U.S. patent number 3,756,563 [Application Number 05/203,646] was granted by the patent office on 1973-09-04 for apparatus for handling objects.
Invention is credited to Charles W. Stone.
United States Patent |
3,756,563 |
Stone |
September 4, 1973 |
APPARATUS FOR HANDLING OBJECTS
Abstract
Apparatus for handling objects is provided with controls to
automatically regulate fluid pressure in a fluid-operated hoist
under certain conditions. The apparatus includes a fluid-operated
hoist, fluid-operated, object-engaging means, and responsive means
sensitive to the pressure of the fluid of the object-engaging means
to change the pressure of the fluid supplied to the hoist. In a
preferred embodiment, the object-engaging means is embodied in a
headlight aiming instrument which adjusts the headlights of
automobiles on an assembly line. The aiming instrument includes a
vacuum cup constituting the object-engaging means, which is affixed
to the lens of the headlight. The instrument then adjusts the aim
of the headlight to a predetermined position automatically. Since
the weight of the instrument itself is accommodated in the
adjustment, the hoist is controlled to balance the weight of the
instrument until the vacuum cup is engaged with the headlight. At
that time, the responsive means will lower the pressure in the
hoist to just balance the cable and the connector which attaches
the cable to the instrument. This leaves the full weight of the
instrument itself unbalanced, as if no hoist were present. As soon
as the vacuum is released, through the responsive means the
pressure in the hoist is raised to balance the weight of the
instrument in addition to the cable and connector. The invention
can also be applied to fixtures having fluid-operated
object-engaging means. When an object is engaged by the engaging
means, the pressure in the hoist can be automatically raised to
equal or exceed the weight of the object, in addition to the
fixture, the engaging means, and the cable, to raise the object or
enable an operator to raise it. All of the pressure changes are
accomplished without any manipulation by the operator being
required.
Inventors: |
Stone; Charles W. (Garden City,
MI) |
Family
ID: |
22754764 |
Appl.
No.: |
05/203,646 |
Filed: |
December 1, 1971 |
Current U.S.
Class: |
254/331; 294/184;
254/361 |
Current CPC
Class: |
B66D
3/18 (20130101); B66D 2700/026 (20130101) |
Current International
Class: |
B66D
3/00 (20060101); B66D 3/18 (20060101); B66d
001/44 () |
Field of
Search: |
;254/168,186R
;294/64R,65,64A,64B ;214/1BS,1BT,1BH ;192/3R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Aegerter; Richard E.
Assistant Examiner: Maffei; Merle F.
Claims
I claim:
1. Apparatus for handling an object comprising a
pneumatically-operated hoist having a housing, drum means movable
in said housing, elongate flexible means connected to said drum
means, a power chamber formed in said housing, piston means
effective to move the drum means in the housing when fluid under
sufficient pressure is supplied to said chamber, a pressure
regulator for controlling pressure of fluid supplied to said
housing, fluid-responsive control means for controlling said
pressure regulator, fluid-operated engaging means for engaging an
object, said engaging means being carried by said flexible means,
means for supplying fluid to said engaging means, the fluid for
said engaging means being under one pressure when an object is
engaged and being under another pressure when the object is
disengaged, means communicating the pressure of said fluid-operated
engaging means to said fluid-responsive control means, said
fluid-responsive means causing said pressure regulator to supply
fluid under one pressure to said power chamber when the fluid
pressure of said fluid-operated engaging means is at said one
pressure, and said fluid-responsive control means causing said
pressure regulator to supply fluid under another pressure to said
power chamber when the fluid pressure of said fluid-operated
engaging means is at said another pressure.
2. Apparatus according to claim 1 characterized by said one
pressure of said engaging means being less than atmospheric
pressure and said another pressure of said engaging means being
higher than said one pressure.
3. Apparatus according to claim 1 characterized by said another
pressure to said power chamber being sufficient to balance said
fluid-operated engaging means.
4. Apparatus according to claim 1 characterized by said one
pressure to said power chamber being insufficient to balance the
weight of said fluid-operated engaging means.
5. Apparatus according to claim 1 characterized by said
fluid-responsive control means comprising a fluid-responsive valve,
said valve having a venting position for venting fluid from said
pressure regulator when said fluid-operated engaging means is at
said one pressure, and said valve having a blocking position not
venting fluid from said pressure regulator when said fluid-operated
engaging means is at said another pressure.
6. Apparatus according to claim 1 characterized by said
fluid-responsive control means comprising a fluid-responsive valve,
said valve having a blocking position to prevent venting of fluid
from said pressure regulator when said fluid-operated engaging
means is at said one pressure, and said valve having a venting
position for venting fluid from said pressure regulator when said
fluid-operated engaging means is at said another pressure.
7. Apparatus for handling an object comprising a
pneumatically-operated hoist having a housing, a drum movable in
said housing, a power chamber formed within said housing, piston
means effective to move said drum in one direction in the housing
when fluid under sufficient pressure is supplied to said chamber,
elongate flexible means connected to said drum, fluid-operated
engaging means for engaging an object, means for connecting said
engaging means and said flexible means, a fluid-controlled pressure
regulator for controlling pressure of fluid supplied to said
chamber, fluid-operated control means for regulating control fluid
for said pressure regulator, means for communicating fluid pressure
of said fluid-operated engaging means to said fluid-operated
control means, said fluid-operated control means causing said
pressure regulator to supply fluid under one pressure to said
chamber when said fluid-operated engaging means is engaged with an
object, said fluid-operated control means causing said pressure
regulator to supply fluid under another pressure to said chamber
when said fluid-operated engaging means is disengaged from the
object.
8. Apparatus according to claim 7 characterized by said one
pressure to said chamber being sufficient to offset the weight of
said elongate flexible means and said another pressure to said
chamber being sufficient to at least off set the weight of said
elongate-flexible means and said fluid-operated engaging means.
9. Apparatus according to claim 7 characterized by said one
pressure to said chamber being sufficient to enable the hoist to
offset the weight of said elongate flexible means, said
fluid-operated engaging device, and an engaged object, and said
another pressure to said chamber being sufficient to enable the
hoist to offset the weight of said elongate flexible means, and
said fluid-operated engaging means.
10. Apparatus according to claim 7 characterized by said
fluid-operated control means comprising a fluid-responsive valve
having a venting position and a blocking position.
11. Apparatus according to claim 10 characterized by said
fluid-controlled pressure regulator having a bonnet chamber
influencing the output of the pressure regulator, said
fluid-responsive valve being in communication with said bonnet
chamber.
Description
This invention relates to apparatus for handling objects and
particularly such apparatus with controls for automatically
changing the pressure in a hoist of the apparatus as
fluid-operated, object-engaging means associated therewith is
engaged with or disengaged from an object.
Basically, the invention enables a fluid-operated hoist to handle
an object with minimum manual control by an operator being
required. By way of a specific example, the invention embodies an
instrument or device for automatically aiming headlights in a new
automobile on an assembly line. The instrument employs a vacuum cup
to engage the lens of the headlight, with the headlight then being
adjusted to a predetermined position through the instrument and a
computer associated therewith. The weight of the instrument is
included in the calculations made by the computer. Consequently,
any hoist used with the instrument must not have any effect on the
weight of the instrument, when in operation. However, since the
instrument is expensive, sensitive, and delicate, a hoist is
extremely desirable to assure that the instrument will not fall
when the vacuum cup is released from the headlight lens.
In accordance with the invention, the aiming instrument is
connected through a cable to an overhead, fluid-operated hoist. The
hoist includes a pressure regulator through which hoist pressure is
controlled, with the regulator in turn being controlled by pilot
fluid pressure. A pressure-responsive valve is used to control the
pilot fluid pressure, with the valve being responsive to the
pressure in the vacuum cup of the instrument. When the vacuum is
high or the absolute pressure is low, as occurs when the vacuum cup
is attached to the headlight lens, the pressure-responsive valve
vents pilot fluid from the regulator to lower the pilot pressure
and lower the pressure of the fluid supplied through the regulator
to the hoist. This venting is adjusted so that the hoist is
effective only to balance the weight of a hoist cable and the
connector which connects the hoist cable to the headlight aiming
instrument. When the headlight adjustment is complete and fluid is
supplied to the vacuum cup to separate the instrument from the
lens, it must be assured that the instrument cannot fall.
Accordingly, the responsive valve, upon sensing the loss of vacuum,
stops the venting and thereby raises the pilot control pressure to
raise the pressure of fluid supplied through the regulator to the
hoist sufficiently to balance the weight of the instrument, thereby
to prevent any possibility of it falling.
Another embodiment of the invention can be used in an
object-handling system in which objects are engaged and picked up
with the aid of a hoist. A pressure-responsive valve automatically
places the hoist under higher pressure when a fluid-operated,
object-engaging means of a fixture is engaged with the object. In a
specific example, the responsive valve senses the pressure in a
fluid-operated clamping cylinder and causes the pressure in the
hoist to increase when a clamp or jaw operated by the cylinder
engages the object. Again, no separate operation of the hoist
controls is required on behalf of the operator, the operator merely
manipulating and actuating the fixture.
It is, therefore, a principle object of the invention to provide a
hoist with controls for automatically changing the hoist pressure
when an object is engaged.
Another object of the invention is to provide a hoist for
automatically balancing an instrument when disengaged from an
object, to prevent the possibility of the instrument falling.
A further object of the invention is to provide a hoist with a
fixture having fluid-operated, object-engaging means with controls
for increasing pressure in the hoist when an object is engaged.
Other objects and advantages of the invention will be apparent from
the following detailed description of preferred embodiments
thereof, reference being made to the accompanying drawings, in
which:
FIG. 1 is a somewhat schematic view in perspective, with parts
broken away, of a hoist, an instrument with an object-engaging
means, and controls, in accordance with the invention;
FIG. 2 is a diagrammatic view of certain hoist controls of FIG.
1;
FIG. 3 is a somewhat schematic view in cross-section of a
pressure-responsive valve constituting part of the controls of the
apparatus of FIGS. 1 & 2;
FIG. 4 is a diagrammatic view, with parts in section of a
modification of the invention, including a hoist, a fixture with a
fluid-operated, object-engaging means, and controls therefor;
and
FIG. 5 is a somewhat schematic view in cross section of a
pressure-responsive valve consitituting part of the controls of
FIG. 4.
Referring now to the drawings and specifically FIG. 1, a
pneumatically-operated hoist with which the invention can be used
is indicated at 10. The hoist shown is of the type disclosed in U.
S. Pat. No. 3,260,508, although other fluid-operated hoists can
also be used advantageously with the invention. The hoist 10
includes a power chamber 12 at one end thereof to which fluid,
commonly air, is supplied under pressure. A piston 14 forms one end
of the chamber 12 and is adjacent a rotatable drum 16 on which a
flexible member or cable 18 is carried. When air under sufficient
pressure is supplied to the chamber 12, it forces the piston 14
toward the opposite end of the hoist and moves the cable drum 16 in
the same direction. The drum 16 is supported on a ball-screw
assembly (not shown) which causes the drum to rotate as it moves
longitudinally thereof in the hoist 10, the drum rotating in a
direction to raise the cable 18. When the pressure in the chamber
12 is sufficiently low, the weight of the load carried by the cable
18 will cause the drum 16 to rotate in the opposite direction, in a
direction to lower the cable 18 and at the same time to move the
piston 14, along with the drum 16, toward the chamber end of the
hoist. Hence, when the air pressure in the hoist chamber 12 is
sufficient, it causes the cable 18 to raise any object carried by
the cable and when the pressure is sufficiently low, the cable and
object are lowered. The pressure in the chamber 12 can also be
adjusted to a predetermined value sufficient to just balance the
weight of the object to enable the operator to manipulate the
object up and down, as if it had practically no weight.
The air pressure in the chamber 12 is controlled through a
regulator control 20, which is preferably of the pilot air-control
type, as shown in U. S. Pat. No. 3,457,837.
The cable 18 is connected by a loop or other suitable connector 22
to a fluid-operated, object-engaging device or vacuum cup indicated
as 24. In this instance, the device 24 is part of a headlight
aiming instrument 26 which adjusts the headlights of automobiles on
an assembly line. The instrument 26 is a commercially-available
unit, the details of which do not constitute part of the invention.
The vacuum cup 24 is affixed to the lens of a headlight 28 mounted
in a fender 30 of an automobile proceeding along an assembly line.
With the vacuum cup in place, the instrument 26, in combination
with a computer 32 with which it is connected by conrol cables 34,
assures that the headlight is properly aimed. The instrument 26 is
extremely sensitive and its own weight is built into the
calculation made by the computer 32 through signals received
through the cables 34 from the instrument. Because the instrument
is also delicate and expensive, considerable care must be taken to
assure that it cannot fall when disengaged from the headlight 28.
Accordingly, the hoist 10 is automatically controlled so that when
the vacuum cup 24 is engaged with the lens of the headlight 28, the
pressure in the hoist chamber 12 is reduced to the point that the
hoist just balances the cable 18 and the connector 22 so that the
effective weight of the instrument 26 is the same as if no hoist
were connected to it at all. However, when the vacuum cup 24 is
disengaged from the headlight, air under higher pressure is
immediately supplied to the chamber 12 to cause the hoist to also
balance the weight of the instrument 26, preventing the possibility
of it falling.
A venturi tube 36 (FIG. 2) is built into the instrument 26 with a
line 38 connecting the throat of the venturi with the vacuum cup 24
and specifically with a central rigid back plate 40 thereof, the
vacuum cup also having an annular flexible flange 42. Air is
supplied to the venturi tube 36 through a line 44 and a valve 46
which is also built into the instrument 26. The valve has a control
button 48 which directs air from a supply line 50 either through
the line 44 or through a blow-off line 52 which also communicates
with the vacuum cup 24 through the back plate 40. When air is
supplied through the line 44, the low pressure established at the
throat of the venturi 36 establishes a vacuum in the cup 24. When
the air is diverted through the line 52, it destroys the vacuum and
enables the vacuum cup 24 to be quickly separated from or blown off
of the lens of the headlight 28. A check valve can be located in
the line 38 to prevent vacuum established in the vacuum cup 24 from
being lost in the event of failure of the air supplied through the
lines 44 and 50. This is discussed more fully in U.S. Pat. No.
3,423,119.
A pressure-responsive valve 54 is connected through a line 56 and
the line 52 to the vacuum cup 24. The valve 54 also is connected
through a line 58 with the pressure regulator control 20. Through
the combination of the control 20 and the valve 54, the pressure in
the hoist chamber 12 is regulated automatically. When the vacuum
cup 24 is not engaged with the object and specifically the lens of
the headlight 28, the pressure in the cup is substantially
atmospheric or ambient. The valve 54 is then in a blocking position
and air under higher pressure, as regulated by the control 20, is
supplied to the chamber 12. This pressure is sufficient to at least
offset the weight of the instrument 26, the connector 22 and the
cable 18 so that the instrument cannot fall. When the vacuum cup 24
is engaged with the object and specifically the lens of the
headlight 28, a vacuum is established in the vacuum cup 24 which is
transmitted through the line 56 to the valve 54. The valve then
shifts to cause venting of air through the line 58 from the control
20, with the control then supplying air under lower pressure to the
chamber 12. The pressure then is just sufficient to offset the
weight of the cable 18 and the connector 22, along with the line
56, so that the instrument 26 then functions the same as if the
hoist and its related components were not present.
The operation of the controls to achieve the above results will now
be discussed in more detail. The control 20 includes a main
regulator 60 which controls the pressure of the air supplied from a
supply line 62 through a filter 64 and through a passage 66 to the
chamber 12. The pressure of the air controlled by the main
regulator 60 is determined by a pilot air-controlled regulator 68
which receives air from the supply line 62 and supplies it through
a passage 70 past a flow-control valve 72 to a bonnet chamber 74 of
the main regulator. The pressure in the bonnet chamber 74 controls
the pressure output of the main regulator 60 with the pressure of
this chamber controlled by the pilot-controlled regulator 68 which
can be adjusted through an adjusting screw 76. The pressure in the
bonnet chamber 74 controls the pressure output of the main
regulator 60 with the pressure of this chamber controlled by the
pilot-controlled regulator 68 which can be adjusted through an
adjusting screw 76. The pressure in the bonnet chamber 74 also is
controlled through the valve 54. When this valve is in a venting
position, the chamber pressure is lower than otherwise when the
valve is in a blocking position. Thus, the hoist chamber 12 is at
higher pressure when the valve 54 is blocking and is at a lower
pressure when the valve 54 is venting.
A suitable design for the pressure-responsive valve 54 is shown
more particularly in FIG. 3. The valve 54 includes a valve body 78
having a central bore 80 in which is a sealing cylinder 82 having
appropriately placed O-ring seals 84 to contain air passing
therethrough. A spool valve 86 is located in a central passage 88
in the cylinder 82 and includes a sealing piston 90 at one end and
an enlargement 92, to serve as a guide, at the other end. a coil
spring 94 is in engagement with the end of the sealing piston 90
and urges the spool valve toward an upper block position. An inlet
98 communicates with the line 58 and an outlet 100 communicates
with a vent line 102; a recess 104 receives a fitting 106 for the
line 56. The inlet 98 and the outlet 100 communicate with the
central passage 88 through ports 108 and 110 in the cylinder 82.
Communication between the ports 108 and 110 is prevented by the
cylinder 90 of the spool valve 86 when the spool valve is urged
upwardly to the upper position by the spring 94. However, when a
sufficient vacuum is established in the vacuum cup 24, this is
communicated through the line 56 to the lower end of the
pressure-responsive valve 54. This vacuum moves the spool valve 86
downwardly against the force of the spring 94, so that air from the
line 58 can be vented through the line 102 around a small
intermediate portion 112 of the spool valve 86. In this position,
the bonnet chamber 74 of the main regulator 60 is vented through
the line 102 and the main regulator 60 thus supplies air under
lower pressure to the passage 66 and the chamber 12.
Through the adjusting screw 76 of the pilot regulator 68 and
through adjustment of the flow control valve 72, the lower pressure
in the chamber 12 can be of a value just sufficient to overcome the
weight of the hoist components connected to the instrument 26 to
enable the instrument to function as if it were free of the hoist
10. When the vacuum cup 24 is blow off the headlight 28, the
pressure at the lower end of the pressure-responsive valve 54 rises
to approximately atmospheric pressure and the spring 94 then moves
the spool valve 86 up to the blocking position so that the pressure
in the bonnet chamber 74 then returns to its previous value and air
at the higher pressure is supplied through the line 66 to the hoist
chamber 12. This hoist pressure is adjusted to be sufficient to
overcome the weight of the instrument 26 as well as the cable and
connector.
Modified load handling apparatus embodying the invention is shown
in FIGS. 4 & 5. Here the same hoist 10 can be employed or other
fluid-operated hoists can be used, with fluid pressure again
controlled by the regulator control 20. The flexible member or
cable 18 is connected by a loop 114, in this instance, to a
modified load-engaging fixture 115. The fixture 115 includes a
frame 116 having a fluid-operated, load-engaging device or means
118, including a stationary jaw 120 and a movable jaw 122 which can
engage and release an object or load 124. The jaw 122 is affixed to
an end of a piston rod 124 connected to a piston 126 in a
fluid-operated cylinder 128 which is also affixed to the frame 118
and is part of the engaging means 118. Fluid, such as air, for the
cylinder 128 can be supplied by a branch line 130 communicating
with the supply line 62, and a four-way valve 132. From here, the
air can be supplied to the blind end of the cylinder 128 through a
line 134 and to the rod end of the cylinder through lines 136 and
138.
A line 140 also is connected with the rod end of the cylinder 128
through the line 138, with the line 140 communicating with a
pressure-responsive valve 142. This valve is connected through a
line 144 with the bonnet chamber 74 of the regulator control 20,
the interior of the control 20 not being shown again in FIG. 4.
The valve 142 is shown in more detail in FIG. 5. The valve includes
a valve body 146 having a central bore 148 in which a sealing
cylinder 150 is located, the cylinder having suitably placed
O-rings 152 to prevent air leakage. A spool valve 154 is located in
a central passage 156 in the cylinder 150 and includes a sealing
piston 158 at one end and an enlargement 160 which serves at the
other end as a guide. A coil spring 162 is in engagement with the
end of the piston 158 and urges the spool valve 154 toward a lower,
blocking position. An inlet 164 in the valve body 146 communicates
with the line 144 and an outlet 166 in the body 146 communicates
with a vent line 168 with a recess 170 in the lower end of the
valve body receiving a fitting 172 for the line 140. The inlet 164
and the outlet 166 communicate with the central passage 156 of the
cylinder 150 through ports 174 and 176. Communication between the
ports 174 and 176 is prevented by the sealing cylinder 158 when the
spool valve 154 is urged downwardly to the lower position by the
spring 162. However, when sufficient pressure is established in the
rod end of the cylinder 128, this is communicated through the line
140 to the lower end of the pressure-responsive valve 142. This
pressure moves the spool valve 154 upwardly against the force of
the spring 162, so that air from the line 144 can then be vented
through the line 168 around a small intermediate portion 178 of the
spool valve 154. This lowers the pressure in the bonnet chamber of
the control 20 and reduces the pressure supplied to the power
chamber 12 of the hoist 10 so that the hoist balances only the
cable, the connector, and the fixture 115 when the object 124 is
released.
When an object is to be engaged once again, the object-engaging
means 118 is operated. Accordingly, air is supplied through the
valve 132 and the line 134 to the blind end of the cylinder 128,
causing the piston 126 to move toward the object 124 and to move
the jaw 122 into engagement with the object. At the same time, the
rod end of the cylinder 128 is vented through the valve 132 so that
pressure in the line 140 similarly drops. The spring 162 then moves
the spool valve 154 downwardly once again to block the line 144 and
enable the control 20 to again supply air at higher pressure to the
hoist 10. This pressure is adjusted so that the weight of the
fixture 115 and the object 124 is balanced or slightly exceeded,
depending on whether it is desired to have the hoist raise the
object 124 or just balance it so that an operator can manipulate it
as desired. In either case, the desired pressure change is achieved
without the necessity for the operator to manipulate any hoist
controls at all.
Various modifications of the above described embodiments of the
invention will be apparent to those skilled in the art and it is to
be understood that such modifications can be made without departing
from the scope of the invention, if they are within the spirit and
the tenor of the accompanying claims.
* * * * *