Cross Reference to Related Applications
Field
[0002] The present description relates generally to a line grab device.
Background/Summary
[0003] A line grabbing device may be a device configured to block and allow slipping of
a line at a pre-determined load. The line grabbing device may assist a user in ascending
or descending by grabbing a line via a cam or a knot. Examples of line grab devices
may include a Prusik knot, ascender devices, work positioning devices, back up devices,
and the like.
[0004] The Prusik knot, which attaches a loop of rope around a line may be the simplest
configuration of a line grab device. The Prusik knot is relatively inexpensive, but
may be vulnerable to incorrect installation and may be troublesome to set-up. Additionally,
the Prusik knot may be inefficient when sliding it along a host line due to friction
and may be difficult to reset to a desired position after being heavily loaded or
following a slip event. During the slip event, the Prusik knot may degrade the host
line and/or the lines may weld together and become difficult to separate. Furthermore,
due to a variability of peak slip forces, it may be difficult to configure a Prusik
knot for a variety of slip events.
[0005] Other examples of line grabbing device include non-levered and levered camming devices.
In each of these examples, the cams may be spring driven and toothed in varying degrees
of aggressiveness. For example, in the non-levered camming device, teeth thereof may
be relatively sharp and include an acute toothing angle. The toothed cam devices may
prevent slip between the rope and the cam in overload situations that may cause degradation
to the host rope. In the levered camming device, it may include duller teeth with
a larger toothing angle for handling higher loads. The duller teeth may decrease degradation
to a line relative to sharper teeth while the cam demands a greater amount of force
on the host line to grab it. A levering becket may be coupled to the cam to provide
a sufficient force thereto such that a desired gripping may occur.
[0006] However, the inventors have identified some issues with the approaches described
above. For example, levered camming devices may not slip under overload conditions
and degrade the host line. Some mechanical devices may automatically release the line
during an overload scenario, but these devices may not be configured to automatically
re-grab the line. Thus, there is a demand for a line grabbing device configured to
automatically slip and grab line without degrading the line due to over-rotation of
the cam.
[0007] In another example, the issues described above may be addressed by a device for grabbing
line including a cam arranged between a side plate and a chassis, wherein the cam
comprises a first slot engaged with a side plate protrusion and a second slot engaged
with a chassis protrusion
[0008] As one example, the side plate may be moved to a closed position, a first open position,
or a second open position. The cam may be moved to a closed position or an open position.
Based on an actuation of the side plate and/or the cam, operation of the device may
be modified. In some examples, the configuration of the device may simplify operation
for a user, such as allowing single-handed operation.
[0009] It should be understood that the summary above is provided to introduce in simplified
form a selection of concepts that are further described in the detailed description.
It is not meant to identify key or essential features of the claimed subject matter,
the scope of which is defined uniquely by the claims that follow the detailed description.
Furthermore, the claimed subject matter is not limited to implementations that solve
any disadvantages noted above or in any part of this disclosure.
Brief Description of the Drawings
[0010]
FIG. 1 illustrates a first view of a line grab device grabbing a line.
FIG. 2 illustrates a second view of the line grab device with an interior of a cam
of the line grab device revealed.
FIG. 3A illustrates a groove of the cam.
FIG. 3B illustrates a shape of the line in the groove.
FIGS. 4A-4E illustrate various camming angles at different positions of the cam.
FIG. 5 illustrates an alternative shape of a cam of the line grab device.
FIG. 6A illustrates a first side of the cam.
FIG. 6B illustrates a second side of the cam.
FIG. 7A illustrates a side plate of the line grab device.
FIG. 7B illustrates a chassis of the line grab device.
FIGS. 8A-8D illustrate operation of the line grab device with line being loaded into
a pulley zone.
FIGS. 9A and 9B illustrates operation of line being loaded into or unloaded from the
cam.
[0011] FIGS. 1 through 9B are shown approximately to scale, however, other dimensions may
be used if desired.
Detailed Description
[0012] The following description relates to a line grab device, as illustrated in FIG. 1.
An interior of a cam of the line grab device is illustrated in FIG. 2. The cam may
comprise a groove configured to pinch the line, as illustrated in FIGS. 3A and 3B.
FIGS. 4A through 4E illustrate various camming angles at different rotational positions
of the cam. FIG. 5 illustrates an alternative shape of a cam of the line grab device.
FIG. 6A illustrates a first side of the cam. FIG. 6B illustrates a second side of
the cam. FIG. 7A illustrates a side plate of the line grab device. FIG. 7B illustrates
a chassis of the line grab device. FIGS. 8A-8D illustrate operation of the line grab
device with line being loaded into a pulley zone. FIGS. 9A and 9B illustrates operation
of line being loaded into or unloaded from the cam.
[0013] In one embodiment of the present disclosure, a device configured to grab a line and
slip at a pre-determined load. The device may prevent overloading of a line system
and decrease a likelihood of degradation to the line due to excess tension. The device
may slip more predictably than rope knots used as a line-grabbing device or the levered
and unlevered examples described above. Additionally, set up of the device may be
faster, more reliable, and more efficient than the rope knot.
[0014] The device, in one example, is a load limiting line grab configured to slip at or
above the threshold load. The device includes a spring, an unlevered cam, and a tail.
The cam may comprise a groove including a V-shape. The groove may increase friction
applied to the line and force the cam to rotate with increased load. In response to
the upper threshold load being met or exceeded, the tail may contact the line blocking
further rotation of the cam. This may stop the cam from applying more friction to
the line, which may prevent degradation to a host line or overload of a line system.
The load overcomes the friction of the camming device and initiates a slip event.
Once the load decreases below the threshold load, the friction of the camming device
is sufficient to hold the load and re-grabs the line. The slipping and grabbing may
occur automatically without a user input. As such, the slip does not cause a complete
release of load but an upper limit of the load applied to the line.
[0015] Herein, terms cam angle and camming angle are used. A cam angle is defined as an
angle of rotation of the cam and the camming angle is defined as the angle between
a net or an average contact point of the cam (e.g., a centroid of pressure distribution)
and a line normal to the line that passes through a center of rotation of the cam.
[0016] Embodiments of the line grab device disclosed herein are illustrated and described
with a V-shaped groove cam device. In some embodiments, the line grab device may be
operated with a uniform spacing groove cam device, such as a linear shaped groove,
without departing from the scope of the present disclosure.
[0017] FIGS. 1-9B show example configurations with relative positioning of the various components.
If shown directly contacting each other, or directly coupled, then such elements may
be referred to as directly contacting or directly coupled, respectively, at least
in one example. Similarly, elements shown contiguous or adjacent to one another may
be contiguous or adjacent to each other, respectively, at least in one example. As
an example, components laying in face-sharing contact with each other may be referred
to as in face-sharing contact. As another example, elements positioned apart from
each other with only a space there-between and no other components may be referred
to as such, in at least one example. As yet another example, elements shown above/below
one another, at opposite sides to one another, or to the left/right of one another
may be referred to as such, relative to one another. Further, as shown in the figures,
a topmost element or point of element may be referred to as a "top" of the component
and a bottommost element or point of the element may be referred to as a "bottom"
of the component, in at least one example. As used herein, top/bottom, upper/lower,
above/below, may be relative to a vertical axis of the figures and used to describe
positioning of elements of the figures relative to one another. As such, elements
shown above other elements are positioned vertically above the other elements, in
one example. As yet another example, shapes of the elements depicted within the figures
may be referred to as having those shapes (e.g., such as being circular, straight,
planar, curved, rounded, chamfered, angled, or the like). Further, elements shown
intersecting one another may be referred to as intersecting elements or intersecting
one another, in at least one example. Further still, an element shown within another
element or shown outside of another element may be referred as such, in one example.
It will be appreciated that one or more components referred to as being "substantially
similar and/or identical" differ from one another according to manufacturing tolerances
(e.g., within 1-5% deviation).
[0018] Turning now to FIG. 1, it shows a device 100. In one example, the device 100 is a
line grab device. In some examples, additionally or alternatively, the device 100
may be a standalone line grab, a progress capture pulley, an ascender, a working position
device, or a backup device. An axis system 190 is shown comprising three axes, namely
an x-axis parallel to a vertical direction, a y-axis parallel to a horizontal direction,
and a z-axis parallel to a transverse direction, normal to the x- and y-axes. It will
be appreciated that the device 100 may interact with a line 104 along any of the axes
of the axis system 190.
[0019] A line path 102 may be configured to receive the line 104. In one example, the line
104 is a rope. The line path 102 may be defined by a cam 130 and a baseplate 110.
The line 104 may be selected from a plurality of lines including a variety of lengths,
thicknesses (e.g., diameters), and constructions. For example, the line 104 may include
one or more of a braided construction, a twisted construction, a liner or a mantle
surrounding a core construction, a static construction, a dynamic/flexible construction,
a synthetic material, such as nylon or polyester, and a natural material. In this
way, the device 100 may be used with a variety of lines.
[0020] The baseplate 110 may include a first surface 112, a second surface 122, and a third
surface 124. The first surface 112 may transition to the second surface 122 via a
first contoured edge 116. The second surface 122 may transition to the third surface
124 via a second contoured edge 117. The third surface 124 may transition to the first
surface 112 via a third contoured edge 118. Each of the contoured edges may be curved
with no normal angles, thereby smoothing the corners which may prevent the baseplate
110 from catching onto the line 104 or an article of clothing of a user.
[0021] The first surface 112 and the second surface 122 may be substantially planar. The
third surface 124 may comprise a curved shape. In one example, the third surface 124
may curve toward the first surface 112 and away from an eyelet 126. In one example,
the eyelet 126 may be configured to be part of a pulley including a sheave 127 supported
by a bearing. By doing this, a user may utilize a mechanical advantage system, receive
a second line, a carabiner, or other similar device. The eyelet 126 may be shaped
via the sheave 127 configured to rotate based on a movement of the user with respect
to the device extending through the eyelet 126. By doing this, an orientation of the
device 100 may be maintained as an orientation of the user may change during a descent
or an ascent.
[0022] The first surface 112 may deviate from planar adjacent to the third contoured edge
118. In one example, the first surface 112 curves away from the line path 102. Thus,
the third contoured edge 118 may extend in a direction away from the line path 102
and toward the sheave 127.
[0023] The baseplate 110 may further include a first recess 114 adjacent to the cam 130.
The first recess 114 may curve toward the second contoured edge 117, away from the
cam 130. In one example, the first recess 114 may include a conformal shape relative
to the cam 130. The first recess 114 may increase a contact area in which the line
104 is contacted by the device 100 while introducing an angular deviation of the line
path 102. Additionally, shaping the first recess 114 conformal or near conformal may
increase the contact area to an entire shape of the first recess 114, which may decrease
stress concentrations on the line 104.
[0024] The first recess 114 may include a plurality of teeth 115. The plurality of teeth
115 may be identical to one another in size and shape. In one example, the plurality
of teeth 115 extend in a direction normal to the line path 102.
[0025] The cam 130 may include a tail 132 and a protrusion 134 extending from a body 136.
The body 136 may include an axle 138 extending through an opening of a bearing 140
thereof, wherein the axle 138 may retain the cam 130 to the device 100 while the bearing
140 may allow the cam 130 to rotate in response to a load applied to the line 104.
[0026] The protrusion 134 may comprise a logarithmic shape. That is to say, the camming
angle of the cam 130 may be relatively constant when only the protrusion 134 is in
contact with the line 104. The cam 130 may deviate from logarithmic at the tail 132,
wherein the camming angle may increase due to each of the protrusion 134 and the tail
132 contacting the line 104. This may allow the cam 130 to limit the load applied
to the line 104, relative to cams following a logarithmic shape.
[0027] A second recess 111 may be along the first surface 112 between the first recess 114
and the third contoured edge 118. In one example, the positioning of the second recess
111 may correspond to a location at which a non-logarithmic portion of the cam 130
may contact the line 104 and press the line 104 against the first surface 112. In
one example, the tail 132, which is a non-logarithmic portion of the cam 130 of the
example of FIG. 1, may push the line into the second recess 111 and deflect the line
before a camming angle effect of the cam grip causes the device 100 to slip. This
may create a higher cam rotation and slip force compared to a planar baseplate or
a baseplate with only a single recess. If a back-tension is relatively high, then
tensile forces in the line may resist deflection into the second recess 111, thereby
reducing an effect on slip force compared to a planar baseplate.
[0028] A size and a shape of the second recess 111 may be adjusted to enhance the operating
conditions of the device 100. A magnitude of an effect of the second recess may be
increased by increasing a depth of the recess. Additionally or alternatively, a sensitivity
to different level of line tension on a side of the device not tensioned may be adjusted
by adjusting a length of the recess along the direction of line path. In one example,
increasing the length of the recess may decrease its sensitivity and decreasing the
length of the recess may increase its sensitivity. Herein, sensitivity may refer to
the magnitude of the effect as a function of the amount of line tension of a side
of the device not tension by the device. For example, a shorter recess may allow the
line to enter only when a lower tension is present. A longer recess may allow the
line to enter the recess when higher amounts of tension are present relative to the
shorter recess. Additionally or alternatively, the second recess 111 may include a
shape similar to the first recess 114, wherein the second recess 111 may include a
V-shaped groove arranged therein. The second recess 111 may further include, additionally
or alternatively, a texturing, such as a plurality of teeth, ribbings, or other non-linear
features.
[0029] The tail 132 may extend in a direction away from the line path 102 in the position
of the cam 130 illustrated in the example of FIG. 1. In one example, the tail 132
is raised relative to other examples of cams. The tail 132 may be configured to initiate
slip during some loads imparted on the line 104 by blocking the cam 130 from further
rotating. More specifically, the tail 132 is configured to contact the line 104 at
relatively high loads. In one example, the tail 132 may contact the line at a first
threshold load. The first threshold load may be a non-zero, positive value. Once the
load increases above a second threshold load, the cam 130 in combination with the
tail 132 may no longer grab the line 104 and the line 104 may slip. If the load decreases
below the second threshold load, then the cam 130 may re-grab the line 104. Rotation
of the cam 130 based on the load is described in greater detail with respect to FIGS.
4A to 4E. In one example, the second threshold load is a non-zero, positive value.
The second threshold load may be greater than the first threshold load. The second
threshold load may correspond to a load of the line 104 where friction generated between
the cam 130 and the line 104 is insufficient to grab the line 104. Additionally or
alternatively, the cam 130 may be configured to slip the line 104 at the second threshold
load to mitigate degradation to an outer surface of the line 104. In one example,
the slipping of the cam 130 is based on one or more of load, aperture (e.g., opening
of the line path 102), and friction.
[0030] Said another way, the tail 132 blocks rotation of the cam 130 beyond a threshold
position, initiating slip due to the friction applied by the cam 130 being less than
the load of the line 104. In this way, the rotation of the cam 130 is limited via
the line rather than the device 100 or a component thereof. The device 100 may operate
on a variety of lines 104 with different diameters or stiffnesses. The slip forces
of the device 100 are therefore more accurate, and the device 100 is more versatile.
[0031] Herein, grab refers to the line 104 being lockingly engaged with the device 100 such
that the device 100 may not travel in a direction parallel to the line. Slip may refer
to the line 104 being released by the device 100 such that the device 100 may travel
in the direction parallel to the line 104.
[0032] In some examples, the cam 130 may be configured with a spiral shape, as shown in
FIG. 5. As the cam rotates, portions of the spiral with a greater radius may contact
the line. In one example, the radius of the spiral cam may increase at a rate greater
than logarithmic, thereby causing a gradual increase in a camming angle with an increase
in cam rotation. For example, section 502 of the embodiment 500 of a device, which
may be used similarly to the device 100 of FIG. 1, may include a logarithmic shape.
Dashed line 504 illustrates a continuation of the logarithmic shape. However, the
spiral shaped cam of the embodiment 500 includes a shape with an increasing camming
angle due to an increasing radius section 506 beyond the section 502. In this way,
the increasing radius section 506 of the spiral-shaped cam of FIG. 5 may correspond
to a non-logarithmic section of the cam. That is to say, the cam angle of the device
100 of FIG. 1 and the device of embodiment 500 may comprise a relatively constant
camming angle until the tail 132 or the increased radius section 506 contacts the
line 104, wherein the camming angle may increase in a stepped manner. The cam may
be alternatively configured to include a spiral shape with a radius from a pivot point
of the cam (e.g., bearing 140) increasing in a direction of increasing rotation of
the cam 130. As portions of the spiral cam with larger radii contact the line, the
camming angle increases, such that the camming angle of the spiral shaped cam may
gradually increase throughout a rotation of the cam.
[0033] The cam 130 further comprises an outer surface 142. In the example of FIG. 1, the
outer surface 142 covers interior components of the cam 130 while further obscuring
a portion of the line 104. Turning to FIG. 2, it shows an embodiment 200 of the device
100 with the outer surface 142 of the cam 130 hidden. As such, components previously
introduced are similarly numbered in this and subsequent figures. An inner body 144,
a spring 146, and a groove 148 of the cam 130 are exposed in the example of FIG. 2.
[0034] The inner body 144 may comprise a shape similar to the shape of the outer surface
142. In one example, the inner body 144 and the outer surface 142 comprise an apostrophe
shape. The apostrophe shape may include a circular portion from which a tail or other
element extends, disrupting a shape of the circle. Additionally or alternatively,
the inner body 144 and the outer surface 142 may include a spiral shape as described
above, or they may include an elliptical shape.
[0035] The groove 148 may be cut into a shape of the cam 130 and arranged between the outer
surface 142 and the inner body 144. The groove 148 may include a plurality of teeth
150 configured to increase friction against the line 104, thereby allowing the cam
130 to grab the line 104 in response to loads below the second threshold line load.
The groove 148 and the plurality of teeth 150 are described in greater detail with
respect to FIG. 3A.
[0036] The spring 146 and spring plunger 222 may be arranged within a recess 202 of the
inner body 144. The spring 146 may be retained within the recess 202 via a spring
fastener 224 that is configured to compress the spring 146. The spring plunger 222
is configured to contact the spring on one side, and a cam axle recess 226 in the
cam axle 228. The cam axle recess 226 is accessible through a split in the cam bearing
140. This configuration may force the compressed spring 146 to create an overturning
moment about the cam axle 228, forcing the cam 130 to rotate anticlockwise towards
contact with the rope 104, as shown by arrow 290. The cam axle recess 226 is configured
to allow the cam 130 to rotate clockwise sufficiently to enable a user to load and
unload the rope 104.
[0037] The device 100 further comprises a guide 162. The guide 162 may be arranged at a
portion of the device 100 opposite to a pin 164. In one example, the pin 164 is a
protrusion. Each of the guide 162 and the pin 164 may be configured to block overturning
of the line 104. By doing this, the line 104 may not counter-rotate the cam 130.
[0038] Turning now to FIG. 3A, it shows a view 300 of the groove 148. As illustrated, the
groove 148 is shaped via interior surfaces of the outer surface 142 and inner body
144 of the cam 130. The groove 148 may increase in constriction in a direction away
from a line path (e.g., line path 102 of FIGS. 1 and 2).
[0039] The groove 148 may include the plurality of teeth 150, which may be substantially
identical to one another in size and shape. Additionally or alternatively, teeth of
the plurality of teeth 150 may be differently sized and/or shaped from one another
without departing from the scope of the present disclosure. Neighboring teeth of the
plurality of teeth 150 may be separated via a recess or other indentation. As such,
adjacent teeth may not touch one another.
[0040] The plurality of teeth 150 may comprise rounded surfaces at which the teeth may contact
the line. The rounded surface may reduce stress concentrations on the line and increase
its longevity.
[0041] In one example, the groove 148 is a V-shape. Additionally or alternatively, in some
examples, the groove 148 may include other shapes that narrow in width in a direction
away from the line path. The line, such as line 104 of FIGS. 1 and 2, may be squeezed
between surfaces of the outer surface 142 and the inner body 144 into narrower portions
of the groove 148. In this way, the line 104 may be compressed via contact with each
side of the groove 148 in addition to the first surface 112 and/or the second surface
114. That is to say, previous line grabbing devices may include two surfaces within
the groove, which may form a larger contact area relative to the contact point formed
by the groove 148. The angle of the surface of the groove 148 with respect to the
first surface 112 may increase a surface pressure relative to a cam without the groove.
[0042] FIG. 3B illustrates the triangular shape of the line 104 being pressed into the groove
148, which may further reduce a stress on an outer cover of the line by more evenly
distributing pressure. The groove 148 may provide more contact area with the line
which increases pressure while adding friction onto the line, thereby keeping the
cam 130 energized. In one example, the line is maintained in a pre-determined location,
such as a center of the cam, blocking the line from moving or biasing toward the outer
surface 142 of the inner body 144. This may further maintain more balanced loads on
the bearing 140.
[0043] In one example, the angled faces of the groove 148 may generate increased forces
due to a wedging effect of the line. The groove 148 further includes three primary
area of pressure onto the line 104, which may decrease cross-sectional distortion
and resulting stressing against a sheath of the line 104. The V-shape of the groove
148 is further configured to provide a predetermined path for the line 104 to travel
through the cam 130. This may block the line 104 from migrating side to side during
grabbing and slipping events. Side to side migration may result in a pinching of the
line and off-centered forces being applied thereto. These off-centered forces may
degrade the line while also increasing stresses on the bearing of the cam, thereby
reducing a durability of the bearing and/or increasing maintenance costs.
[0044] Turning now to FIGS. 4A, 4B, 4C, 4D, and 4E, they show various positions of the cam
130 relative to the line 104. FIG. 4A illustrates a first position 400 with a first
camming angle 402. In one example, the first position 400 is a starting position of
the cam 130 and the first camming angle 402 is between 5 and 25 degrees. Additionally
or alternatively, the first camming angle 402 may be between 15 and 25 degrees. In
one example, the first camming angle 402 may be equal to about 20 degrees.
[0045] FIG. 4B illustrates a second position 410 with a second camming angle 412. The second
position 410 may correspond to a more rotated position of the cam 130 relative to
the first position 400 of FIG. 4A. However, in one example, due to the logarithmic
shape of the protrusion 134 of the cam 130, the second camming angle 412 may be identical
to the first camming angle 402.
[0046] FIG. 4C illustrates a third position 420 with a third camming angle 422. The third
position 420 may correspond to a more rotated position of the cam 130 relative to
the second position 410 of FIG. 4B. However, in one example, due to the logarithmic
shape of the protrusion 134 of the cam 130, the third camming angle 422 may be identical
to the second camming angle 412 and the first camming angle 402. In one example, the
angle of the reaction force between the line 104 and cam remains constant, allowing
the device to continually gab the line as the load increases and the rope may deform
under pressure. The third camming angle 422, along with the first camming angle 402
and the second camming angle 412 of FIGS. 4A and 4B, may be measured based on a line
extending from a center of a pivot point of the cam 130 to a contact point and to
a surface normal to the line 104. Said another way, the camming angle is measured
as the angle between two lines, a first line connecting the contact point of the cam
on the line 104 to the center of the cam's pivot point, and a second line that runs
from the cam's pivot point and crosses the line 104 at an orthogonal angle. The camming
angle determines the relationship between the frictional force of the line on the
cam and a pressure exerted by the cam on the line.
[0047] Through each positon of the cam 130 shown in FIGS. 4A, 4B, and 4C, the tail 132 is
spaced away from the line 104. Only the protrusion 134 may contact the line 104 at
each of the first camming angle 402, the second camming angle 412, and the third camming
angle 422. However, as the cam 130 moves from the first camming angle 402 to the second
camming angle 412, the tail 132 moves closer to the line 104.
[0048] FIG. 4D illustrates a fourth position 430 with a fourth camming angle 432. The fourth
cam position 430 may correspond to a more rotated position of the cam 130 relative
to the third position 420 of FIG. 4C. The fourth camming angle 432 may correspond
to a camming angle between a first contact point 434 and a second contact point 436.
That is to say, the fourth camming angle 432 may correspond to a net or average contact
point between the first and second contact points 434, 436. The first contact point
434 may correspond to a camming angle similar to a camming angle of the first through
third positions, where the protrusion 134 contacts the line 104 at the first contact
point 434. The second contact point 436 may include a larger camming angle, between
35 to 55 degrees, relative to the camming angle corresponding to the first contact
point 436. Thus, the fourth camming angle 432, which is based on an average of the
first and second contact points 434, 436, may be between 20 and 50 degrees. In one
example, the fourth cam position 430 corresponds to a first threshold position of
the cam 130 at which the tail 132 may contact the line 104. While not illustrated
in the example of FIG. 4D, the point at which the tail 132 contacts the line (e.g.,
the second contact point 436), may further comprise pressing the line into the second
recess (e.g., second recess 111 of FIG. 1).
[0049] Thus, as the cam 130 rotates further through the positions from the first position
400 to the fourth position 430, the cam 130 contacts a greater length of the line
104. By doing this, line tension may increase and inadvertent slip may be avoided.
[0050] FIG. 4E illustrates a fifth position 440 with a fifth camming angle 442. The fifth
position 440 may correspond to a more rotated position of the cam 130 relative to
the fourth position 430 of FIG. 4D. In one example, the fifth position 440 corresponds
to a most rotated position of the cam 130. The fifth camming angle 442 may be between
50 and 60 degrees. In one example, the fifth position 440 illustrates a change of
the camming angle at a high degree of cam rotation. The camming angle shown is above
a threshold angle so that the cam is unlikely or unable to grab the line. Thus, this
amount of cam rotation may occur during fewer conditions than the camming angles of
FIGS. 4A to 4D. The spring (e.g., spring 146 of FIG. 2) may urge the cam 130 in the
direction of the line 104 such that once the line tension decreases the cam 130 may
then re-grab the line. In one example, the fifth position 440 may correspond to a
second threshold position in which the tail 132 blocks further rotation of the cam
130. In the fifth position 440, the tail 132 may be positioned to re-grab the line
104 quickly such that an amount of slip may be more controlled by a user compared
to a line grab device comprising a cam without the protrusion and the tail.
[0051] Turning now to FIG. 6A, it shows a first side 600 of the cam 130. The cam 130 includes
a first slot 610. The first slot 610 may include an arc shape. In one example, the
first slot 610 may curve and match a curvature of a circle. The first slot 610 may
be adjacent to an opening 612, wherein the opening 612 may receive a bearing, such
as bearing 140 of FIG. 1.
[0052] Turning now to FIG. 6B, it shows a second side 650 of the cam 130. The cam 130 includes
a second slot 660. The second slot 660 may be shaped identically to the first slot
610. The second slot 660 is curved and matches a curvature of a circle, such as opening
612. The second slot 660 may be identical to the first slot 610 in size. A position
of the second slot 660 on the second side 650 may be directly opposite a position
of the first slot 610 on the first side 600 along an axis (e.g., the z-axis). That
is to say, the distance and spacing of the second slot 660 relative to the opening
612 and other features of the cam 130 on the second side 650 may be identical to the
distance and spacing of the first slot 610 relative to the opening 612 and other features
of the cam 130 on the first side 600. In some examples, the slots may be positioned
at different locations than those illustrated in FIGS. 6A and 6B.
[0053] Turning now to FIG. 7A, it shows an embodiment 700 of a side plate 710 of a line
grab device, such as the device 100 of FIG. 1. The side plate 710 may include a side
plate protrusion 712 that interacts with the first slot 610 of the cam 130 shown in
FIG. 6A. The side plate protrusion 712 may slide to and between extreme ends of the
first slot 610 as the side plate 710 and/or the cam 130 is/are actuated through different
positions. The side plate 710 may cover one or more line paths of the line grab device.
For example, the side plate 710 is configured to cover or expose each of a pulley
line slot and a line path (e.g., line path 102 of FIG. 1) of the cam 130 based on
a position of the side plate 710. In one example, the side plate 710 is moveable to
a closed position, a first open position, or a second open position.
[0054] The side plate protrusion 712 may be arranged between a first side plate opening
722 and a side plate feature 724. The first side plate opening 722 may receive an
end of a fastener, such as the axle 138 of FIG. 1, for retaining the cam 130, as shown
in FIG. 1. The side plate 710 may be rotatably coupled to and/or integrated with (e.g.,
the side plate 710 and the axle 138 are a single-piece) a second extreme end of the
axle 138, wherein a chassis (e.g., chassis 760 of FIG. 7B) is fixedly coupled to a
first extreme end of the axle 138, opposite the second extreme end. The cam 130 may
be rotatably coupled to a portion of the axle 138 between the first extreme end and
the second extreme end. The side plate feature 724 may be shaped to accommodate a
chassis feature (e.g., base plate 110 of FIG. 7B). The side plate feature 724 may
be positioned between the side plate protrusion 712 and the sheave 127.
[0055] In one example, the side plate 710 may be spaced away from the sheave 127, wherein
the device may include a sheave cover 732. The sheave cover 732 may be arranged at
pulley portion of the device. The sheave cover 732 may include a curvature directed
toward the side plate 710, wherein the curvature may retain line adjacent to the sheave
127. The sheave cover 732 may be a separate piece from the side plate 710. Thus, the
sheave cover 732 may be stationary when the side plate 710 is actuated. In one example,
the side plate 710 interlocks with the sheave cover 732.
[0056] Turning now to FIG. 7B, it shows an embodiment 750 of the chassis 760 of a line grab
device, such as the device 100 of FIG. 1. The chassis 760, in combination with the
side plate 710 of FIG. 7A, may form outer surfaces of the line grab device that cover
the cam 130 and line paths of the device. Together, the chassis 760 and the side plate
710 may retain the cam 130 along with line and other features of the line grab device.
[0057] The chassis 760 may include a chassis protrusion 762. The chassis protrusion 762
may interface with the second slot 660 on the second side 650 of the cam 130, as shown
in FIG. 6B. The chassis protrusion 762 may slide to and between extreme ends of the
second slot 660. In one example, the chassis protrusion 762 may be a similar size
and shape to the side plate protrusion 712 of FIG. 7A. Each of the chassis protrusion
762 and the side plate protrusion 712 may include a cylindrical shape. During some
operating conditions, the positions of the chassis protrusion 762 and the side plate
protrusion 712 may be identical. During other operating conditions, such as when the
side plate 710 is actuated, the positions of the chassis protrusion 762 and the side
plate protrusion 712 may be different.
[0058] A pulley line slot 764 may be arranged between the sheave 127 and the baseplate 110.
Line may be inserted and passed through the pulley line slot 764 in one of the positions
of the side plate 710. The side plate 710 and the sheave cover 732 may retain the
line in the pulley line slot 764 and block debris from contacting the line, thereby
increasing a longevity thereof.
[0059] The chassis protrusion 762 and the side plate protrusion 712 may move independently
of the cam 130 or vice versa. Operation of the side plate protrusion 712 for loading
or unloading only a pulley line slot 764 or for loading or unloading a line grab portion
of the device (e.g., the cam 130) is described in greater detail below. Turning now
to FIGS. 8A, 8B, 8C, and 8D, they show embodiments of the device 100. FIG. 8A shows
an embodiment 800 of the device 100 with the side plate 710 in a closed position.
FIG. 8B shows an embodiment 825 of the device 100 with the side plate 710 rendered
transparent and in the closed position and cam 130 in a closed position. FIG. 8B shows
portions of the device 100 covered and/or blocked by the side plate 710 when in the
closed position. FIG. 8C shows an embodiment 850 of the device 100 with the side plate
710 in the closed position and the cam 130 actuated from the closed position to an
open position. FIG. 8D shows an embodiment 875 of the device 100 with the side plate
710 in a first open position and the cam 130 in a closed position. FIGS. 8A-8D are
described in tandem herein.
[0060] When the side plate 710 is in the closed position, the side plate 710 may overlap
with a portion of the sheave cover 732. In one example, the side plate 710 may overlap
with the curved portion of the sheave cover 732. The side plate 710 may be exterior
to the to the sheave cover 732 and cover the line when the line is arranged in the
pulley line slot 764.
[0061] When each of the cam 130 and the side plate 710 are in respective closed positions,
the side plate protrusion 712 is positioned between extreme ends of the first slot
610. The chassis protrusion 762 may also be positioned between extreme ends of the
first slot 610, in a position identical to the side plate protrusion 712.
[0062] In the embodiment 850, the cam 130 is actuated independently of the side plate 710
from the closed position to the open position. The side plate 710 may remain stationary
as the cam 130 is actuated from the closed position to the open position. When the
cam 130 is in the open position and the side plate 710 is in the closed position,
line may slip through the line path without being unloaded from the line path. That
is to say, the line may slip without being removed from the device 100. When the cam
130 is in the open position and the side plate 710 is in the closed position, the
side plate protrusion 712 and the chassis protrusion 762 may be pressed against a
first extreme end of the first slot 610 and the second slot 660, respectively. The
protrusions may block further articulation of the cam 130 beyond the open position.
[0063] In the embodiment 875, the side plate 710 is actuated independently of the cam 130.
In one example, the cam 130 is maintained in the closed position and the side plate
710 is actuated from the closed position to the first open position. In the first
open position, the pulley line slot 764 is exposed and line may be loaded or unloaded
from the pulley line slot 764. The first open position may include where the side
plate 710 is actuated a first predetermined distance from the closed position that
exposes the pulley line slot 764 and occludes the cam 130 and the line path (e.g.,
line path 102) thereof. Thus, in the first open position, line may not be unloaded
or loaded into the line grab portion of the device 100, while line may be loaded/unloaded
into the pulley portion of the device 100.
[0064] When the side plate 710 is in the first open position, the side plate protrusion
712 may be pressed against the second extreme end of the first slot 610. The chassis
protrusion 762 may be between the first extreme end and the second extreme end of
the second slot 660. In one example, the chassis protrusion 762 may only be actuated
from the position between the first extreme end and the second extreme end, similar
to the position of the side plate protrusion 712 in FIG. 8B, to a position pressed
against the first extreme end of the second slot 660 for all positions of the cam
130 and the side plate 710.
[0065] In one example, the side plate 710 may be actuated once a latch 801 is actuated.
The latch 801 may retain the side plate 710 in the closed position, in relation to
the chassis 760 of FIG. 7B, when in a latched position. When the latch 801 is actuated
to an unlatched position, the side plate 710 may be actuated to the first open position
or the second open position, shown in FIG. 9A. In one example, resistance from the
cam 130 may provide feedback to a user that the side plate 710 has been actuated to
the first open position, wherein actuating the side plate 710 to the second open position
includes actuating the cam 130 with the side plate 710. The latch 801 may lock the
travel restriction features of the device 100 to block movement of the side plate
710 when in the latched position. In one example, a recess or other feature may be
the travel restriction feature with which the latch 801 engages.
[0066] Turning now to FIGS. 9A and 9B, they show embodiments 900 and 950, respectively,
of the side plate 710 in a second open position and the cam 130 in the open position.
The second open position may be further from the closed position of the side plate
710 than the first open position. In one example, when the side plate 710 is actuated
from the closed position to the second open position, the side plate 710 moves through
the first open position during its actuation to the second open position.
[0067] In one embodiment, the side plate protrusion 712 is pressed against the second extreme
of the first slot 610 when the side plate 710 is in the second open position and the
cam 130 is in the open position. The chassis protrusion 662 is pressed against the
first extreme end of the second slot 660 when the cam 130 is in the open position.
[0068] In the second open position of the side plate 710 and the open position of the cam
130, line may be loaded or unloaded from the line path 102 of the grab portion of
the device. Additionally or alternatively, line may be loaded or unloaded from the
pulley line slot 764.
[0069] An example operation of the line grab device including the side plate, the chassis,
and the cam may include a user using a single hand to unlatch the side plate and actuate
the side plate from the closed position to the second open position. The cam may be
actuated from the closed position to the open position as the side plate is operated
via the single hand of the user. The side plate may be held in the second open position
and line may be loaded into a line path of the line grab device. The cam may be actuated
to its closed position, which may also move the side plate to its first open position
by the single hand of the user. As such, the line may be retained in the line path
of the cam and the user may now load line into the pulley line slot with the single
hand without worrying about the line being released from the line path of the cam.
Once the pulley line slot is loaded with line, the single hand of the user may actuate
the side plate to the closed position and retain the side plate in the closed position
via the latch. The user may then operate device and adjust the camming angle of the
cam to adjust a line slip when being suspended and/or descending via the line grab
device and line.
[0070] In one example, the device includes a retaining system with a plurality of travel
restriction features that interlock with one another to permit or block movement of
one or more components of the device. The retaining system may include grooves, recesses,
pins, protrusions, and the like, that limit actuation to a determined range. A latch
may block all features of the retaining system when in a latched position such that
the components of the device are stationary. When the latch is unlatched, the components
of the device may move via one or more of the travel restriction features moving and/or
separating from a complementary component.
[0071] An embodiment of a device configured to couple to a line includes a cam shaped to
increase a camming angle as rotation of the cam increases relative to a starting position,
wherein the camming angle is from a center of a pivot point of the cam to a net contact
point between the cam and the line and an axis orthogonal to the line. A first example
of the device further includes where the cam comprises a tail configured to contact
the line in response to the cam rotating beyond a first threshold position. A second
example of the device, optionally including the first example, further includes where
the tail blocks rotation of the cam beyond a second threshold position. A third example
of the device, optionally including one or more of the previous examples, further
includes where the cam comprises a groove, and wherein a shape of the groove increases
in width in a direction away from a pivot point of the cam. A fourth example of the
device, optionally including one or more of the previous examples, further includes
where the groove comprises a plurality of teeth configured to contact the rope. A
fifth example of the device, optionally including one or more of the previous examples,
further includes where the cam and a baseplate interact with a rope, wherein the baseplate
comprises a recess configured to support the line. A sixth example of the device,
optionally including one or more of the previous examples, further includes where
the cam includes a spring configured to initiate a turning motion of the cam, and
wherein the cam further includes a tail configured to initiate slipping of the cam
and block rotation of the cam beyond a threshold rotation.
[0072] An embodiment of a line grabbing device includes a cam with a V-shaped groove increasing
in width away from a bearing of the cam, a spring configured to overturn the cam towards
contact with a line extending through the V-shaped groove, and a non-logarithmic portion
of the cam configured to block rotation of the cam beyond a threshold rotation. A
first example of the line grabbing device further includes where the non-logarithmic
portion is a tail, wherein the tail contacts a line at the threshold rotation and
increases a camming angle of the cam. A second example of the line grabbing device,
optionally including the first example, further includes where a load of the line
decreases beyond the threshold rotation, and wherein the line slips. A third example
of the line grabbing device, optionally including one or more of the previous examples,
further includes where the cam grabs the line in response to the line load being less
than a threshold load. A fourth example of the line grabbing device, optionally including
one or more of the previous examples, further includes where the line grabbing device
grabs and slips line without a user input. A fifth example of the line grabbing device,
optionally including one or more of the previous examples, further includes where
the cam is unlevered. A sixth example of the line grabbing device, optionally including
one or more of the previous examples, further includes where the cam and a baseplate
grab a line at a contact area, and wherein the baseplate comprises a recess at the
contact area. A seventh example of the line grabbing device, optionally including
one or more of the previous examples, further includes where wherein the non-logarithmic
portion corresponds to an increased radius of a spiral shape of the cam.
[0073] The disclosure provides support for a device configured to couple to a line including
a cam arranged between a side plate and a chassis and a retaining system including
at least one protrusion positioned to slide within at least one slot. A first example
of the device further includes where the cam and the side plate are moveable independently
of one another. A second example of the device, optionally including the first example,
further includes a latch configured to retain the side plate in a closed position.
A third example of the device, optionally including one or more of the previous examples,
further includes where the side plate is actuated to a first open position when the
latch is unlatched and the cam is maintained in a closed position. A fourth example
of the device, optionally including one or more of the previous examples, further
includes where the cam is actuated to an open position when the latch is unlatched
and the side plate is actuated to a second open position. A fifth example of the device,
optionally including one or more of the previous examples, further includes where
the first open position exposes a pulley line slot and obscures a line path of the
device. A sixth example of the device, optionally including one or more of the previous
examples, further includes where the side plate interlocks with a portion of a sheave
cover.
[0074] The disclosure provides additional support for a line grab device including a chassis
comprising a line grab portion and a pulley portion, wherein a sheave is arranged
in the pulley portion and a cam is arranged in the line grab portion and a side plate
rotatably coupled to an end of an axle of the cam, wherein the side plate is configured
to actuate between a closed position, a first open position, and a second open position,
wherein the cam comprises a first slot interfaced with a side plate protrusion and
a second slot interfaced with a chassis protrusion. A first example of the line grab
device further includes where the chassis is fixedly coupled or integrated with the
axle. A second example of the line grab device, optionally including the first example,
further includes where the side plate protrusion and the chassis protrusion are arranged
between a first extreme end and a second extreme end of the first slot and the second
slot when the cam is in a closed position. A third example of the line grab device,
optionally including one or more of the previous examples, further includes where
the side plate protrusion and the chassis protrusion are pressed against the first
extreme end when the cam is in an open position and the side plate is in the closed
position. A fourth example of the line grab device, optionally including one or more
of the previous examples, further includes where the side plate protrusion is pressed
against the second extreme end of the first slot and the chassis protrusion is between
the first extreme end and the second extreme end when the cam is in a closed position
and the side plate is in the first open position. A fifth example of the line grab
device, optionally including one or more of the previous examples, further includes
where the side plate protrusion is pressed against the second extreme end of the first
slot and the chassis protrusion is pressed against the first extreme end when the
cam is in an open position and the side plate is in the second open position. A sixth
example of the line grab device, optionally including one or more of the previous
examples, further includes where the closed position of the side plate covers a pulley
line slot and a line path defined by the cam. A seventh example of the line grab device,
optionally including one or more of the previous examples, further includes where
the first open position of the side plate exposes the pulley line slot and covers
the line path. An eighth example of the line grab device, optionally including one
or more of the previous examples, further includes where the second open position
of the side plate exposes the pulley line slot and the line path. In accordance with
the disclosure this line grab device is an embodiment of the device as described herein.
[0075] The disclosure provides further support for a line grab device including a cam rotatably
coupled to an axle, a chassis fixedly coupled to the axle, and a side plate rotatably
coupled to the axle, wherein the side plate is configured to cover or expose each
of a pulley line slot and a line path of the cam based on a position of the side plate,
wherein the side plate is moveable to a closed position, a first open position, or
a second open position, wherein the cam comprises a first slot interfaced with a side
plate protrusion of the side plate and a second slot interfaced with a chassis protrusion
of the chassis. A first example of the line grab device further includes where the
side plate protrusion and the chassis protrusion comprise a cylindrical shape, and
wherein the first slot and the second slot comprise an arc shape. A second example
of the line grab device, optionally including the first example, further includes
where the cam and the side plate are rotatable independent of one another. A third
example of the line grab device, optionally including one or more of the previous
examples, further includes where a latch retains the side plate in the closed position.
In accordance with the disclosure this line grab device is an embodiment of the device
as described herein.
[0076] An embodiment of a system for a line grabbing device including a line extending through
an opening arranged between a groove of a cam and a recess of a baseplate, wherein
the groove of the cam decreases in width in a direction away from the line. A first
example of the system further includes where the groove comprises a V-shape, and wherein
the line is configured to compress into a triangular shape as it extends through the
groove. A second example of the system, optionally including the first example, further
includes where the cam is unlevered, and wherein a tail of the cam blocks rotation
of the cam greater than a threshold rotation, and wherein the cam is configured to
slip the line in response to a line tension greater than a friction applied at a position
corresponding to the threshold rotation. A third example of the system, optionally
including one or more of the previous examples, further includes where the cam grabs
the line in response to the line tension being equal to or less than the friction
applied at the position. A fourth example of the system, optionally including one
or more of the previous examples, further includes where a user provides no inputs
when the cam grabs and slips the line.
[0077] As used herein, the term "approximately" is construed to mean plus or minus five
percent of the range unless otherwise specified.
[0078] The following claims particularly point out certain combinations and sub-combinations
regarded as novel and non-obvious. These claims may refer to "an" element or "a first"
element or the equivalent thereof. Such claims should be understood to include incorporation
of one or more such elements, neither requiring nor excluding two or more such elements.
Other combinations and sub-combinations of the disclosed features, functions, elements,
and/or properties may be claimed through amendment of the present claims or through
presentation of new claims in this or a related application. Such claims, whether
broader, narrower, equal, or different in scope to the original claims, also are regarded
as included within the subject matter of the present disclosure.
1. A device configured to couple to a line, comprising:
a cam arranged between a side plate and a chassis; and
a retaining system including at least one protrusion positioned to slide within at
least one slot.
2. The device of claim 1, wherein the cam and the side plate are moveable independently
of one another and/or wherein the side plate interlocks with a portion of a sheave
cover.
3. The device of claim 1, further comprising a latch configured to retain the side plate
in a closed position.
4. The device of claim 3, wherein the side plate is actuated to a first open position
when the latch is unlatched and the cam is maintained in a closed position.
5. The device of claim 4, wherein the cam is actuated to an open position when the latch
is unlatched and the side plate is actuated to a second open position and/or wherein
the first open position exposes a pulley line slot and obscures a line path of the
device.
6. A device of claim 1, wherein said device is a line grab device, comprising:
the chassis comprising a line grab portion and a pulley portion, wherein a sheave
is arranged in the pulley portion and the cam is arranged in the line grab portion;
and
the side plate rotatably coupled to an end of an axle of the cam, wherein the side
plate is configured to actuate between a closed position, a first open position, and
a second open position; wherein
the cam comprises a first slot interfaced with a side plate protrusion and a second
slot interfaced with a chassis protrusion.
7. The line grab device of claim 6, wherein the chassis is fixedly coupled or integrated
with the axle.
8. The line grab device of claim 6, wherein the side plate protrusion and the chassis
protrusion are arranged between a first extreme end and a second extreme end of the
first slot and the second slot when the cam is in a closed position.
9. The line grab device of claim 8, wherein the side plate protrusion and the chassis
protrusion are pressed against the first extreme end when the cam is in an open position
and the side plate is in the closed position and/or wherein the side plate protrusion
is pressed against the second extreme end of the first slot and the chassis protrusion
is between the first extreme end and the second extreme end when the cam is in a closed
position and the side plate is in the first open position.
10. The line grab device of claim 8, wherein the side plate protrusion is pressed against
the second extreme end of the first slot and the chassis protrusion is pressed against
the first extreme end when the cam is in an open position and the side plate is in
the second open position.
11. The line grab device of claim 6, wherein the closed position of the side plate covers
a pulley line slot and a line path defined by the cam.
12. The line grab device of claim 11, wherein the first open position of the side plate
exposes the pulley line slot and covers the line path and/or wherein the second open
position of the side plate exposes the pulley line slot and the line path.
13. A device of claim 1, wherein said device is a line grab device, comprising:
the cam rotatably coupled to an axle;
the chassis fixedly coupled to the axle; and
the side plate rotatably coupled to the axle, wherein the side plate is configured
to cover or expose each of a pulley line slot and a line path of the cam based on
a position of the side plate, wherein the side plate is moveable to a closed position,
a first open position, or a second open position; wherein
the cam comprises a first slot interfaced with a side plate protrusion of the side
plate and a second slot interfaced with a chassis protrusion of the chassis.
14. The line grab device of claim 13, wherein the side plate protrusion and the chassis
protrusion comprise a cylindrical shape, and wherein the first slot and the second
slot comprise an arc shape, and/or wherein the cam and the side plate are rotatable
independent of one another.
15. The line grab device of claim 13, further comprising a latch retains the side plate
in the closed position.