U.S. patent application number 16/576069 was filed with the patent office on 2020-03-19 for determining lifting events using sensors for person lifting apparatuses.
This patent application is currently assigned to Liko Research & Development AB. The applicant listed for this patent is Liko Research & Development AB. Invention is credited to Jackie Berkebile, Susan Kayser, Sravan Mamidi, Jacob Peugh, Melissa Stancato, Derek Strassle, Neal Wiggermann, Jie Zhou.
Application Number | 20200085657 16/576069 |
Document ID | / |
Family ID | 69773723 |
Filed Date | 2020-03-19 |
View All Diagrams
United States Patent
Application |
20200085657 |
Kind Code |
A1 |
Wiggermann; Neal ; et
al. |
March 19, 2020 |
DETERMINING LIFTING EVENTS USING SENSORS FOR PERSON LIFTING
APPARATUSES
Abstract
A method of determining a lifting event of a person lifting
apparatus is provided. The method includes receiving one or more of
(i) current load information from a current measuring device that
is indicative of current drawn by an actuator operatively connected
to a lifting strap of the person lifting apparatus; (ii) strap
position information from a position sensor that is indicative of a
paid out length of the lifting strap of the person lifting
apparatus; and (iii) weight information from a weight sensor that
is indicative of a load supported by the lifting strap of the
person lifting apparatus. A computing device comprising a processor
using logic is used to identify at least one of a raising event, a
repositioning event and a lowering event based on the one or more
of the current load information, strap position information and
weight information.
Inventors: |
Wiggermann; Neal;
(Batesville, IN) ; Berkebile; Jackie;
(Baldwinville, NY) ; Strassle; Derek; (Endicott,
NY) ; Stancato; Melissa; (Syracuse, NY) ;
Zhou; Jie; (Batesville, IN) ; Mamidi; Sravan;
(Columbus, IN) ; Kayser; Susan; (Batesville,
IN) ; Peugh; Jacob; (Brookville, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liko Research & Development AB |
Lulea |
|
SE |
|
|
Assignee: |
Liko Research & Development
AB
Lulea
SE
|
Family ID: |
69773723 |
Appl. No.: |
16/576069 |
Filed: |
September 19, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62733354 |
Sep 19, 2018 |
|
|
|
62878508 |
Jul 25, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61G 7/1051 20130101;
A61G 7/1015 20130101; G01R 19/16571 20130101; A61G 7/1042 20130101;
A61G 7/1065 20130101; A61G 2203/44 20130101; A61G 7/1067 20130101;
G01G 19/50 20130101; A61G 2203/70 20130101; A61G 7/108 20130101;
G01G 19/52 20130101; A61G 2203/40 20130101; A61G 2203/10 20130101;
G01G 19/445 20130101 |
International
Class: |
A61G 7/10 20060101
A61G007/10; G01G 19/50 20060101 G01G019/50; G01R 19/165 20060101
G01R019/165 |
Claims
1. A method of determining a lifting event of a person lifting
apparatus, the method comprising: receiving one or more of (i)
current load information from a current measuring device that is
indicative of current drawn by an actuator operatively connected to
a lifting strap of the person lifting apparatus; (ii) strap
position information from a position sensor that is indicative of a
paid out length of the lifting strap of the person lifting
apparatus; and (iii) weight information from a weight sensor that
is indicative of a load supported by the lifting strap of the
person lifting apparatus; and using a computing device comprising a
processor using logic to identify at least one of a raising event,
a repositioning event and a lowering event based on the one or more
of the current load information, strap position information and
weight information.
2. The method of claim 1 comprising: receiving current load
information from the current measuring device; and using the
computing device to identify the at least one of the raising event,
the repositioning event and the lowering event based on the current
load information.
3. The method of claim 1 comprising: receiving strap position
information from a position sensor; and using the computing device
to identify the at least one of the raising event, the
repositioning event and the lowering event based on the strap
position information.
4. The method of claim 1 further comprising: receiving weight
information from the weight sensor; and using the computing device
to identify the at least one of the raising event, the
repositioning event and the lowering event based on the weight
information.
5. The method of claim 1 further comprising: receiving acceleration
information indicative of an acceleration of the person lifting
apparatus; and using the computing device to identify at least one
of the raising event, the repositioning event and the lowering
event based on the acceleration information.
6. The method of claim 1 further comprising: receiving weight
information from a weight sensor indicative of weight on the
lifting strap and saving the weight information in the memory;
receiving acceleration information that is indicative of an
acceleration of the person lifting apparatus and saving the
acceleration information in the memory; and using the computing
device to identify the at least one of the raising event, the
repositioning event and the lowering event based on the weight
information and the acceleration information.
7. The method of claim 1 further comprising: receiving a signal
from a proximity sensor indicative of location of the person
lifting device; and using the computing device to identify the
location of the person lifting device.
8. The method of claim 1 further comprising communicating
information indicative of the at least one of the raising event,
the repositioning event and the lowering event to another computing
device using a network.
9. A method of determining a lifting event of a person lifting
apparatus, the method comprising: receiving strap position
information from a position sensor that is indicative of a paid out
length of the lifting strap of the person lifting apparatus; and
using a computing device comprising a processor using logic to
identify a lifting event based on the strap position
information.
10. The method of claim 9 comprising using the computing device to
identify each of a raising event, a repositioning event and a
lowering event based on the strap position information.
11. The method of claim 9 further comprising: receiving a signal
from a proximity sensor indicative of location of the person
lifting device; and using the computing device comprising the
processor using logic to identify the location of the person
lifting device.
12. The method of claim 9 further comprising communicating
information indicative of lifting event to another computing device
using a network.
13. A person lifting system comprising: an overhead rail that is
secured to a ceiling of a room; a person lifting apparatus that is
movably connected to the overhead rail, the person lifting
apparatus comprising: a lifting strap; an actuator operative
coupled to the lifting strap for raising and lowering the lifting
strap; at least one of (i) a current measuring device configured to
provide current load information to a computing device; (ii) a
position sensor configured to provide strap position information
that is indicative of a paid out length of the lifting strap to the
computing device; and (iii) a weight sensor that is configured to
provide weight information that is indicative of a load supported
by the lifting strap; and the computing device comprising a
processor using logic saved in memory that, when executed by the
processor: receives at least one of the current load information,
the strap position information and the weight information; and
identifies at least one of a raising event, a repositioning event
and a lowering event based on the at least one of the current load
information, the strap position information and the weight
information.
14. The person lifting system of claim 13, wherein the computing
device: receives the current load information; and identifies the
at least one of the raising event, the repositioning event and the
lowering event based on the current load information.
15. The person lifting system of claim 13, wherein the computing
device: receives the strap position information; and identifies the
at least one of the raising event, the repositioning event and the
lowering event based on the strap position information.
16. The person lifting system of claim 13, wherein the computing
device: receives the weight information; and identifies the at
least one of the raising event, the repositioning event and the
lowering event based on the weight information.
17. The person lifting system of claim 13, wherein the computing
device: receives acceleration information indicative of an
acceleration of the person lifting apparatus; and identifies at
least one of the raising event, the repositioning event and the
lowering event based on the acceleration information.
18. The person lifting system of claim 13, wherein the computing
device: receives a signal from a proximity sensor indicative of
location of the person lifting device on the overhead rail; and
identifies the location of the person lifting device.
19. The person lifting system of claim 13, wherein the computing
device identifies a floor rescue based on the current load
information.
20. The person lifting system of claim 13, wherein the computing
device communicates information indicative of the at least one of
the raising event, the repositioning event and the lowering event
to another computing device using a network.
Description
CROSS-REFERENCE
[0001] This application claims the benefit of and priority to U.S.
Application No. 62/733,354, titled Person Lifting Apparatuses
Including Lifting Straps and Methods of Operation Based on Current
Draw, filed Sep. 19, 2018 and also to U.S. Application No.
62/878,508, titled Determining Lifting Events Using Sensors for
Person Lifting Apparatuses, filed Jul. 25, 2019, the details of
both of which are hereby incorporated by reference.
FIELD
[0002] The present specification generally relates to person
lifting apparatuses and, in particular, using sensors with person
lifting apparatuses for determining types of lifting events.
TECHNICAL BACKGROUND
[0003] Person lifting apparatuses, such as overhead lifts are often
used to transport patients for any number of reasons. For example,
overhead lifts may operate like a winch and include a lift motor
and a lift drum that is driven by the lift motor. A lift strap may
be coupled to the lift drum for lifting and lowering a patient when
the drum is rotated and the lift strap is either wound up onto the
lift drum or paid out from the lift drum. A sling bar device may be
connected to an end of the lift strap. The sling bar device may
include a load hook that connects to a patient lift sling.
[0004] The overhead lifts may be used for any number of
repositioning, lifting and transporting events. It can be difficult
to remotely determine a type of lifting event that occurs using the
overhead lifts. For example, lifting events may be documented and
then accessed to determine a type of lifting event after the
lifting event has already occurred. What is needed is an automated
process for determining types of lifting events.
SUMMARY
[0005] In a first aspect A1, a method of determining a lifting
event of a person lifting apparatus is provided. The method
includes receiving one or more of (i) current load information from
a current measuring device that is indicative of current drawn by
an actuator operatively connected to a lifting strap of the person
lifting apparatus; (ii) strap position information from a position
sensor that is indicative of a paid out length of the lifting strap
of the person lifting apparatus; and (iii) weight information from
a weight sensor that is indicative of a load supported by the
lifting strap of the person lifting apparatus. A computing device
comprising a processor using logic is used to identify at least one
of a raising event, a repositioning event and a lowering event
based on the one or more of the current load information, strap
position information and weight information.
[0006] A second aspect A2 includes the method of the first aspect
A1 further including receiving current load information from the
current measuring device. The computing device is used to identify
the at least one of the raising event, the repositioning event and
the lowering event based on the current load information.
[0007] A third aspect A3 includes the method of the first aspect A1
or the second aspect A2 further including receiving strap position
information from a position sensor. The computing device is used to
identify the at least one of the raising event, the repositioning
event and the lowering event based on the strap position
information.
[0008] A fourth aspect A4 includes the method of any one of the
first-third aspects A1-A3 further including receiving weight
information from the weight sensor. The computing device is used to
identify the at least one of the raising event, the repositioning
event and the lowering event based on the weight information
[0009] A fifth aspect A5 includes the method of any one of the
first-fourth aspects A1-A4 further including receiving acceleration
information indicative of an acceleration of the person lifting
apparatus. The computing device to identify at least one of the
raising event, the repositioning event and the lowering event based
on the acceleration information
[0010] A sixth aspect A6 includes the method of any one of the
first-fifth aspects A1-A5 further including receiving weight
information from a weight sensor indicative of weight on the
lifting strap and saving the weight information in the memory.
Acceleration information is received that is indicative of an
acceleration of the person lifting apparatus and saving the
acceleration information in the memory. The computing device is
used to identify the at least one of the raising event, the
repositioning event and the lowering event based on the weight
information and the acceleration information.
[0011] A seventh aspect A7 includes the method of any one of the
first-sixth aspects A1-A6 further including receiving a signal from
a proximity sensor indicative of location of the person lifting
device. The computing device is used to identify the location of
the person lifting device.
[0012] An eighth aspect A8 includes the method of any one of the
first-seventh aspects A1-A7 further including communicating
information indicative of the at least one of the raising event,
the repositioning event and the lowering event to another computing
device using a network.
[0013] In a ninth aspect A9, a method of determining a lifting
event of a person lifting apparatus is provided. The method
includes receiving strap position information from a position
sensor that is indicative of a paid out length of the lifting strap
of the person lifting apparatus. A computing device comprising a
processor using logic is used to identify a lifting event based on
the strap position information.
[0014] A tenth aspect A10 includes the method of aspect nine A9
including using the computing device to identify each of a raising
event, a repositioning event and a lowering event based on the
strap position information.
[0015] An eleventh aspect A11 includes the method of aspect nine A9
or aspect ten A10 including using the computing device to identify
each of the raising event, the repositioning event and the lowering
event based on the current load information, the weight information
and the acceleration information.
[0016] A twelfth aspect A12 includes the method of any one of the
ninth-eleventh aspects A9-A11 further including communicating
information indicative of lifting event to another computing device
using a network.
[0017] In a thirteenth aspect A13, a person lifting system includes
an overhead rail that is secured to a ceiling of a room. A person
lifting apparatus is movably connected to the overhead rail. The
person lifting apparatus includes a lifting strap and an actuator
operative coupled to the lifting strap for raising and lowering the
lifting strap. The person lifting apparatus further includes at
least one of (i) a current measuring device configured to provide
current load information to a computing device; (ii) a position
sensor configured to provide strap position information that is
indicative of a paid out length of the lifting strap to the
computing device; and (iii) a weight sensor that is configured to
provide weight information that is indicative of a load supported
by the lifting strap. The computing device includes a processor
using logic saved in memory that, when executed by the processor:
receives at least one of the current load information, the strap
position information and the weight information; and identifies at
least one of a raising event, a repositioning event and a lowering
event based on the at least one of the current load information,
the strap position information and the weight information.
[0018] A fourteenth aspect A14 includes the person lifting system
of aspect fourteen A13, wherein the computing device: receives the
current load information; and identifies the at least one of the
raising event, the repositioning event and the lowering event based
on the current load information.
[0019] A fifteenth aspect A15 includes the person lifting system of
the thirteenth aspect A13 or the fourteenth aspect A14, wherein the
computing device: receives the weight information; and identifies
the at least one of the raising event, the repositioning event and
the lowering event based on the weight information.
[0020] A sixteenth aspect A16 includes the person lifting system of
any one of the thirteenth-fifteenth aspects A13-A15, wherein the
computing device: receives the weight information; and identifies
the at least one of the raising event, the repositioning event and
the lowering event based on the weight information.
[0021] A seventeenth aspect A17 includes the person lifting system
of any one of the thirteenth-sixteenth aspects A13-A16, wherein the
computing device: receives acceleration information indicative of
an acceleration of the person lifting apparatus; and identifies at
least one of the raising event, the repositioning event and the
lowering event based on the acceleration information.
[0022] An eighteenth aspect A18 includes the person lifting
apparatus of any one of the thirteenth-seventeenth aspects A13-A17,
wherein the computing device: receives a signal from a proximity
sensor indicative of location of the person lifting device on the
overhead rail; and identifies the location of the person lifting
device.
[0023] A nineteenth aspect A19 includes the person lifting
apparatus of any one of the thirteenth-eighteenth aspects A13-A18,
wherein the computing device identifies a floor rescue based on the
current load information.
[0024] A twentieth aspect A20 includes the person lifting device of
any one of the fourteenth-nineteenth aspects A14-A19, wherein the
computing device communicates information indicative of the at
least one of the raising event, the repositioning event and the
lowering event to another computing device using a network.
[0025] Additional features of the person lifting apparatuses and
methods for operating the person lifting apparatuses described
herein will be set forth in the detailed description which follows,
and in part will be readily apparent to those skilled in the art
from that description or recognized by practicing the embodiments
described herein, including the detailed description which follows,
the claims, as well as the appended drawings.
[0026] It is to be understood that both the foregoing general
description and the following detailed description describe various
embodiments and are intended to provide an overview or framework
for understanding the nature and character of the claimed subject
matter. The accompanying drawings are included to provide a further
understanding of the various embodiments, and are incorporated into
and constitute a part of this specification. The drawings
illustrate the various embodiments described herein, and together
with the description serve to explain the principles and operations
of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a front view of an overhead person lifting
apparatus, according to one or more embodiments shown and described
herein;
[0028] FIG. 2 is a schematic view of the overhead person lifting
apparatus of FIG. 1, according to one or more embodiments shown and
described herein;
[0029] FIG. 3 is another schematic view of the overhead person
lifting apparatus of FIG. 1, according to one or more embodiments
shown and described herein;
[0030] FIG. 4A is a side view of the overhead lifting apparatus of
FIG. 1 in use, according to one or more embodiments shown and
described herein;
[0031] FIG. 4B is a front view of a sling bar device for use with
the overhead lifting apparatus of FIG. 4A, according to one or more
embodiments shown and described herein;
[0032] FIG. 5 is an exemplary plot of current load versus time for
a lifting event, according to one or more embodiments shown and
described herein;
[0033] FIG. 6 is another exemplary plot of current load versus time
for a lifting event, according to one or more embodiments shown and
described herein;
[0034] FIG. 7 is another exemplary plot of current load versus time
for a lifting event, according to one or more embodiments shown and
described herein;
[0035] FIG. 8 is another exemplary plot of current load versus time
for a lifting event, according to one or more embodiments shown and
described herein;
[0036] FIG. 9 is another exemplary plot of current load versus time
for a lifting event, according to one or more embodiments shown and
described herein;
[0037] FIG. 10 illustrates a method of using a person lifting
system, according to one or more embodiments shown and described
herein;
[0038] FIG. 11 illustrates a plot of weight versus time along with
superimposed plots of acceleration and current load, according to
one or more embodiments shown and described herein;
[0039] FIG. 12 is a diagram of a person lifting system, according
to one or more embodiments shown and described herein;
[0040] FIG. 13 is an exemplary plot of lifting strap length versus
time for a lifting event, according to one or more embodiments
shown and described herein;
[0041] FIG. 14 is another exemplary plot of lifting strap length
versus time for a lifting event, according to one or more
embodiments shown and described herein;
[0042] FIG. 15 is another exemplary plot of lifting strap length
versus time for a lifting event, according to one or more
embodiments shown and described herein;
[0043] FIG. 16 is an exemplary plot of load on a lifting strap
versus time for a lifting event, according to one or more
embodiments shown and described herein; and
[0044] FIG. 17 is another exemplary plot of load on a lifting strap
versus time for a lifting event, according to one or more
embodiments shown and described herein.
DETAILED DESCRIPTION
[0045] Reference will now be made in detail to embodiments of
person lifting apparatuses and methods of operating the same,
examples of which are illustrated in the accompanying drawings.
Whenever possible, the same reference numerals will be used
throughout the drawings to refer to the same or like parts. One
embodiment of a person lifting apparatus is schematically depicted
in FIG. 1, and is designated by the reference numeral 10. The
person lifting apparatus may generally include two lift actuators
operatively connected to accessory couplings via two lift straps,
whereby each lift actuator raises and lowers the respective
accessory coupling using the respective lift strap. The accessory
couplings connect to a device, such as a sling bar device, which,
in turn, can connect to a patient lift sling.
[0046] As two lift actuators and associated lift straps are used by
the person lifting apparatuses, monitoring of the conditions of one
of the lift actuators relative to the other of the lift actuators
may be desired. For example, if one of the lift actuators is
pulling much more current than the other of the lift actuators
under operating conditions, an imbalance condition may be present.
As will be described herein, the imbalance condition may be
indicative of patient orientation as current draw can indicate load
on the lift actuator due to patient position and weight
distribution in a patient lift sling, as an example. As used
herein, the terms "current draw" and "draw current" are used
interchangeably to refer to an amount of current being provided by
a power source under loading conditions. Various embodiments of
person lifting apparatuses and methods for operating the same will
be described herein with specific reference to the appended
drawings.
[0047] Referring to FIG. 1, the person lifting apparatus 10 is part
of an overhead patient lifting system 12 that includes one or more
rails 14 that are secured or coupled to a support surface, such as
a ceiling of a room. The person lifting apparatus 10 is movably
coupled to the rail 14 by a carriage 16. In this embodiment, the
person lifting apparatus 10 is configured to support and lift a
patient with a pair of lifting straps 18 and 20. The lifting straps
18 and 20 may each include an accessory coupling 22 and 24 located
at a free end 26 and 28 of the lifting straps 18 and 20. Sling bar
devices 30 and 32 are illustrated connected to the accessory
couplings 22 and 24. While sling bar devices 30 and 32 are
illustrated, other accessories may be coupled to the lifting straps
18 and 20 depending on the desired lifting or other support
operation. In some embodiments, a sling or harness may be coupled
to both of the sling bar devices 30 and 32 to support a person for
a person lifting and/or tilting operation. An emergency brake strap
33 may be provided that can be utilized to stop all operation of
the person lifting apparatus 10 and hold the lifting straps 18 and
20 in their current positions.
[0048] Referring to FIG. 2, the person lifting apparatus 10
includes a housing 34 and a support structure 36 that is located in
the housing 34 and supports a pair of lifting strap feeding devices
38 and 40 within the same housing 34. The lifting strap feeding
devices 38 and 40 each wind up and pay out their respective lifting
strap 18 and 20. The housing 34 includes a top 42, a bottom 44,
sides 46, 48, a front 50 and a back 52 (FIG. 1) defining an
enclosure that houses the lifting strap feeding devices 38 and 40.
A hanging bracket 54 is located at the top 42 of the housing 34 and
may be connected to the housing 34 and support structure 36. The
hanging bracket 54 may also be part of or connected to the carriage
16 (FIG. 1) and allow for rotation of the housing 34 about a
vertically oriented axis of rotation A. Rotation of the housing 34
using the carriage 16 may be effectuated manually and/or may be
motorized. Manual rotation of the housing 34 may be caused, for
example, by manually grasping one of the lifting straps 18 and 20
and/or the sling bar devices 30, 32 and applying a rotational force
to the housing 34 by pulling the lifting straps 18 and 20 and/or
the sling bar devices 30, 32. A brake or other stop mechanism may
be used to inhibit rotation of the housing 34 when desired.
[0049] As can be seen in FIG. 2, the support structure 36 includes
support components (represented by element 56, such as beams,
brackets, fasteners, etc.) that support the lifting strap feeding
devices 38 and 40. The strap feeding devices 38 and 40 generally
include housings 58 and 60, lift actuators 62 and 64 (e.g.,
motors), and drums 66 and 68 that are rotated by the lift actuators
62 and 64 to wind up and pay out the lifting straps 18 and 20. The
drums 66 and 68 may be coupled to a shaft of the lift actuators 62
and 64 and may be configured to extend and retract the lifting
straps 18 and 20 as the lift actuators 62 and 64 rotate the drums
66 and 68 in response to a user providing an input to a control
system via an input device. The strap feeding devices 38 and 40 are
supported by the support structure 36 at angles .theta..sub.1 and
.theta..sub.2 to horizontal. The support structure 36 supports the
lifting strap feeding devices 38 and 40 at the angles .theta..sub.1
and .theta..sub.2 to horizontal such that lifting strap feed out
locations 70 and 72 are not facing vertically or horizontally only,
but also face outward at an angle to both vertical and horizontal.
Such a non-horizontal and non-vertical arrangement for the lifting
strap feeding devices 38 and 40 can allow the lifting strap feeding
devices 38 and 40 to pay out the lifting straps 18 and 20 at angles
.alpha..sub.1 and .alpha..sub.2 to vertical inside the housing 34
toward the sides 46 and 48 of the housing 34.
[0050] The lifting straps 18 and 20 may release from the drums 66
and 68 at points P.sub.1 and P.sub.2 where the lifting straps 18
and 20 are substantially tangent to their respective drum 66, 68.
The lifting straps 18 and 20 are then directed over spacing rollers
74 and 76 that are spaced horizontally from the points P.sub.1 and
P.sub.2 and offset horizontally from the drums 66 and 68 thereby
increasing a horizontal spacing between the lifting straps 18 and
20 as they release from their drums 66 and 68 at points P.sub.1 and
P.sub.1 to points P.sub.3 and P.sub.4 where they release from their
spacing rollers 74 and 76. By the spacing rollers being "offset
horizontally" from the drums, it is meant that a centerline of the
spacing rollers is offset horizontally from a centerline of the
drums. The points P.sub.3 and P.sub.4 may be spaced apart
horizontally a predetermined distance D.sub.1, such as between
about 10 inches and about 30 inches. The predetermined distance
D.sub.1 depends on a number of factors including a maximum required
distance between the free ends 26 and 28 of the lifting straps 18
and 20 under operating conditions. FIG. 2 illustrates the lifting
straps 18 and 20 in a freely hanging configuration with the lifting
straps 18 and 20 not in use for a lifting operation. In the freely
hanging configuration, the lifting straps 18 and 20 hang from the
spacing rollers 74 in a vertical orientation from the spacing
rollers 74 and 76. The lifting straps 18 and 20 may extend downward
from the spacing rollers 74 and 76 and exit the housing 34 at exit
openings 78 and 80. While spacing rollers 74 and 76 are described,
various other spacing members may be used that may or may not move
or rotate.
[0051] Referring to FIG. 3, another schematic of operation of the
person lifting apparatus 10 is illustrated including the lift
actuators 62 and 64 and lifting straps 18 and 20 that are connected
to the lift actuators 62 and 64. A controller 84 is operatively
connected to the lift actuators 62 and 64 for controlling operation
of the lift actuators 62 and 64, e.g., based on a user input using
a user input device 90 (e.g., a remote control). The user input
device 90 may be operably connected to the strap feeding devices 38
and 40 that feed the lifting straps 18 and 20, as discussed above,
and/or connected to the controller 84. The user input device 90 may
include tilt controls 92 and 94. As an example, the tilt control 82
may be a clockwise tilt control that, upon actuation, causes the
strap feeding device 38 to wind up the lifting strap 18, while the
strap feeding device 40 pays out the lifting strap 20. The tilt
control 94 may be a counterclockwise tilt control that, upon
actuation, causes the strap feeding device 38 to pay out the
lifting strap 18, while the strap feeding device 40 winds up the
lifting strap 20. In other embodiments, the tilt controls 92 and 94
may only raise and lower one of the lifting straps 18 and 20 (e.g.,
to move the head up and down while leaving the legs stationary). In
some embodiments, the tilt controls 92 and 94 can be used to rotate
a person from a supine position to a sitting position, for
example.
[0052] The user input device 90 may also include up and down
controls 96 and 98 that causes both strap feeding devices 38 and 40
to operate simultaneously to raise and lower the lifting straps 18
and 20 together. While the tilt controls 92, 94 and the up and down
controls 96 and 98 are illustrated there may be other controls. For
example, there may be individual up and down controls for each of
the strap feeding devices 38 and 40. The user input device 90 may
be wired or wirelessly connected to the strap feeding devices 38
and 40. The user input device 90 may control the strap feeding
devices 38 and 40 directly, or controller 84 may receive input
signals from the user input device 90.
[0053] The user input device 90 may be dedicated to controlling the
strap feeding devices 38 and 40, such as a remote. In some
embodiments, the user input device 90 may be a personal computing
device, such as a smart phone or tablet that includes software that
can be used to control operation of the strap feeding devices.
Further, the user input device 90 and controller 84 may be
connected to the internet for remotely controlling operation of the
strap feeding devices 38 and 40.
[0054] During operation of the person lifting apparatus 10, the
strap feeding devices 38 and 40 may be operated such that an
imbalance condition is created. An imbalance condition may be due
to, for example, paying out and/or retracting one of the lifting
straps 18 and 20 an amount that causes a patient to tilt toward or
away from one of the lifting straps 18 and 20 more than another
beyond a predetermined amount. In these instances, one of the lift
actuators 38 and 40 may experience a greater load than the other of
the lift actuators 38 and 40.
[0055] Assuming the mapping from current to weight is linear,
weight can be quantified based on current measurements. Comparing
the ratio of currents pulled by the lift actuators 38 and 40 during
operation to a predetermined value can be used to determine an
imbalance condition. This predetermined value can be selected
through clinical evaluations and assessments of patient loading
using the two lifting straps 18 and 20, in order to accommodate
different patient morphologies. Any non-linearity in the
current-to-weight function may be addressed in logic using, for
example, a look-up table and interpolation.
[0056] In the illustrated example, the controller 84 may include
circuitry that reads the current being pulled by the lift actuators
38 and 40 from a power source. In some embodiments, a current
measuring device, also represented by element 84, may measure the
current from the power source and provide an output to the
controller 84. As an example, the predetermined value may be
provided as a ratio of 1.5 that is saved in memory of the
controller 84. The current measuring device may be part of the
controller 84 and/or may be separate from the controller 84.
Referring to the Table below, the first example illustrates a
balance condition with a current ratio of 1.25, below the 1.5
predetermined value. The second example illustrates an imbalance
condition with a current ratio of 1.75, above the predetermined
value.
TABLE-US-00001 TABLE Imbalance Condition Strap 1 Strap 1 Strap 2
Strap 2 Current Imbalance Weight Current Weight Current Ratio
Present? Example 1 400 lbs 10 A 320 lbs 8 A 1.25 No Example 2 140
lbs 3.5 A 80 lbs 2 A 1.75 Yes
[0057] The controller 84, upon determining an imbalance condition
exists, may take any one of a number of actions, such as to no
longer allow tilting in a direction which increases the ratio. As
another example, the controller 84 may tilt the person lifting
apparatus 10 automatically in a direction that reduces the ratio.
In some embodiments, there may be a scale of predetermined values
and the action performed by the controller 84 may depend on the
magnitude of the imbalance. Since the controller 84 can continually
monitor the current ratio, a ratio of 1.75 may be unlikely.
However, such a condition may be present, for example, when a
support is suddenly removed. While the predetermined value
described above is greater than 1, the predetermined value may
below 1, such as 0.5 or below, depending on how the calculation is
made. The controller 84 may further provide an indication to a user
that an imbalance condition is present (e.g., visual and/or
audible).
[0058] Referring to FIG. 4A, the person lifting apparatus 10 is
illustrated with its long axis 100 parallel with a direction of
travel along the rail 14. A sling 102 is illustrated connected to
the sling bar devices 30 and 32. As shown in FIG. 4B, the sling bar
devices 30, 32 (only sling bar device 30 is shown) includes a
connector 104 for coupling the sling bar device 30 to the person
lifting apparatus 10. The connector 104 is fixedly coupled to the
sling bar device 30 in FIG. 4B, although in other embodiments, the
connector 104 may be movably coupled to the sling bar device 30.
Allowing the connector 104 to move with respect to the sling bar
device 30 may help to decrease the torque forces on the connector
104 when the sling 102 is coupled to the sling bar device 30,
maintain the alignment of the sling 102, sling bar device 30, and
person lifting apparatus 10, and prevent twisting of various
components.
[0059] The sling bar device 30 includes an elongated bar 106 and
two hooks 108 coupled to the distal ends of the elongated bar 106.
In other embodiments, the sling bar device 30 may be an X-shaped
sling bar that includes two curved frame members coupled by a
middle frame member and including four support apparatus coupling
mechanisms. In still other embodiments, the sling bar may include a
U-shaped frame including two support apparatus coupling mechanisms
and a U-shaped handle extending from the frame to provide stability
to a subject being lifted. Other sling bar configurations are
contemplated. Various sling bar configurations are described in
greater detail in U.S. Pat. No. 9,757,297, entitled "Person Lift
System."
[0060] The hooks 108 include a coupling base 110 with a recessed
space 112 therein and a latch 114 configured to selectively enclose
the recessed space 112. The latch 114 is pivotally coupled to the
coupling base 110 and is configured to extend across the recessed
space 112 in a closed position and rotate towards the recessed
space 112 in an open position. In operation, when a user couples
the sling 102 to the hook 108, the user lifts the latch 114 (i.e.,
rotates the latch 114 away from the recessed space 112), to allow
the strap(s) or other portion of the sling 102 to be inserted into
the recessed space 112. When a user removes the sling 102 from the
hook 108, the user lifts the latch 114 to rotate the latch 114
toward an open position (i.e., rotates the latch 114 away from the
recessed space 112) such as with a sling strap to allow the sling
102 to be removed from the recessed space 112.
[0061] Suitable sling bars include, by way of example and not
limitation, those commercially available under the trade name
SlingGuard from Liko, HILL-ROM.RTM., or Hill-Rom Services, Inc.
(Batesville, Ind.). Additionally, it is contemplated that some
embodiments may not include a sling bar.
[0062] Current load being pulled by an actuator, whether a single
actuator or multiple actuators as described above, can be used to
determine a type of lifting event (e.g., transfer, reposition,
etc.) that is occurring in real time, or has occurred in the past
using changes in load data. FIG. 5 illustrates an example of a
filtered current load over time for a lifting event using a person
lifting apparatus from a patient sitting in a chair to the patient
lying in a bed. In this example, a single actuator for a single
strap person lifting apparatus is illustrated. The plot 200 for the
current load generally has a raising portion 202, a repositioning
portion 204 and a lowering portion 206. In this regard, there are
three distinct events--raising, repositioning and lowering--that
can be identified by the shape of the plot 200.
[0063] Upon activation of the actuator, the current load on the
actuator increases in section 208 before any lifting of the
patient. This rise in current load is due merely to activation of
the actuator. In section 210, the actuator remains unloaded for a
period of time as slack is let out of the lifting strap connected
to the actuator. Other actions can result in this section 210
having a relatively flat current load, such as inactivity or delay
in use of the actuator since time passes with no increase in
current load. The current load on the actuator increases in section
212 as the patient begins being lifted from the chair and an
increasing amount of weight of the patient is transferred from the
chair to the actuator. Because the chair may be relatively hard
compared to a bed, for example, the slope of the increase in
section 212 may be expected to be steeper than a slope seen for
other softer objects such as a bed, which will be described below.
At section 214, the actuator is fully loaded as the patient is
removed from/unsupported by the chair and lifted to a desired
height.
[0064] Once at the desired height, the actuator may be deactivated
and the lifting strap locked at the desired height for
repositioning the patient at section 216. The repositioning step
may be accomplished using the person lifting apparatus to move the
patient from the chair to a bed. With the patient in the desired
position, the actuator may again be activated, which causes a jump
in current load at section 218. Because the patient is being
lowered in the lowering portion 206, the current draw by the
actuator is generally less in the lowering portion 206 than in the
raising portion 202. At section 220, the patient is held
unsupported by the bed. At section 222, the current load increases
as the patient is lowered onto the bed. Section 224 shows the
actuator load being relatively constant for a period of time until
the actuator is deactivated.
[0065] A computing device (such as in communication with controller
84) may include memory having logic that, when executed by a
processor, identifies the raising portion 202, repositioning
portion 204 and lowering portion 206, the sections 210, 212, 214,
216, 218, 220, 222, 224 and/or certain points of interest therein.
For example, one identification point 226 may be the beginning of
section 212 when the current load rises above the current load in
unloaded section 210. Another identification point 228 may be the
end of section 212 when the current load begins to plateau
indicating the patient being fully supported. A slope of a line
passing through the identification points 226 and 228 may provide
information regarding a type of object (e.g., hard or soft) the
patient is being lifted from, as mentioned above. For example,
without wishing to be bound by theory, one might expect steeper
slopes for harder objects (e.g., chairs) than softer objects (e.g.,
beds). Other identification points 230 and 232 may be the beginning
and end of section 216, which can provide information regarding how
long a repositioning event took place. Unusually long or short
repositioning events may indicate a need to look more closely into
those events. Other identification points 234 and 236 may include
the beginning and end of section 222. There may be other points of
interest depending, for example, on the type of lifting event. For
example, identification points may be determined based on the
characteristics of a specific lifting event. Of course, how a
patient is handled and supported by an operator of the patient
lifting apparatus during a lifting process may affect the current
versus time plot characteristics.
[0066] Referring to FIG. 6, an example of a filtered current load
versus time plot for another lifting event using the person lifting
apparatus for a patient lying in bed and being transferred to a
chair is illustrated. In this example, only a raising portion 240
and a repositioning portion 242 are shown. Similar to FIG. 5, upon
activation of the actuator, the current load on the actuator
increases in section 244 before any lifting of the patient. This
rise in current load is due merely to activation of the actuator.
In section 246, the actuator remains unloaded for a period of time
as slack is let out of the lifting strap connected to the actuator.
The current load on the actuator increases in section 248 as the
patient begins being lifted from the bed and an increasing amount
of weight of the patient is transferred from the chair to the
actuator. Because the bed may be relatively soft compared to a
chair, the slope S of the increase in section 248 may be expected
to be less steep than a slope seen for other hard objects such as a
chair. At section 250, the actuator is fully loaded as the patient
is removed from/unsupported by the bed and lifted to a desired
height.
[0067] Once at the desired height, the actuator may be deactivated
and the lifting strap locked at the desired height for
repositioning the patient at section 252. The repositioning step
may be accomplished using the person lifting apparatus to move the
patient from the chair to a bed. With the patient in the desired
position, the actuator may again be activated, which causes a jump
in current load at section 254 and the lowering process begins (not
shown).
[0068] FIG. 7 illustrates another example of a filtered current
load versus time plot for another lifting event using the person
lifting apparatus for a patient lying in bed, being repositioned
and then transferred to another bed. In this example, only a
raising portion 260 and a repositioning portion 262 are shown.
Similar to FIGS. 5 and 6, upon activation of the actuator, the
current load on the actuator increases in section 264 before any
lifting of the patient. In section 266, the actuator remains
unloaded for a period of time as slack is let out of the lifting
strap connected to the actuator. The current load on the actuator
increases in section 268 as the patient begins being lifted from
the bed and an increasing amount of weight of the patient is
transferred from the chair to the actuator. Because the bed may be
relatively soft compared to a chair, the slope of the increase in
section 268 may be expected to be less steep than a slope seen for
other hard objects such as a chair.
[0069] Unlike the plot of FIG. 6, FIG. 7 illustrates a
repositioning event during the lifting of the patient at
identification point 270. The repositioning event divides section
268 into two subsections 268a and 268b where the slope S.sub.1 and
S.sub.2 changes between the subsections 268a and 268b due to the
repositioning of the patient. For example, the patient may be moved
from a supine to a seated position or vice versa). This
identification point 270 can allow identification of a
repositioning event during patient lifting. At section 272, the
actuator is fully loaded as the patient is removed from/unsupported
by the bed and lifted to a desired height.
[0070] Again, once at the desired height, the actuator may be
deactivated and the lifting strap locked at the desired height for
repositioning the patient at section 274 The repositioning step may
be accomplished using the person lifting apparatus to move the
patient from one bed to another bed. Because the patient is being
moved between beds, the transfer/repositioning time may be expected
to be less than from a bed to a chair or chair to a bed. With the
patient in the desired position, the actuator may again be
activated, which causes a jump in current load at section 276 and
the lowering process begins (not shown).
[0071] FIG. 8 illustrates another example of a filtered current
load versus time plot for another lifting event using the person
lifting apparatus for a patient lying in bed and being repositioned
for a same bed. In this example, only a raising portion 280 and a
repositioning portion 282 are shown. Similar to FIGS. 5-7, upon
activation of the actuator, the current load on the actuator
increases in section 284 before any lifting of the patient. In
section 286, the actuator remains unloaded for a period of time as
slack is let out of the lifting strap connected to the actuator.
The current load on the actuator increases in section 288 as the
patient begins being lifted from the bed and an increasing amount
of weight of the patient is transferred from the chair to the
actuator. Because the bed may be relatively soft compared to a
chair, the slope of the increase in section 288 may be expected to
be less steep than a slope seen for other hard objects such as a
chair.
[0072] Like FIG. 7, FIG. 8 illustrates a repositioning event during
the lifting of the patient at identification point 290. The
repositioning event divides section 288 into two subsections 288a
and 288b where the slope S.sub.1 and S.sub.2 changes between the
subsections 288a and 288b due to the repositioning of the patient.
At section 292, the actuator is fully loaded as the patient is
removed from/unsupported by the bed and lifted to a desired height.
Because the patient is not being transferred far, section 292 may
be relatively short in duration as the patient may not need lifted
very far off of the bed.
[0073] Again, once at the desired height, the actuator may be
deactivated and the lifting strap locked at the desired height for
repositioning the patient at section 294. The repositioning step
may be accomplished using the person lifting apparatus to move the
patient from one location in the bed to another location in the
same bed. Because the patient is being moved on the same bed, the
transfer/repositioning time may be expected to be less than, for
example, from a bed to a chair or chair to a bed. With the patient
in the desired position, the actuator may again be activated, which
causes a jump in current load at section 296 and the lowering
process begins (not shown).
[0074] FIG. 9 illustrates another example of a filtered current
load versus time plot for another lifting event using the person
lifting apparatus for a patient being lifted from a floor, such as
a floor rescue. Only a raising portion 300 and a repositioning
portion 302 are shown. Upon activation of the actuator, the current
load on the actuator increases in section 304 before any lifting of
the patient. In section 306, the actuator remains unloaded for a
period of time as slack is let out of the lifting strap connected
to the actuator. The current load on the actuator increases in
section 308 as the patient begins being lifted from the bed and an
increasing amount of weight of the patient is transferred from the
chair to the actuator.
[0075] At section 310, the actuator is fully loaded as the patient
is removed from/unsupported by the floor and lifted to a desired
height. Because the patient is being lifted from the floor, one
would expect section 310 to be relatively long in duration compared
to lifting from a chair or a bed. This length of time of section
310 can be used to identify a possible floor rescue.
[0076] While current load on the actuator is described primarily
above, other sensors can be used to identify a lifting event.
Referring to FIG. 10, in addition to monitoring current, a person
lifting apparatus 320 may include a motion sensor 322, such as an
accelerometer, and a weight sensor 412 that can be used to monitor
motion of the person lifting apparatus 320. For example, it may be
expected that a higher level of vibration may be expected with the
traverse rail 324 and person lifting apparatus 320 moving along end
rails 326 and 328 compared to the person lifting apparatus 320
moving along the traverse rail 324 alone. This detection can give
information of how the patient is being moved around within a room
330 (e.g., side-to-side or front-to-back). Further, proximity
sensors 332, 334 and 336 may be used for additional information.
For example, if sensors 332 and 334 are activated, the patient was
likely moved to a bedside chair 338 using the person lifting
apparatus. If sensors 334 and 336 are activated, the patient was
likely moved to a toilet using the person lifting apparatus 320. As
indicated above, it can also be determined whether the patient has
been lifted, transferred and lowered using the current loads on the
actuator of the person lifting apparatus 320.
[0077] Referring to FIG. 11, a weight curve 350 indicative of
weight on the lifting strap provided by the weight sensor 412, an
acceleration curve 352 indicative of acceleration (vibration) of
the person lifting apparatus 320 and a current load curve 354
indicative of current load being pulled by the actuator are
illustrated superimposed on one another versus time. FIG. 11
illustrates how the curves 350, 352 and 354 can interplay to
provide a more complete picture of a particular lifting event.
Looking at the weight curve 350, for example, in section 356, the
patient is being lifted above a bed to a predetermined height at
section 358. The corresponding section of the current load curve
354 shows a shallow slope which can indicate lifting from a soft
surface such as a bed. At section 360, legs of the patient are
rotated to a side while being manually supported thereby reducing
the weight on the lifting strap. At section 362, the patient is
held at the predetermined height while being transferred (e.g.,
pushed) to a chair. The corresponding section of the acceleration
curve shows increased vibration which can indicate lateral movement
of the person lifting apparatus 320. At section 364, the patient is
being lowered while being increasingly supported by the chair. The
corresponding section of the current load curve 354 shows a steeper
slope which can indicate lowering onto a harder surface such as a
chair.
[0078] Referring to FIG. 12, an exemplary person lifting system 400
utilizing the person lifting apparatus 320 is illustrated
schematically. The person lifting system 400 includes a
communication path 402, a processor 404, a memory module 406, the
proximity sensors 332, 334 and 336 and the person lifting apparatus
320. The person lifting apparatus 320 can include its own processor
410 that can be used to detect current load as a current measuring
device, motion sensor 322 and weight sensor 412 (e.g., a scale). As
will be discussed below, the person lifting apparatus 320 may
further include a position sensor 420 (e.g., a potentiometer) that
can be used to detect a position of lifting strap 422. For example,
the position sensor 420 may be used to determine a paid out length
of the lifting strap from a stowed or other set position. The
weight information provided by the weight sensor 412 and the
position information provided by the position sensor 420 can be
used to determine whether a lifting event is occurring and a type
of lifting event.
[0079] The processor 404, 410 may include any device capable of
executing machine-readable instructions stored on a non-transitory
computer-readable medium. The processor 404, 410 may include one or
more processors. Accordingly, each processor 404, 410 may include a
controller, an integrated circuit, a microchip, a computer, and/or
any other computing device. The person lifting system 400 may
further include network interface hardware 408. The communication
path 402 can provide data interconnectivity between the various
modules that may send and receive data. The communication path 402
may be wired and/or wireless.
[0080] The person lifting system 400 may further include the
network interface hardware 408 for communicatively coupling the
person lifting system 400 with a network 413. The network interface
hardware 408 can be communicatively coupled to the communication
path 402 and can be any device capable to transmitting and
receiving data via the network 413. The network interface hardware
408 may include antenna, modem, LAN port, Wi-Fi, mobile
communications hardware, etc. The network interface hardware 408
may include a Bluetooth.RTM. module for sending and receiving
Bluetooth communications to and from a mobile device 414.
[0081] Referring now to FIG. 13, an exemplary plot 440 of lifting
strap position over time is illustrated for a lifting event from a
bed to a chair. The plot 440 for the lifting strap position
generally has a raising portion 442, a repositioning portion 444
and a lowering portion 446. As above with current load, there are
three distinct events--raising, repositioning and lowering--that
can be identified by the shape of the plot 440.
[0082] Upon lowering of the lifting strap, a length of the lifting
strap increases in section 448, as detected by the position sensor.
In some embodiments, for example, the lifting strap may be lowered
from an initial, stowed position at t=0. At section 450, the length
of the lifting strap may remain constant for a period of time due
to connecting the lifting strap to another device, such as a sling
or repositioning sheet. After connecting the lifting strap, the
lifting strap may begin to be raised at point 452. At section 454
the lifting strap is raised until fully loaded at point 454. At
point 456, the length of the lifting strap remains constant as the
patient is transferred from the bed to the chair. Once the patient
is positioned over the chair, the lifting strap is again lowered at
point 458. At section 460, the lifting strap is lowered until the
patient is at least partially supported by the chair at point 462.
At point 464, the length of the lifting strap remains constant in
section 466 as the lifting strap is disconnected from the device.
At section 468, the lifting strap is again raised unloaded to its
initial, stowed position.
[0083] As may be appreciated, the raising portion 442 indicated a
maximum strap length that is less than that of the lowering portion
446. This disparity in length between the raising portion 442 and
the lowering portion 446 can indicate that the patient began on a
relatively raised, initial surface (e.g., a bed) than the final
surface (e.g., a chair) to which the patient was repositioned.
Compare plot 470 of FIG. 14 where a raising portion 472 is about a
same length as a lowering portion 476 after a repositioning portion
478. This substantially equivalent length of the lifting strap can
indicate a repositioning on a same surface, such as a repositioning
process of sitting up in a bed from a supine position.
[0084] Referring to FIG. 14, upon lowering of the lifting strap, a
length of the lifting strap increases in section 480, as detected
by the position sensor. At section 482, the length of the lifting
strap may remain constant for a period of time due to connecting
the lifting strap to another device, such as a sling or
repositioning sheet. After connecting the lifting strap, the
lifting strap may begin to be raised at point 484. At section 486
the lifting strap is raised until fully loaded at point 488. At
point 490, the length of the lifting strap remains constant as the
patient is transferred from the bed to the chair. In this example,
the fully loaded point 488 is relatively near the repositioning
point 490 compared to the example of FIG. 13. This may be because a
particular repositioning event may not require much lifting above
the surface, such as a repositioning in a bed. Once the patient is
repositioned, the lifting strap is again lowered at point 492. At
section 494, the lifting strap is lowered until the patient is at
least partially supported by the surface at point 496. At point
498, the length of the lifting strap remains constant in section
500 as the lifting strap is disconnected from the device. At
section 502, the lifting strap is again raised unloaded to its
initial, stowed position.
[0085] FIG. 15 illustrates a variety of variables that can be
useful in determining whether a lifting event is occurring and what
type of lifting event, such as a transfer from one surface to
another or a reposition on a single surface. The variables may be
defined as follows:
[0086] LUP.sub.start, LUP.sub.end: Lowest unloaded position (strap
connection and disconnection positions. LUP is influenced by height
of the transfer surface. A longer extension could indicate a lower
surface (e.g., a chair), while a higher surface could mean a bed or
stretcher, as examples.
[0087] .DELTA.LUP: Difference between the lowest unloaded positions
(LUP.sub.start-LUP.sub.end). .DELTA.LUP is influenced be different
heights between surfaces. A low .DELTA.LUP may indicate a
reposition in a bed or transfer from a bed to a stretcher. A higher
.DELTA.LUP suggests bed to chair transfer or similar transfer.
[0088] LLP.sub.lifting, LLP.sub.lowering: Lowest position at full
load (just after patient is fully lifted or just before patient
begins offloading). LLP may be higher if there is a need for
increased patient elevation, for example, to clear a side rail or
arm rest, which may indicate an increased likelihood of a bed to
chair transfer.
[0089] .DELTA.LLP: Difference between the lowest loaded positions
(LLP.sub.lifting-LLP.sub.lowering). Note that LUP and LLP could be
defined relative to stow height or transfer height. Like
.DELTA.LUP, .DELTA.LLP is influenced by different heights between
two surfaces and also barriers between the surfaces.
[0090] .DELTA.Slack.sub.lifting, .DELTA.Slack.sub.lowering:
Difference between the lowest unloaded position and lowest position
at full load (LUP.sub.start-LLP.sub.lifting) or
(LUP.sub.end-LLP.sub.lowering). .DELTA.Slack is influenced by the
type of sling used. For example, a repositioning sheet appears to
require more slack to connect loops (and therefore more travel
during loading) than a seated sling.
[0091] .DELTA.Tuat.sub.lowering, .DELTA.Tuat.sub.lifting:
Difference between the lowest loaded position (LLP) and the
transfer height. .DELTA.Taut is similar to .DELTA.LLP.
[0092] t.sub.prepare: Time to connect lifting straps and prepare
patient. t.sub.prepare can be highly patient dependent. Extra time
may be needed to prepare to lift some patients and longer
t.sub.prepare may indicate that a sling is being used (e.g., a
repositioning sheet may take longer to connect than other
devices).
[0093] t.sub.transfer: Time of highest static position while fully
loaded (i.e., transfer time). t.sub.transfer is influenced by the
type of movement. For example, a repositioning in bed may require
less time than a seated transfer.
[0094] As mentioned above, weight information from a weight sensor
can also be used to determine characteristics of a repositioning
event. FIG. 16, as an example, is representative of a transfer
event using a seated sling (e.g., from bed to chair) and FIG. 17,
as another example, is representative of a repositioning event
using a repositioning sling (e.g., in a bed). Comparing the plots
510 and 512, an average slope of the plot 512 using the
repositioning sling indicates a more gradual increase in load when
lifting compared to the plot 510 of the seated sling. The plot 512
also shows a more rounded curve near a beginning and an end of the
plot 512. The seated sling is more likely to shift and slip during
loading creating an irregular shape of the plot 510 compared to the
relatively smooth curve of the plot 512 of the repositioning sling.
For example a bump 514 appears in a loading section of the plot
510, which may be caused by the patient's back lifting off of the
bed followed by the posterior. Load variations may be caused by the
patient dragging on the bed if not fully lifted, such as when
transferring with a repositioning sheet. Discontinuities could be
caused by recognizable events, such as feet leaving the bed or the
caregiver lifting the feet or other body part during a transfer or
reposition event.
[0095] Additional sensors may be used to increase accuracy of type
of lifting event that is occurring or has occurred. For example,
sensors that measure lateral displacement of the person lifting
apparatus can improve accuracy in determining details of a lifting
operation. For example, a sensor providing lateral displacement
information can be used to determine a transfer operation as a
function of distance rather than as a function of time alone. For
example, a caregiver could transfer a patient laterally while
lifting/lowering the patient. In this example, using the sensor
that provides lateral displacement information may increase chances
for accuracy in identifying the transfer event. Lateral
displacement may be measured in a number of ways, such as using a
Hall-effect sensor, a non-contact ultrasonic sensor and/or a
non-contact linear/rotary variable differential transformer (LDVT
or RVDT).
[0096] The above-described person lifting systems utilize person
lifting apparatuses and can detect whether a lifting event has
occurred. In some embodiments, the person lifting systems can use
identification points to determine a type of lifting event that has
occurred. The information can be monitored locally or remotely
using computing devices.
[0097] It will be apparent to those skilled in the art that various
modifications and variations can be made to the embodiments
described herein without departing from the spirit and scope of the
claimed subject matter. Thus it is intended that the specification
cover the modifications and variations of the various embodiments
described herein provided such modification and variations come
within the scope of the appended claims and their equivalents.
* * * * *