Note: Descriptions are shown in the official language in which they were submitted.
4~
This invcntion relates to a hand-held pneurnatic
hydraulic power unit that may be used for setting rivets,
shearing, forming, punching, etc.; this disclosure relating
to i.s use as a rivetinq tool.
While hand-held riveting tools are well known, the
tool of the subject invention incorporates certain features
which provide advantages over known tools of the prior art.
More particularly, the tool of the subject invention
eliminates the need for a separate hydraulic power unit for
delivery of pressurized hydraulic medium to the tool, thus,
among other things, avoiding loss of power in fluid conduc-
ting hoses associated with such an arrangement.
The tool of the subject invention can be of lighter
weight than a pneumatic hand-held riveting tool of the same
maximum force riveting capacity.
Another feature of the tool of the present invention
is a throttle valve arrangement wherein the rivet setting
piston can be moved to rivet contact position before full
riveting pressure is applied, thus, allowing accurate con-
tact rivet alignment prior to a rivet squeezing operation.
Another feature of the tool of the present inventionis that movement of the throttle valve to the non-operative
position during any part of the power stroke or in the stall
condition results in rapid movement of the piston in the
hydraulic cylinder away from the rivet setting position.
The tool of the present invention can be provided
either with a C type riveting yoke, or an alligator type
riveting yoke, the latter being arranged to provide the same
output force regardless of reach, such being accomplished by
a different mechanical advantage in each size. In pneumatic
type riveters using a wedge and roller arrangement in an
alligator tvpe yoke, the riveting pressure decreases as the
reach ~length) increases.
A further feature of the tool of the present invention
is a throttle lever safety arrangement whereby the throttle
-2~ Z ~
lever must be pushcd forward before it is in tool operat-ive
condition.
Still another eature is that full tool pressure can
be appl.ied at all times to the rive-t throughout the enti.re
rivet setting operati.on until power cutoff.
The present inven-tion provides a pneumatic hydraulic
tool having a cylindrical housing, a backhead affixed at
one end of the cylindrical housing, a hydraulic cylinder
affixed to the other end of the cylindrical housing, a work
engaging means secured to the hydraulic cylinder, a reservoir
element enclosed in the cylindrical housing, a flexible
bladder arranged in the reservoir element which bladder
encloses hydraulic medium and may be exposed to pressurized
pneumatic medium on the exterior thereof, a piston enclosed
in the hydraulic cylinder which piston may be hydraulically
driven toward the work engaging means, a piston driven ram
in the cylindrical housing, said backhead enclosing a throttle
valve and a cycling valve, said throttle valve being movable
from non-operative position to two operative positions the
first of which results in exposure of the bladder to pres-
surized air to force hydraulic medium from the reservoir
element to cause movement of the piston toward the work
engaging means, the second of which results in operation
of the cycling valve to direct pressurized pneumatic medium
to the cylindrical housing to cause movement of the piston
driven ram whereby pressurized hydraulic medium is directed
to the piston in the hydraulic cylinder so that a work
operation is effected.
These and further features and advantages of the
invention will become apparent from the following description
and accompanying drawings wherein:
~ ig. 1 is a longitudinal fragmented section view of a
tool embodying the principles of the invention;
Fig. 2 is a longitudinal section view of a tool like
that of Fig. 1, but showing a cross section taken at a
40~
different angle than that o~ the cross section of Flg. 1,
and with an alllgator rive-ting yoke being used instead of
the C clamp yoke of ~he tool of Fig. l;
Fig. 3 ls a cross section view of certain portions of
the tool backhead and showing -the throttle valve and air
flow control cycling valve in tool shut-off, or non-
operative position;
Fig. 4 is the same as Fig. 3 but showing said valves
in pre-fill positlon;
Fig. S is the same as Fig. 3 but showing saicl valves
in cycling position;
Fig. 6 is a cross-section view through a self
relieving pressure regulator positioned in the tool backhead;
Fig. 7 is a fragmentary plan view of a throttle lever
arrangement used in the tool of the invention;
Fig. 8 is a cross-section view as seen from line 8-8
in Fig. 7;
Fig. 9 is a schematic view of the tool of Fig. 1
showing the operative parts in tool rest, or release con-
dition;
Fig. 10 is a schematic view of the tool of Fig. 1
showing the opertive parts in tool pre-fill condition;
Fig. ~1 is a schematic view of the -tool of Fig. 1
showing the operative parts in tool power stroke condition;
Fig. 12 is a schematic view of the tool of Fig. 1
showing the operative parts of the tool at end of the power
stroke;
Fig. 13 is a schematic view of the tool of Fig. 1,
showing the operative parts of the tool during return stroke
of a pneumatic piston of the tool; and
Fig. 14 is a schematic view of the tool of Fig. 1
showing the operative parts of the tool at end of return
stroke of the pneumatic piston of the tool.
Referril~g now to the drawings, Fig. 1 identifies a
pneumatic hydraulic hand-held riveting tool incorporating the
2~
princi~les of the :invent:ion, which tool includes a rnain
cylindrical nouslng 12 having a bac~head or rear cover 14,
secured at one end, and a hydraulic cylinder 16 secured at
the opposi~e end. A work enga~ing means, such as a C type
riveting yoke 18 is removably secured to a forward portion of
the hydraul.ic cylinder 16. Rivet die sets are not illus-
trated in the yoke, since these sets can be o~ varlous size
and shape. The cylindrical housing 12 encloses a ~neumatic
portion in which a piston 20 is slidingly arranyed, and a
hydraulic portion in which is located a hydraulic reservoir
22, formed within the confines of a reservoir ele~ent 24.
The peripheral reylon of t.l-e reservoir has a bladder 26
secured at each end of the reservoir element 24. The bladder
can he made from an elastomer such as Buna type N. ~ydraulic
pressurizing means other than a bladder may be utilized as
will readily be apparent to those skilled in the art.
A helical spring 28 is compressively arranged between
the piston 20 and one end of the reservoir element 24. A
filtered opening 29 is provided for venting the cylindrical
portion enclosing the spring 28.
The reservoir element 24 encloses a bushing 44 and
tube element 60 which form an axial passageway 62 that
slidingly accommodates ram 50. The reservoir element 24 also
contains a filler plug 165 and has a scavanger port 166.
Bushing 44 has radial holes 46 which, thru holes 48,
connect chamber 62 with reservoir 22. Bushing 44 also has
radial holes 58 which connect chamber 62 to cylindrical
chamber 54. As best seen in Fig. 2, cylindr.ical cavity 54
has at least one passageway 56 interconnecting the cavity
with chamber 34.
As seen in Fig. 1, tube 60 has radial holes 64
connecting chamber 62 with groove 161. An angular hole 66
connects groove 161 with the outlet of check valve 30, while
an angular hole 68 connects groove 161 with the inlet of
check valve 32. The outlet of check valve 32 is connected
5- ~-zz~o~
to the chamber 34 by a hole 162.
The hydraulic cylinder 16 encloses a piston 36, and
has a bleeder screw 163. A helical spring 38 is compres-
sively arranged between a head 40 of piston 36 and a cir-
cular abutment 42 formed on an inner portion of the cylinder16.
The tool of Fig. 2 differs from that cf Fig. 1,
primarily because an alligator yoke 70 is utilized in place
of the C clamp yoke 18. A piston 72, which is shorter
than the piston 36 of the Fig. 1 tool, is arranged to act
against a jaw 74 pivotally affixed to a complementary jaw
76 of the alligator yoke 70. A latch, or pawl mechanism
78, is provided to limit opening movement of the yoke, one
portion of the latch being arranged for abutment with a pin
80 on the jaw 74 when limited jaw opening is desired. The
jaw 76 is pivotally secured to a hydraulic cylinder 82 which
encloses a piston 72.
Within the backhead 14 is a throttle valve 84 r a
cycling valve 86 and a self-relieving pressure regulating
valve 88 all as best seen in Figs. 3 to 6. The throttle
valve 84 has a head 90, which is urged into seating engage-
ment with a bushing 94 by a compression spring 92, the
bushing 94, having radial openings 96~ The openings are in
alignment with the ends of passageway means 98, leading to
25 the cycling valve 86 and a pre-fill passageway 100 (Fig. 1
and Fig. 9) the forward end of which connects with an
opening 102 for admission of pressurized air to the exterior
of bladder 26.
The region 104 (Fig. 3) above the upper end of bushing
30 94 leads to exhaust. A throttle valve sleeve 106, affixed
to the upper end of the throttle valve 84, is engageable by
a throttle lever 108 whereby the valve may be unseated from
the bushing 94. The throttle lever 108 is affixed to one
end of a rod 109, the other end of the rod having a throttle
35 control handle 111. The rod 109 is axially movable and spring
;~ 2
biased toward non-operative position (Fig. 7). The
operator rnust shift -the control handle 111 over an abutrnent
113 on the housing 12 before it can be rotated to provide
throttle opening condition. A swivel hose connection 110 is
S arranged for admission of pressurized ai,r into charllber 112
in which the throttle head 90 is located. Throttle valve
sleeve 106 has an exterior circumferential groove 168 and is
slidingly accommodated in bushing 169 (Figs. 3 and 4).
Bushing 169 has a hole 170 which connects with
passageway 171.
The cycling valve 8~ is slidably arranged in a bushing
114, the lower end being permanently closed, -the upper end
being closed by an end cap 116 threadably affixed to the
bushing 114. The bushing has exterior circumferential groo~es
118, 120, 122 and 172 each being connected to the interior
of the bushing by radial holes 124, 126, 128 and 173,
respectively (Figs. 3 - 5~. A radial hole 140 in the
bushing 114 leads to a passageway 142 (Fig. 9) which connects
to passageway 171. Another hole 178 connects with passageway
156 which leads to signal port 154 (Fig. 9). The cycling
valve 86 has circumferential grooves 132 and 134. Groove 132
has a passageway 136 which opens into the lower region of the
bushing 114 beneath the end of the cycling valve 86, (Fig. 5).
A compression spring 143 is arranged to urge the valve 86
toward the lower end of bushing 114.
As seen in Fig. 9, groove 118 on cycling valve bushing
114 is connected to live air from passageway 147. Groove 120
connects to passageway 158 which leads to the cylinder
housing in back of piston 20. Groove 122 opens to exhaust
160. Groove 172 is connected to passageway 177 which leads
to the cylinder housing behind piston 20.
The pressure regulating valve 88 has a circumferential
groove 174 and several passages 175 through the valve upper
head. The valve has a normal position where, under the load
of adjustable spring 148 on the lower head, the valve 88 is
-- ~7 ~
held against the closed end of bushing 183. Bushing 183 has
radial ho],es 146 leading -to passageway 147, radial holes 144
leading -to passageway 173 and ven-t holes 176 and 180 connec-
ted to exhaust.
The spring pressure adjusting screw 150 is locked
in position by a nut 152. A pressure regulating valve of
the type described is similar in structure ancl operation to
that disclosed in the patent of Wallace et al 3,351,217,
with the exception of vent hole 176.
The operation of the tool of the invention is de-
picted in the schematic drawings of Figs. 9 thru 14. Fig. 3
and Fig. 9 show the operative parts of the tool in the non-
operative condition, with the throttle valve 84 closed or
seated, and the cycling valve 86 in the down position. In
such condition the cylinder area in back o~ piston 20 is
connected to exhaust via passageway 158, into groove 120,
thru bushing holes 126, into valve groove 134, out bushing
holes 128 and into yroove 122 which is connected to -the
exhaust 160. The piston 20 is fully retracted because of
spring 28.
Figs. 4 and 10 show the operative parts of the
tool in the pre-fill condition, caused by a slight opening
of the throttle valve. A small amount of air is admitted
to passageway 98, which connects to passageways 100 and 173.
Air in passageway 173 enters pressure regulating valve 88
thru port 144, out thru port 146, into passageway 147. The
air enters groove 118 on cycling valve bushing 114, thru
port 124, into groove 132 on cycling valve 86, then flows
thru passageway 136 into the region below cycling valve 86.
The air then continues to flow thru port 140, passageway 142,
to passageway 171. One end of passayeway 171 is blocked by
piston rod 50 in passageway 52; the other end of passageway
' 171 connects with port 170 in throttle valve bushing 169
,i
~'~ (Fig. 3 and Fig. 9). The air enters the bushing thru port
~;~2~
170, into r7roove lG8, on valve sleeve 106. As shown in
Fig. 4 and Fig. lO, groove 168 connects port 170 with
e~haust chal-nher ]04. Due to the air in passa~3eway 171 ~h~s
being connected to exhaust, pressure cannot build up on
the lower end of cycling valve 86 and the tool cannot cycle,
i.e. develop rivet settiny pressure. The air in passage
100 enters the reservoir chamber thru port 102 and pressur-
izes the volume outside of bladder 26.
When the volume outside the bladder is pressurized,
oil is forced out of reservoir 22. The oil goes thru port
46 and 48 into the space ahead of ram 50 in bushing 44 and
tube 60, out port 58, into chamber 54 and thru passageway
56, into piston chamber 34, causing piston 36 to advance and
contact the work. ~dditional oil may also flow from the
15 reservoir 22, thru check valves 30 and 32, into piston chamber
34
Fig. 5 and Fig. 11 show the operative parts of the
tool during a power stroke. The throttle valve 84 is fully
depressed, which allows air flow to continue in prefill
20 passageway 100, but air flow through passageway 171 to
exhaust is blocked by throttle valve sleeve 106.
At the start of the power stroke, the piston 20 and
rod 50 are fully retracted, as shown on Fig. 10 and the
throttle valve is wide open, as shown on Fig. 11. With
25 passageway 171 blocked (Fiq. 11) and piston rod 50 entered
in packing 179 (Fig. 10), chamber 52 is sealed off so that
air flow through passageway 136 can build up pressure under
cycling valve 86. The top of cycling valve 86 is vented
thru port 178, passageway 156, port 154 to the cylinder ahead
of piston 20, which is vented thru filter 29. Thus, the
pressure build up on the bottom of cycling valve 86 over-
comes spring 143 and the valve shifts to the up position.
With valve 86 in the up position ~Fig. 11), air in groove
118 enters thru bushing holes 124 into cycling valve groove
35 132, out bushing holes 126, into groove 120, thru passageway
9 :~2;~
l58 to the cylin(ler housing in back of piston 20. Hole 173
i5 hlocked by valve ~6. The piston 20 moves forward due to
the pressure b~hind it. '['he forward end of ram 50 crosses
port 46 and then port 58 in bushing ~4, thus blockiny them
o~f. Pressure builds ahead of ram 50, forcing the hydraulic
medium tnru check valve 32, ou-t port 162, in~o chamber 34.
The ram 50 will continue to rnove forward until either
the hydraulic pressure ahead of ram 50 times the ram area
equals the air pressure behind plston 20 times the pis-ton
area causing the piston 20 to stop or 'stall'', or the piston
20 will go beyond port 154 (Fig. 12). I~ihen piston 20 passes
port 154, air pressure behind piston 20 enters port 154, goes
through passageway 156, thru port 178, and pressurizes the
top of valve 86. This equalizes the pressure on both ends of
valve 86, allowing spring 143 to return the valve to its
normal (down) position.
With valve in the down pOsitioll, the air behind piston
20 is connected to exhaust through passageway 158, groove
120, holes 126, groove 134, holes 128, into groove 122, and
out exhaust 160. When the pressure behind piston 20 goes
to exhaust, spring 28 is able to return piston 20 and ram 50.
As ram 50 returns, the hydraulic pressure ahead of it
drops and additional f~uid from reservoir 22 is forced (due
to air pressure on bladder 26) through check valve 30 into
volume ahead of ram 50. Piston 20 continues to return until
the extension of ram 50 behind piston 20 enters packing 179
(Fig. 14). This seals off chamber 52 and allows air pressure
to build up under valve 86, hereinbefore described and the
valve shifts up, causing the piston 20 to start forward
again. This cycling will continue until the tool '-stalls''
or the throttle is released.
~ s shown on Fig. 14, the shift point for valve 86
occurs when the ram 50 enters packing 179. Therefore, ram
50 never uncovers ports 58 or 46 during normal cycling and
the unit cycles until the output pressure that '-stalls-- the
--lC)-
~2~
tool is reached.
~hen the t]-~rottle control handle 111 is released,
throttle valve 84 ~-eturns to sea-ting engagement on bushiny
94, shutting off air to the tool. As seen in Fig. 3,
5 spring 182 moves valve sleeve 106 up connecting cavity 98,
thru holes 96 into bushing 94, and then to exhaust 104.
The air pressure ~Inder cycling valve 86 is exhausted, and
valve 86 shifts down exhausting all remaining air behlnd
piston 20.
The piston 20 and rarn 50 are retracted because of
spring 28 (Fig. 9). Spring 42 moves cylinder 36 back,
forcing the oil from chamber 34, through passageway 56 to
groove 54, through holes 46 into bushing 44, and out of holes
48 into reservoir 22.
The pressure regulator (Figs. 6 and 9 thru 14) contains
an adjustable spring 148, which urges valve 88 toward the
closed end of bushing 183. Spring adjusting screw 150 has
a vent hole 180 through it. Adjustment is made by loosening
nut 152 and turning screw 150, thus causes nut 181 to move
up or down the screw, changing the spring load Nut 152
is tightened to lock screw 150 in position.
Air is admitted to the necked do~n portion of valve
88 through holes 144. The valve has holes 175 through its
upper head, which cause the valve to be pneumatically
unbalanced and move toward compressing spring 148, thereby
restricting the inlet ports 144. The resulting restricted
supply flow through inlet por-t 144 reduces the pressure
inside the bushing until the pressure acting on the regulator
valve is equal to the spring force. Consequently, the
pressure of the air passing through the outlet ports 146 to
the tool will be reduced.
In the event that the pressure to the tool should
exceed the spring setting tdue to leakage into the stalled
tool), the valve would compress the spring enough to open
vent 176 and bleed off the excess pressure.
To flll the tool wlth hydraulic fluid -the filter
elemellt 29 is removed prov:iding access to plug 165 (Fig. 1).
Plug 165 and bleeder screw 163 are removed and
hydraulic fluid is added thru plug 165 into passageway 164,
which leads to reservoir 22. As shown :in Fig. 9, hydraulic
fluid in reservoir 22 enters bushing 44 through hole 48, out
thru hole 46, into the passayeway 56 to 34 behind the piston.
Air in the system is allowed to escape out bleeder port 163.
When the reservoir is full, bleeder screw 163, plug 165, and
filter element 29 are replaced.
Any hydraulic fluid that migh-t leak past ram 50 ancl
bushing 44 cannot pass packing 167 and is returned to the
reservoir thru scavanyer port 166.
