiments, and other shapes for the compressible member <NUM> are possible.

As shown in the illustrated embodiment of <FIG>, the compressible member <NUM> can comprise a block of material. The material can be selected to have a hardness that is configured to absorb forces to be expected during a collision. The forces expected during a collision can be determined based on consideration of various parameters of the robotic arm, including, for example, the size and weight of the robotic arm and various links thereof, the speed at which the robotic arm rotates, the potential payloads with which the robotic arm operates, and the placement of the multi-stage stop device <NUM>.

For example, larger, heavier robotic arms working with heavier payloads may produce larger forces during collision than smaller, lighter robotic arms working with lighter payloads. As another example, robotic arms operating at higher speeds may produce larger forces during collision than robotic arms working at slower speeds. As another example, a multi-stage stop device <NUM> placed closer to an axis of rotation may experience larger forces during a collision than a multi-stage stop device <NUM> placed further from an axis of rotation.

In some embodiments, when higher forces are expected, the compressible member <NUM> may comprise a harder material. In some embodiments, the material of the compressible member <NUM> may have a shore hardness of at least about 40A, 50A, 60A, 70A, 80A, 90A, 100A, 10D, 20D, 30D, 40D, 50D, 60D, 70D, 75D, 80D, 90D, or 100D. In some embodiments, the compressible member <NUM> may comprise a rubber material. In some embodiments, the compressible member <NUM> may comprise a spring.

In some embodiments, for example, as illustrated in <FIG>, the multi-stage stop device <NUM> can include a mounting aperture <NUM> configured to receive a fastener <NUM> for attaching the multi-stage stop device <NUM> to the robotic arm <NUM>. In the illustrated embodiment, the mounting aperture <NUM> is formed through the inner portion <NUM> of the frame member <NUM>. In the illustrated embodiment, the fastener <NUM> comprises a bolt as shown. Other mechanisms for securing the multi-stage stop device <NUM> to the robotic arm <NUM> are also possible. <FIG>, described below, shows one example of the multi-stage stop device <NUM> in an installed position.

<FIG> is a bottom perspective view of the multi-stage stop device <NUM>. As illustrated in <FIG>, in some embodiments, the frame member <NUM> further includes a bottom wall <NUM> (i.e., bottom wall, according to its configuration as installed in the robotic device of <FIG>). The bottom wall <NUM> can extend between the first sidewall <NUM>, the second sidewall <NUM>, the outer sidewall <NUM>, and the inner portion <NUM>. The bottom wall <NUM> can partially define the space <NUM> in which the compressible member <NUM> is positioned. In some embodiments, the bottom wall <NUM> includes an aperture <NUM> formed therein as shown.

<FIG> is a top view of the multi-stage stop device <NUM> and illustrates that, in some embodiments, some aspects of the profile <NUM> of the frame member <NUM> can be determined in part based on the placement of the multi-stage stop device <NUM> relative to an axis of rotation <NUM> of a rotational joint at which the multi-stage stop device <NUM> is installed. As shown in <FIG>, the first sidewall <NUM> and the second sidewall <NUM> may be formed at an angle α relative to each other. The angle α may give the frame member <NUM> a wedge-like shape as shown. The angle α can be configured such that the planes of the first sidewall <NUM> and the second sidewall <NUM> intersect at the axis of rotation <NUM>. Such an angle α may provide that the first and second pin axes <NUM>, <NUM> are tangent to circle <NUM> formed at a radius R from the axis of rotation. The first and second pins <NUM>, <NUM> may be positioned at the radius R from the circle <NUM>. An angle β formed between the first wall <NUM> and the second wall <NUM> of the compressible member <NUM> may be substantially or about equal to the angle α. This may provide that the forces imported by the first pin <NUM> or the second pin <NUM> on the compressible member <NUM> act in a direction that is normal to the first wall <NUM> or the second wall <NUM>. In some embodiments, this configuration may facilitate installation of the multi-stage stop device <NUM> on the interior of the robotic arm <NUM>.

<FIG> is a perspective view illustrating an embodiment of a keyed-recess <NUM> configured to receive the multi-stage stop device <NUM> of <FIG>. In the illustrated embodiment, the keyed-recess <NUM> is formed on the first link <NUM> of the robotic arm <NUM> of <FIG>. In particular, in the illustrated embodiment, the keyed-recess <NUM> is formed on an internal portion or surface <NUM> of a housing <NUM> of the first link <NUM>. The internal portion or surface <NUM> of the housing <NUM> may be a portion of the first link <NUM> that is not visible when the robotic arm <NUM> is assembled. In some embodiments, the internal portion or surface <NUM> of the housing <NUM> may face an internal surface or portion <NUM> of the base <NUM> when the robotic arm <NUM> is assembled (see, for example, <FIG>). In some embodiments, however, the keyed-recess <NUM> can be positioned on an external portion or surface of the housing <NUM>. Further, as will be described further below, the keyed-recess <NUM> may be formed in different locations as well. For example, in some embodiments, the keyed-recess <NUM> may be formed on an internal or external surface of the base <NUM>. In some embodiments, the multi-stage stop device <NUM> can be positioned in a joint between two links of a robotic arm. Accordingly, in some embodiments, the keyed-recess <NUM> can be positioned on either of the links.

As shown in <FIG>, the keyed-recess <NUM> is configured in shape and size to correspond to the keyed-profile <NUM> of the frame member <NUM> of the multi-stage stop device <NUM>. The keyed-recess <NUM> may be configured to closely receive the multi-stage stop device <NUM>, such that, when the multi-stage stop device <NUM> is positioned within the keyed-recess <NUM>, play (e.g., relative movement, clearance, lash, etc.) between the multi-stage stop device <NUM> and the keyed-recess <NUM> is limited.

The keyed-recess <NUM> can include a mounting aperture <NUM> as shown. The mounting aperture <NUM> can be configured to receive a portion of the fastener <NUM> of the multi-stage stop device <NUM> to secure the multi-stage stop device <NUM> into the keyed-recess <NUM>. For example, the fastener <NUM> can extend through the mounting aperture <NUM> of the frame member <NUM> of the multi-stage stop device <NUM> and into the mounting aperture <NUM> of the keyed-recess <NUM>. In some embodiments, the fastener <NUM> comprises a bolt and the mounting aperture <NUM> is threaded to receive a threaded end of the bolt.

In some embodiments, the keyed-recess <NUM> also include a protrusion <NUM> as illustrated. The protrusion <NUM> may be configured to extend partially into the space <NUM> of the multi-stage stop device <NUM> to hold the compressible member <NUM> in place. For example, in the illustrated embodiment, the protrusion <NUM> comprises a V-like shape configured to extend into the space <NUM> between the first sidewall <NUM> and the second sidewall <NUM> of the frame member <NUM> and to contact a surface of the compressible member <NUM>. Although the protrusion <NUM> is illustrated with a V-like shape, in other embodiments, the protrusion <NUM> may comprise other shapes.

As noted above, the keyed-recess <NUM> is configured to at least partially receive the multi-stage stop device <NUM> therein. This may serve one or more beneficial purposes. For example, the keyed-recess <NUM> may serve to ensure that the multi-stage stop device <NUM> is correctly oriented and positioned when installed. Engagement between the keyed-recess <NUM> and the keyed-profile <NUM> of the multi-stage stop device <NUM> may, in some embodiments, ensure or help to ensure that the multi-stage stop device <NUM> can only be installed in a single position and orientation. This may prevent or reduce the likelihood that the multi-stage stop device <NUM> is incorrectly installed and correctly position the multi-stage stop device <NUM> relative to the axis of rotation <NUM> (see also <FIG>, showing the relative position between the multi-stage stop device <NUM> and the axis of rotation <NUM>).

As another example, engagement between the keyed-recess <NUM> and the keyed-profile <NUM> of the multi-stage stop device <NUM> may beneficially transfer forces between the multi-stage stop device <NUM> and the portion of the robotic arm <NUM> to which it is attached (e.g., the first link <NUM> in the illustrated example). For example, during a collision, forces acting on the multi-stage stop device <NUM> can be transferred between the multi-stage stop device <NUM> and the first link <NUM> through contact between the multi-stage stop device <NUM> and the walls <NUM> of the keyed-recess <NUM>. This may advantageously distribute the forces that could potentially shear the fastener <NUM> if the fastener <NUM> were the only mechanism securing the multi-stage stop device <NUM> to the first link <NUM>. Thus, a system that incorporates the multi-stage stop device <NUM> and a keyed-recess <NUM> may, in some embodiments, be capable of handling higher forces than a system that does not include the keyed-recess <NUM>. Still, in some embodiments in which the forces are lower, the multi-stage stop device <NUM> may be used without a keyed-recess <NUM>.

<FIG> is a perspective view illustrating the multi-stage stop device <NUM> installed in the keyed-recess <NUM> of <FIG>. As illustrated, the frame member <NUM> is closely received within the keyed-recess <NUM> due to the corresponding nature of the keyed-profile <NUM> and the keyed-recess <NUM>. As noted above, this can beneficially ensure that the multi-stage stop device <NUM> is correctly oriented and positioned and transfer forces between the multi-stage stop device <NUM> and the first link <NUM>. Further, as illustrated, the fastener <NUM> can secure the multi-stage stop device <NUM> into the keyed-recess <NUM>. The fastener <NUM> can comprise, for example, a mechanical fastener such as a bolt.

In the illustrated embodiment, when installed, the multi-stage stop device <NUM> is positioned on the internal surface or portion <NUM> of the housing <NUM> of the first link <NUM>. Positioning the multi-stage stop device <NUM> on an internal surface or portion <NUM> of the housing <NUM> may be advantageous because it may conceal the multi-stage stop device <NUM>, improving the look of the robotic arm <NUM>. In other embodiments, the multi-stage stop device <NUM> can be positioned on an external surface or portion of the housing <NUM> of the first link <NUM> or on an internal or external surface or portion of the base <NUM>.

<FIG> is a perspective view illustrating a portion of the base <NUM> of the robotic arm <NUM> of <FIG> that includes a protruding member <NUM> configured to contact the multi-stage stop device <NUM> to limit or stop rotation of the first link <NUM> relative to the base <NUM> about the axis of rotation <NUM>. In the illustrated embodiment, the protruding member <NUM> protrudes from an internal portion or surface <NUM> of a housing <NUM> of the base <NUM>. The internal portion or surface <NUM> of the housing <NUM> may be a portion of the base <NUM> that is not visible when the robotic arm <NUM> is assembled. In some embodiments, the internal portion or surface <NUM> of the housing <NUM> may face the internal surface or portion <NUM> of the first link <NUM> when the robotic arm <NUM> is assembled (see, for example, <FIG>).

The protruding member <NUM> is positioned so as to come into contact with the first pin <NUM> and/or the second pin <NUM> of the multi-stage stop device <NUM> as the first link <NUM> rotates relative to the base <NUM>. Accordingly, if the multi-stage stop device <NUM> is positioned on an internal portion or surface of the first link <NUM>, the protruding member <NUM> can be positioned on a corresponding internal portion or surface of the base <NUM> (or vice versa). Similarly, if the multi-stage stop device <NUM> is positioned on an external portion or surface of the first link <NUM>, the protruding member <NUM> can be positioned on a corresponding external portion or surface of the base <NUM> (or vice versa). In some embodiments, the multi-stage stop device <NUM> can be positioned on an internal portion or surface of the first link <NUM>, and the protruding member <NUM> can be positioned on a corresponding external portion or surface of the base <NUM> (or vice versa).

The protruding member <NUM> can be positioned at the same distance from the axis of rotation <NUM> as the first pin <NUM> and the second pin <NUM> so that the protruding member <NUM> comes into contact with the first pin <NUM> and/or the second pin <NUM> during rotation of the first link <NUM> relative to the base <NUM>. As will be described with more detail with reference to <FIG>, the contact between the protruding member <NUM> and the first pin <NUM> and/or the second pin <NUM> limits or stops rotation of the first link <NUM> relative to the base <NUM>.

In some embodiments, for example, as illustrated, the protruding member <NUM> may comprise a bolt. In the illustrated embodiment, the bolt head protrudes from the internal surface or portion <NUM> of the base <NUM> in a position so as to contact the first pin <NUM> and/or the second pin <NUM> during rotation of the first link <NUM> relative to the base <NUM>. As shown in <FIG>, in some embodiments, the internal surface or portion <NUM> of the base <NUM> may include a plurality of positions <NUM> at which the protruding member <NUM> can be installed. For example, in <FIG>, the internal surface or portion <NUM> of the base <NUM> includes eight positions <NUM> at which the protruding member <NUM> can be installed. In the illustrated embodiment, the eight positions <NUM> comprises eight bolt holes into which the bolt can be installed. In some embodiments, other numbers of positions <NUM> (e.g., one, two, three, four, five, six, etc.) can be included. The different positions <NUM> allow the protruding member <NUM> to be installed in different locations so that the protruding member <NUM> contacts the first pin <NUM> and/or the second pin <NUM> at different rotational positions during the rotation of the first link <NUM> relative to the base <NUM>. Further, in some embodiments, more than one protruding member <NUM> can be installed so as to limit the range of rotational motion between the first link <NUM> and base <NUM>, as shown in <FIG> described below.

<FIG> is a cross-sectional view of the robotic arm <NUM> of <FIG> taken through the rotational joint <NUM> (see <FIG>) between the base <NUM> and the first link <NUM> so as to illustrate the multi-stage stop device <NUM> and protruding member <NUM> according to a first embodiment. This illustrated embodiment includes a single protruding member <NUM> as shown. As such, the first link <NUM> can rotate relative to the base <NUM> about the axis of rotation <NUM> with a rotational range <NUM> as illustrated. At the extremes of the rotational range <NUM> (illustrated with arrow heads on the dashed line) the first pin <NUM> and the second pin <NUM> come into contact with the protruding member <NUM> so as to limit and stop rotation.

<FIG> is another cross-sectional view of the robotic arm <NUM> of <FIG> taken through the rotational joint <NUM> between the base <NUM> and the first link <NUM> in an embodiment that includes the multi-stage stop device <NUM> and two protruding members <NUM> positioned as shown. In this embodiment, the rotational range <NUM> is reduced as the first link <NUM> can only rotate relative to the base <NUM> in the rotational range <NUM> between the two protruding members <NUM>.

As will be apparent to those of ordinary skill in the art upon consideration of <FIG> (as well as the disclosure generally), it is possible to adjust the rotational range <NUM> of the first link <NUM> relative to the base <NUM> by adjusting the position and number (e.g., use of one or two) protruding members <NUM>. As noted above, the protruding member(s) <NUM> can be installed in any of the possible positions <NUM>.

At each extreme of the rotational range <NUM>, one of the first pin <NUM> and the second pin <NUM> comes into contact with the protruding member <NUM>. <FIG> illustrate the function of the multi-stage stop device <NUM> when the multi-stage stop device <NUM> comes into contact with the protruding member <NUM>. <FIG> illustrate contact between the first pin <NUM> and the protruding member <NUM>. Contact between the second pin <NUM> and the protruding member <NUM> can be similar.

<FIG> illustrates the multi-stage stop device <NUM> prior to contact with the protruding member <NUM>. The multi-stage stop device <NUM> is in a default configuration prior to contact and the compressible member <NUM> is in an uncompressed state. As the first link <NUM> rotates relative to the base <NUM>, the protruding member <NUM> approaches the first pin <NUM> in the direction illustrated by the arrow.

<FIG> illustrates an example of the "first stage" of the multi-stage stop device <NUM> during contact with the protruding member <NUM>. In this example, as the protruding member <NUM> contacts the distal end of the first pin <NUM> of the multi-stage stop device <NUM>, the first pin <NUM> is driven inward, compressing the compressible member <NUM> of the multi-stage stop device <NUM>. In some embodiments, compression of the compressible member <NUM> absorbs and dissipates the force of the collision between the protruding member <NUM> and the multi-stage stop device <NUM>. The first stage of the multi-stage stop device <NUM> may be a compliant stage that occurs as the first pin <NUM> compresses the compressible member <NUM>.

<FIG> illustrates an example of the "second stage" of the multi-stage stop device <NUM> during contact with the protruding member <NUM>. In this example, the protruding member <NUM> has driven the first pin <NUM> completely in, such that the protruding member <NUM> now contacts the first sidewall <NUM> of the multi-stage stop device <NUM>. The first sidewall <NUM> serves as a hard stop, preventing further rotation of the first link <NUM> relative to the base <NUM>. The second stage of the multi-stage stop device <NUM> may be a hard stop stage that occurs when the protruding member comes into contact with the first sidewall <NUM> of the multi-stage stop device <NUM> preventing any further rotation.

The multi-stage stop device <NUM> as described herein may provide advantages not achieved may other types of mechanical stop devices. Other mechanical stop devices generally comprises only a hard stop that abruptly stops rotation. These other hard stops are often formed by direct bolt-on-bolt or bolt-on-rubber contact, which can cause significant wear to the robotic arm on which they are installed. Further, these other hard stops are often positioned on the exterior of the robotic arm, which can be disadvantageous. Finally, these other hard stops are generally positioned in a predetermined location, such that the user is unable to adjust the arm's angle of rotation.

In contrast, the multi-stage stop devices <NUM> described herein can advantageously include a first compliant stage and a second hard stop stage that can reduce wear on the robotic arm. Additionally, the multi-stage stop devices <NUM> can be positioned within the interior of the robotic arm (as in the examples described above). Finally, the multi-stage stop devices <NUM> are adjustable by moving the protruding member <NUM> to any of the available positions <NUM> (see <FIG>, <FIG>).

A multi-stage stop device as shown in <FIG> has been tested on a robotic arm <NUM> as shown in <FIG> and successfully stopped the rotation about axis <NUM> while surviving a collision at full speed and full payload. The compressible member <NUM> that was tested had a shore hardness of 75D. This, however, is only one example, and many other embodiments are possible as described above.

The foregoing description details certain embodiments of the systems, devices, and methods disclosed herein. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the systems, devices, and methods can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the disclosure should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the technology with which that terminology is associated.

It will be appreciated by those skilled in the art that various modifications and changes can be made without departing from the scope of the described technology. Such modifications and changes are intended to fall within the scope of the embodiments. It will also be appreciated by those of skill in the art that parts included in one embodiment are interchangeable with other embodiments; one or more parts from a depicted embodiment can be included with other depicted embodiments in any combination. For example, any of the various components described herein and/or depicted in the Figures can be combined, interchanged or excluded from other embodiments.

The various singular/plural permutations can be expressly set forth herein for sake of clarity.

Directional terms used herein (e.g., top, bottom, side, up, down, inward, outward, etc.) are generally used with reference to the orientation shown in the figures and are not intended to be limiting. For example, the top surface described above can refer to a bottom surface or a side surface. Thus, features described on the top surface may be included on a bottom surface, a side surface, or any other surface.

It will be understood by those within the art that, in general, terms used herein are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims can contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms.

The term "comprising" as used herein is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

Claim 1:
A multi-stage stop device (<NUM>) for a robotic arm (<NUM>), the device (<NUM>) comprising:
a frame member (<NUM>) configured to mount to one of a first link (<NUM>) and a base (<NUM>) of a robotic arm (<NUM>), wherein the first link (<NUM>) and the base (<NUM>) are connected by a rotational joint (<NUM>) such that the first link (<NUM>) rotates relative to the base (<NUM>), the frame member (<NUM>) comprising a first sidewall (<NUM>) defining a first opening (<NUM>) therethrough;
a compressible member (<NUM>) positioned within the frame member (<NUM>); and
a first pin (<NUM>) comprising a first shaft (<NUM>) extending from a first head (<NUM>) to a first distal end (<NUM>), wherein the first shaft (<NUM>) is slidably received within the first opening (<NUM>) of the first sidewall (<NUM>) and the first head (<NUM>) is positioned between the first sidewall (<NUM>) and the compressible member (<NUM>),
wherein the frame member (<NUM>) further comprises a second sidewall (<NUM>) defining a second opening (<NUM>) therethrough; and
the device (<NUM>) further comprises a second pin (<NUM>) comprising a second shaft (<NUM>) extending from a second head (<NUM>) to a second distal end (<NUM>), wherein the second shaft (<NUM>) is slidably received within the second opening (<NUM>) of the second sidewall (<NUM>), characterized in that the second head (<NUM>) is positioned between the second sidewall (<NUM>) and the compressible member (<NUM>).