U.S. patent number 3,805,085 [Application Number 05/365,216] was granted by the patent office on 1974-04-16 for safety system and method.
This patent grant is currently assigned to Keystone Automated Equipment, Co.. Invention is credited to Joseph J. Andrews.
United States Patent |
3,805,085 |
Andrews |
April 16, 1974 |
SAFETY SYSTEM AND METHOD
Abstract
A safety system and method for operating a machine by an
operator. The operator must initially interrupt a light beam with
both hands to activate a first switch. This initiates a first time
delay interval. Within this first time interval the operator must
strike two palm button switches before the machine will
operate.
Inventors: |
Andrews; Joseph J. (Lower
Merion Township, PA) |
Assignee: |
Keystone Automated Equipment,
Co. (Philadelphia, PA)
|
Family
ID: |
23437955 |
Appl.
No.: |
05/365,216 |
Filed: |
May 30, 1973 |
Current U.S.
Class: |
307/115; 361/177;
250/221; 361/189 |
Current CPC
Class: |
F16P
3/20 (20130101); F16P 3/144 (20130101) |
Current International
Class: |
F16P
3/00 (20060101); F16P 3/20 (20060101); F16P
3/14 (20060101); H01h 019/14 () |
Field of
Search: |
;307/92,115,116
;317/135R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; James R.
Assistant Examiner: Ginsburg; M.
Attorney, Agent or Firm: Ratner; Allan Rosenberg; Morton
J.
Claims
1. A method of safely actuating an apparatus through movement of
appendages of an operator's body by maintaining said appendages
external to a working area of said apparatus, including the steps
of:
a. actuating a first switching means displaced from said working
area with said operator appendages for initiating a first time
interval; and
b. actuating a pair of switching means displaced from said working
area and positioned adjacent said first switching means with the
same operator appendages used to actuate said first switching
within said first time
2. The method of safely actuating an apparatus as recited in claim
1 wherein said operator appendages must be continuously moved from
said first switching means to said pair of switching means in a
nonintersecting
3. The method of safely actuating an apparatus as recited in claim
1 wherein the actuating steps include the steps of contacting each
of said
4. The method of safely actuating an apparatus as recited in claim
1 wherein movement of said apparatus in said working area is
prevented when one of said pair of switching means is actuated
after said first operable
5. The method of safely actuating an apparatus as recited in claim
1 wherein movement of said apparatus in said working area is
prevented when at least one of said pair of switching means is
actuated before said first
6. A system for safely operating an apparatus by an operator,
comprising:
a. first switching means operably connected to said apparatus for
initiating a first time interval upon actuation of said first
switching means by an appendage of the body of said operator;
and
b. a pair of second switching means operatively connected to, and
positionally located with respect to said first switching means in
a manner such that the same operator body appendage must actuate
said first switching means prior to said second switching means for
operation of said apparatus, and means whereby said apparatus is
operable only when both of said second switching means are actuated
during said first time interval.
7. The system for safely operating an apparatus by an operator as
recited in claim 6 wherein said first switching means includes
light means to detect movement of said appendage of said body of
said operator for
8. A method of providing safety in activating a system by an
operator including the steps of:
a. manually actuating first switching means for initiating a first
time delay interval;
b. manually actuating second switching means within said first time
interval for initiating a second time delay interval; and
c. manually actuating a third switching means for operating said
system only when said third switching means is activated within
said first and
9. The method of providing safety in activating a system by an
operator as recited in claim 8 wherein the actuating steps include
the steps of activating each of said switching means remote from a
working area of said
10. The method of providing safety in activating a system by an
operator as recited in claim 8 wherein the actuating steps include
the steps of actuating each of said switching means consecutively,
responsive to the movement of an operator's limbs.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to the field of methods and apparatus for
providing safety to an operator of machinery.
2. Prior Art
Safety devices to prevent injury during operation of a machine are
known in the art. In some prior devices, the operator activates a
swich remote from the machine working area to operate the machine.
However, with only one switch the operator only needs one hand to
operate the machine. Therefore, the operator may carelessly stick
the other hand or another part of his body in the machine working
area during operation, possibly causing serious injury. Operators
have been known to jam the single switch in an activated operating
mode. This causes continuous action of the machine resulting in an
increased possibility of injury.
In other prior devices, the operator activates a pair of switches
in order to operate the apparatus. However, the operator may use
one hand to consecutively activate each switch, allowing one hand
to remain free. The free hand then may be injured in the machine
working area.
Other devices using two switches mounted remote from the working
area are time delay connected. Each switch must be activated within
a predetermined time of the other in order to operate the machine.
If the time delay is short enough, the operator theoretically must
use both hands to operate the machine. However, in their desire to
increase machine productivity, operators can make a device which
when held in one hand is capable of striking both switches
simultaneously. This leaves one hand free wich may be caught in the
working area of the machine during operation.
In other prior devices, the working area of a machine may be
protected by a guard during the machine operating cycle. However,
such guards are often removed by the operators because it is
sometimes a cumbersome task to insert the working piece around the
guard. When a guard is placed in combination with two machine
activating switches, both switches may still be activated by a
device held in one hand of the operator, thus leaving one hand of
the operator free which may result in injury.
SUMMARY OF THE INVENTION
A method of safely actuating a power operated machine through
movement of an operator's hand by maintaining the operator's hands
external to a working area of the machine. A first switching
mechanism displaced from the working area is actuated by the
operator's hands for initiating a first time interval. A pair of
switching mechanisms displaced from the working area and positioned
adjacent to the first switching mechanism is then actuated by the
operator's hands within the first time interval for operating the
apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective drawing of a section of an apparatus
showing the safety system mounted thereon;
FIG. 2 is a perspective blow-up view of an operator's hand passing
through a light operated switch prior to the striking of a palm
button; and,
FIG. 3 is an electrical schematic diagram of the safety system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2, there is shown a press or other
power operated machine 10 which may only be operated by use of palm
buttons 12, 14 in combination with photooptic devices 16, 18 within
a predetermined time interval. The purpose of safety device 22,
shown schematically in FIG. 3, is to prevent an operator from
inserting his hands 11 or other parts of the body within work area
20 when machine 10 is operational. Additionally, sonic or laser
mechanisms 21 prevent operation of system 10 when other portions of
the operator's body come dangerously close to work area 20.
In general, the operator to actuate system 10 must pass his hands
through light paths between 16, 16' and 18, 18.varies.. The
breaking of at least one light path initiates a time interval
during which machine 10 may be operated. However, operation can
only be established by also striking or otherwise closing palm
buttons 12, 14 during the light path initiated time interval.
As will later be described in detail, four points of contact must
be made before machine 10 will cycle. The points of contact are
controlled by time delay relays on each point which may be set from
a time of zero to a maximum time interval determined by the
particular relay circuit being used. If anyone of the four points
is activated without the other cooperative points, safety device 22
will automatically lock machine 10 and not permit operation. The
operator must then remove his hands and begin the activation
process again.
Both appendages which includes hands or limbs of the operator must
consecutively interrupt light path 56 and within a predetermined
time interval palm buttons 16, 18. Fiber-optic devices 16, 18 have
a first time delay interval associated with them that allow
operation of machine 10 only when palm buttons 16, 18 are pressed.
Each of buttons 16, 18 has a respective second and third time
interval delay within which time one switch 16 or 18 must be
actuated with respect to the other. This is conditionally based on
the fact that both of switches 16 and 18 must be actuated within
the first time interval delay defined from the interruption of
light path 56.
The time delay for each switch mechanism may be adjusted over a
range dependent on the particular time delay relay being used. As
an example, assume that fiber optics device relay is set for half a
second and devices 16, 18 are set for a quarter of a second. Then
the operator has a total time of one half a second to pass his
hands 11 through light paths 56 and depress both palm buttons 12,
14. Additionally, each of palm buttons 12, 14 must be depressed
within one quarter of a second of each other in order to operate
machine 10.
FIG. 3 is an electrical schematic diagram of safety device 22 in
line with power operated machine 10. In operation, motor disconnect
switch 24 is engaged in a normally closed position as is shown.
This closes motor switch 26 which is in line with motor starter
relay 28. This in turn closes normally open motor start switch
23.
However, the apparatus system motor may not be activated until
instantaneous start switch 30 is closed. This activates relay 32
which is connected to nodal line points 34, 36, 38, and 40. Relay
32 closes relay switch 25, thereby providing a closed electrical
path from node 27 through stop switch 29, normally closed sonic or
laser switch 31, motor start switch 23 and relay switch 25. Start
switch 30 then returns to its normally open state, however, relay
32 remains actuated through the now closed path from node 27 to
relay 32. It should be noted that when the operator's body
intersects the path between mechanisms 21, shown in FIG. 1, switch
31 is opened. This breaks the electrical path to relay 32 and
apparatus 10 will not operate irrespective of the fact that the
operator intersects light beams 54, 56 and presses palm buttons 12,
14 in the prescribed time intervals. Additionally, actuation of
relay 32 closes normally open motor switch 42 as well as switch 44.
Further photo-optic power input switch 48 is closed providing power
to photo-optic unit 50. With motor switches 26 and 42 closed, the
motor of machine system 10 is activated. In order to show that the
motor has been activated, light 46 being electrically connected to
relay 32 at node 34 is turned on. Actuation of light 46 provides a
visual manifestation that motor starter 28 has been actuated and
that operation of safety device 22 will ensure cycling of apparatus
system 10.
As has been described, the basic object of safety device 22 is to
permit cycling of machine 10 only when the operator's body is out
of work area 20. In order to accomplish this, the operator must
activate both sets of switches 16, 18 and 12, 14 within a
predetermined time interval. When the two sets of switches are
activated in the prescribed time interval, machine 10 is energized
and may pass through a cycle of operation. Energization essentially
consists of closing switches 62, 64, 66, 68, 70 and 72 at one point
in time such that a continuous current passes from node 52 to 38.
The following state table provides a time-line base showing the
condition of each switch at each point in the system operating
process. ##SPC1##
The safety device state table is explained in relation to schematic
FIG. 3 and electrical time-line flow in the following paragraphs.
Initially, the operator passes his hands through displaced light
paths 54, 56 of photo-optic unit 50. This closes switch 58 which
activates time delay relay 60. Time delay relay 60 is connected to
optic switches 62 and 64. At an initial time, switch 64 is closed
and switch 62 is open. Once beams 54 and 56 have been interrupted,
switch 62 is moved to a closed position. thus completing a portion
of the circuit between nodal points 52 and 38. Time delay relay 60
maintains switch 64 in a closed position for a predetermined time
interval between time lines B and D on the state diagram. The
operator must now close switches 70 and 66 during this time
interval or switch 64, responsive to time delay relay 60, will open
driving safety device 22 to a de-energized state and breaking the
circuit between nodes 52 and 38 analagous to a condition shown in
time-line E of the state table.
The operator must now close switches 70 and 66 within the time
interval defined by time delay relay 60. Assume the operator
strikes palm button 14 first (time-line C of the state table). This
actuates timer relay 74 which is connected to switches 70, 72.
Immediately, switch 70 is closed completing another portion of the
circuit between nodal points 52 and 38. Switch 72 is thus
maintained in a closed position throughout a time interval defined
by time delay relay 74. At the conclusion of this time interval,
switch 72 will open as is shown in time-line F of the state table.
Once switch 72 is open, irrespective of the condition of any other
switch conditions, apparatus system is deenergized.
Finally, the operator strikes palm button 12 which is connected to
time delay relay 76. This has the effect of instantaneously closing
switch 66 and maintaining switch 68 in a close state for a
predetermined time interval. Once switch 66 has been closed, a
continuous electrical path is now achieved between nodes 52, 38 and
the current flow actuates machine 10 through an operating cycle. In
this state, power operated machine 10 is energized, where all
switches 62, 64, 66, 68, 70 and 72 are closed (shown in time-line E
of the state table).
When machine 10 has reached a predetermined point in its cycle,
timers 60, 74 and 76 are reset to an initial condition. Further,
switches 62, 64, 66, 68, 70 and 72 are reset to the initial
condition shown as time-line A of the state table. The resetting of
the relay and switch elements may be accomplished by a cam reset or
like technique well known in the art. In this way only one cycle of
system 10 can be achieved by the operator without the necessity of
having to begin the time-line operations detailed in the state
table.
Although machine 10 is dependent on safety device 22 for a cycling
operation, the machine may be moved through only a portion of a
cycle by using jog switches 78. In this mode of operation,
disconnect switch 24 may be positioned to a manual setting whicn in
turn closes jog manual switch 80. This opens motor switch 26 and
closes manual switch 82, In this way open relay switch 42 is
bypassed and motor starter 28 is actuated. Further normally closed
operation switch 84 is opened and manual switch 86 is closed. As is
seen when jog switches 78 are closed, current flows in continuous
fashion to node 38 providing actuation of machine 10.
Photo-optic device 50 and sonic or laser mechanism 21 mounted on
machine 10 are well known in the art. One type of optic device 50
which has been used successfully is Model 32 - 37.intg.15
manufactured by Bausch & Lomb, Inc. One type of sonic device 21
is manufactured by Asco Fluidic Controls MOdel 6090165.
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