U.S. patent number 3,602,103 [Application Number 04/846,316] was granted by the patent office on 1971-08-31 for slide-latch valve for air-driven tools.
This patent grant is currently assigned to Powers Wire Products Co., Inc.. Invention is credited to Richard E. Powers.
United States Patent |
3,602,103 |
Powers |
August 31, 1971 |
SLIDE-LATCH VALVE FOR AIR-DRIVEN TOOLS
Abstract
A latch valve of the slide type is provided in the air storage
chamber of an air-operated cylinder and piston tool which requires
a percussive or striking action followed by return to a condition
prepared for subsequent and rapidly repeated action. In the
returned and prepared condition the latch valve captures a charge
of compressed air in the storage chamber while exhausting the
cylinder so as to permit the preceding return stroke. In the fired
condition the latch valve opens the storage chamber directly into
the cylinder while closing the exhaust. In one form the latch valve
includes a port that opens into a return air reservoir when in the
fired condition to charge the same. In another form the latch valve
includes a transfer tube that cooperates with said port to exhaust
the return air reservoir after each full cycle of operation.
Inventors: |
Powers; Richard E. (San Marion,
CA) |
Assignee: |
Powers Wire Products Co., Inc.
(El Monte, CA)
|
Family
ID: |
25297537 |
Appl.
No.: |
04/846,316 |
Filed: |
July 31, 1969 |
Current U.S.
Class: |
91/443;
137/625.6; 227/130; 91/461; 137/625.66 |
Current CPC
Class: |
F15B
11/06 (20130101); F15B 2211/40515 (20130101); F15B
2211/455 (20130101); Y10T 137/86582 (20150401); F15B
2211/8855 (20130101); F15B 2211/7716 (20130101); F15B
2211/46 (20130101); F15B 2211/40507 (20130101); F15B
2211/424 (20130101); Y10T 137/8663 (20150401) |
Current International
Class: |
F15B
11/00 (20060101); F15B 11/06 (20060101); F15b
011/08 (); F15b 013/042 (); B25c 001/04 () |
Field of
Search: |
;91/461,304,469,470,443
;227/130 ;137/625.25,625.66,625.6,625.68,625.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schwadron; Martin P.
Assistant Examiner: Cohen; Irwin C.
Claims
Having described my invention, I claim:
1. In combination: a single-stroke percussively operable motor
having a cylinder with an actuating piston operable therein between
a retracted position at one end of the cylinder and an actuated
position at the other end of the cylinder, having a fluid-pressure
storage chamber of capacity to percussively actuate the piston and
overlying and next adjacent to said one end of the cylinder, having
a cylinder head axially separating the interior of the cylinder
from fluid-pressure storage chamber and with at least one axially
disposed port therethrough, and having means supplying fluid under
pressure into the said chamber; a slide latch valve movable
transversely of the cylinder head and having at least one axial
port therethrough movable out of and into alignment and with said
at least one axially disposed port in the cylinder head, said
cylinder head and said valve having mating planar surfaces; and a
manually operable fluid-actuating pilot valve means connected to
and actuating the slide latch valve from a closed position whereat
the said ports are out of alignment to an open position whereat the
said ports are in alignment; whereby fluid pressure stored in said
chamber discharges axially through said ports when the slide latch
valve is in the open position and into the said cylinder to move
the piston percussively toward the said other end of the
cylinder.
2. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head is
disposed in a plane normal to the cylinder axis, and wherein the
slide latch valve moves reciprocally in said plane to align said
ports for discharge of compressed fluid axially from the storage
chamber and into the cylinder.
3. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head has a flat
sealing face exposed within the fluid-pressure storage chamber, and
wherein the slide latch valve overlies the sealing face and is held
slideably engaged thereupon by fluid pressure in said storage
chamber.
4. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head is
disposed in a plane normal to the cylinder axis and has a flat
sealing face exposed within the fluid-pressure storage chamber, and
wherein the slide latch valve overlies the sealing face and is held
thereto to slide reciprocally in said plane and engaged upon said
sealing face by fluid pressure in said storage chamber.
5. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the manually operable
fluid-actuating pilot valve means includes a reversely operable
cylinder and piston servo and a trigger valve operable to reversely
charge the cylinder of said servo with fluid pressure.
6. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the manually operable
fluid-actuating pilot valve means includes a differential cylinder
and piston with spaced interconnected large and small pistons
exposed to fluid pressure within the storage chamber, the large
piston operable in a closed cylinder bore and the small piston
operable in an exhaust bore, and a trigger valve operable to
alternately charge said closed cylinder bore with fluid pressure
and to exhaust the same.
7. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head has a flat
sealing face exposed with the fluid-pressure storage chamber,
wherein the slide latch valve overlies the sealing face and is held
slideably engaged thereupon by fluid pressure in said storage
chamber, and wherein the manually operable fluid-actuating pilot
valve means includes a reversely operable cylinder and piston servo
extending through the fluid-pressure storage chamber and on an axis
parallel to the said flat sealing face and with the piston thereof
coupled to the slide latch valve to reciprocally position the same,
and a trigger valve operable to reversely charge the cylinder of
said servo with fluid pressure.
8. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head has a flat
sealing face exposed within the fluid-pressure storage chamber,
wherein the slide latch valve overlies the sealing face and is held
slideably engaged thereupon by fluid pressure in said storage
chamber, and wherein the manually operable fluid-actuating pilot
valve means includes a trigger-operated fluid-actuated servo
extending through the fluid-pressure storage chamber and on an axis
parallel to the said flat sealing face and with a piston
telescopically coupled to the slide latch valve on an axis normal
to the plane of said flat sealing face to adjustably seat
thereon.
9. The single-stroke percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means as set forth in claim 1 wherein, the cylinder head has a flat
sealing face exposed within the fluid-pressure storage chamber,
wherein the slide latch valve overlies the sealing face and is held
slideably engaged thereupon by fluid pressure in said storage
chamber, and wherein the manually operable fluid-actuating pilot
valve means includes a trigger-operated fluid-actuated servo
extending through the fluid-pressure storage chamber and on an axis
parallel to the said flat sealing face and with a piston
telescopically coupled to and with means yieldingly pressing the
slide latch valve on an axis normal to and toward the plane of said
flat sealing face to adjustably seat thereon. 10The single-stroke
percussively operable cylinder and piston motor combined with the
slide latch valve and manually operable means as set forth in claim
1 wherein, the cylinder head has a flat sealing face exposed within
the fluid-pressure storage chamber, wherein the slide latch valve
overlies the sealing face and is held slideably engaged thereupon
by fluid pressure in said storage chamber, wherein the manually
operable fluid-actuating pilot valve means includes a differential
cylinder and piston extending through the fluid-pressure storage
chamber and on an axis parallel to said flat sealing face and with
spaced interconnected large and small pistons exposed to fluid
pressure within the storage chamber, the large piston operable in a
closed cylinder bore and the small piston operable in an exhaust
bore, wherein the slide latch valve is telescopically coupled to
the interconnected pistons on an axis normal to the plane of said
flat sealing face to adjustably seat thereon, and wherein a trigger
valve is operable to alternately charge said closed cylinder bore
with fluid pressure and to exhaust the same.
In combination: a double-acting percussively operable motor having
a cylinder with an actuating piston operable therein between a
retracted position at one end of the cylinder and an actuated
position at the other end of the cylinder, having a fluid-pressure
storage chamber of capacity to percussively actuate the piston and
axially overlying and next adjacent to said one end of the
cylinder, having a cylinder head separating the interior of the
cylinder from the fluid-pressure storage chamber and with
transversely spaced axially disposed inlet and exhaust ports
therethrough, and having means supplying fluid under pressure into
the said chamber; a slide latch valve movable transversely of the
cylinder head and having transversely spaced axially disposed inlet
and exhaust ports complementary to and alternately movable out of
and into alignment with the inlet and exhaust ports in the cylinder
head, said cylinder head and said valve having mating planar
surfaces; a manually operable fluid-actuating pilot valve means
actuating the slide latch valve from a closed position whereat the
said inlet ports are out of alignment and the said exhaust ports
are in alignment, to an open position whereat the said inlet ports
are in alignment and said exhaust ports are out of alignment;
whereby fluid pressure stored in said chamber discharges axially
through said inlet ports when the slide latch valve is in the open
position and into the said cylinder to move the piston percussively
toward the said other end of the cylinder, and whereby fluid
discharged into the cylinder is exhausted axially through said
exhaust ports when the slide latch valve is in the closed position,
and return means applying fluid pressure to beneath the
piston when the slide latch valve is in said closed position. 12.
The double-acting percussively operable cylinder and piston motor
combined with the slide latch valve and manually operable means and
return means as set forth in claim 11 wherein, there is a
multiplicity of complementary inlet ports through the cylinder head
and slide latch valve and spaced equally transversely in the
direction that the slide latch valve is moved.
3. The double-acting percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means and return means as set forth in claim 11 wherein, there is a
multiplicity of complementary and equally spaced slot-shaped inlet
ports through the cylinder head and slide latch valve and disposed
normal to the transverse
direction that the slide latch valve is moved. 14. The
double-acting percussively operable cylinder and piston motor
combined with the slide latch valve and manually operable means and
return means as set forth in claim 11 wherein, there is a
multiplicity of complementary and equally spaced slot-shaped inlet
ports through the cylinder head and slide latch valve and extending
substantially coextensive between opposite walls of the cylinder
and disposed normal to the transverse direction that the
slide latch valve is moved. 15. The double-acting percussively
operable cylinder and piston motor combined with the slide latch
valve and manually operable means and return means as set forth in
claim 11 wherein, there is a single complementary exhaust port
through the cylinder head and slide latch valve respectively and
aligned on the center axis of the cylinder
and piston when the slide latch valve is in said closed position.
16. The double-acting percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means and return means as set forth in claim 11 wherein, there is a
multiplicity of complementary inlet ports through the cylinder head
and slide latch valve and spaced equally in the transverse
direction that the slide latch is transversely movable, and wherein
there is a single complementary exhaust port through the cylinder
head and slide latch valve respectively and aligned on the center
axis of the cylinder and piston when the slide latch valve is
in
said closed position. 17. The double-acting percussively operable
cylinder and piston motor combined with the slide latch valve and
manually operable means and return means as set forth in claim 11
wherein, there is a multiplicity of complementary and equally
spaced slot-shaped inlet ports through the cylinder head and slide
latch valve and disposed normal to the transverse direction that
the slide latch valve is moved, and wherein there is a single
complementary exhaust port through the cylinder head and slide
latch valve respectively and aligned on the center axis of the
cylinder and piston when the slide latch valve is in said closed
position.
8. The double-acting percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means and return means as set forth in claim 11 wherein, there is a
multiplicity of complementary and equally spaced slot-spaced inlet
ports through the cylinder head and slide latch valve and extending
substantially coextensive between opposite walls of the cylinder
and disposed normal to the transverse direction that the slide
latch valve is moved, and wherein there is a single complementary
exhaust port through the cylinder head and slide latch valve
respectively and aligned on the center axis of the cylinder and
piston when the slide latch valve is in said closed position.
9. The double-acting percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means and return means as set forth in claim 11 wherein, the
manually operable fluid-actuating pilot valve means includes a
differential cylinder and piston with spaced interconnected large
and small pistons exposed to fluid pressure within the storage
chamber, the large piston operable in a closed cylinder bore and
the small piston operable in an exhaust bore, said exhaust port
through the slide latch valve being open through the interconnected
pistons to the said exhaust bore, and a trigger valve operable to
alternately charge said closed cylinder bore with fluid
pressure and to exhaust the same. 20. The double-acting
percussively operable cylinder and piston motor combined with the
slide latch valve and manually operable means and return means as
set forth in claim 11 wherein, the cylinder head has a flat sealing
face exposed within the fluid-pressure storage chamber, wherein the
slide latch valve overlies the sealing face and is held slideably
engaged thereupon by fluid pressure in said storage chamber,
wherein the manually operable fluid-actuating pilot valve means
includes a differential cylinder and piston extending through the
fluid-pressure storage chamber and on an axis parallel to said flat
sealing face and with spaced interconnected large and small pistons
exposed to fluid pressure within the storage chamber, the large
piston operable in a closed cylinder bore and the small piston
operable in an exhaust bore, wherein the slide latch valve is
telescopically coupled to the interconnected piston on an axis
normal to the plane of said flat sealing face to adjustably seat
thereon, said exhaust port through the slide latch valve being open
through said telescopic couple to open through said exhaust bore,
and wherein a trigger valve is operable to alternately charge said
closed cylinder bore with fluid pressure and to
exhaust the same. 21. In combination: a double-acting percussively
operable motor having a cylinder with an actuating piston operable
therein between a normally retracted position at one end of the
cylinder and an actuated position at the other end of the cylinder,
having a fluid-pressure storage chamber axially overlying and next
adjacent to said one end of the cylinder, having a return fluid
reservoir in open communication into the said other end of the
cylinder, having a cylinder head separating the interior of the
cylinder from the fluid-pressure storage chamber and with
transversely spaced axially disposed inlet and exhaust
reservoir-charging ports, and having means supplying fluid under
pressure into the said chamber; a slide latch valve movable
transversely of the cylinder head and having transversely spaced
axially disposed inlet and exhaust and reservoir charging ports
complementary to and alternately movable out of and into alignment
with the inlet and exhaust and reservoir charging ports in the
cylinder head, said cylinder head and said valve having mating
planar surfaces; a manually operable fluid-actuating pilot valve
means actuating the slide latch valve from a closed position
whereat the said inlet ports and said reservoir-charging ports are
out of alignment and the said exhaust ports are in alignment, to an
open position whereat the said inlet ports and said
reservoir-charging ports are in alignment and the said exhaust
ports are out of alignment; whereby fluid pressure stored in said
chamber discharges axially through said inlet ports and said
reservoir-charging ports when the slide latch valve is in the open
position and into the said cylinder to move the piston percussively
toward the said other end of the cylinder and into said return
fluid reservoir, and whereby fluid discharged into the cylinder is
exhausted axially through said exhaust ports when the slide latch
valve is in the closed position and the piston is returned to the
normally retracted position by fluid pressure from the return fluid
reservoir
applied into the other end of the cylinder and beneath the piston.
22. The double-acting percussively operable cylinder and piston
motor combined with the slide latch valve and manually operable
means and return-fluid reservoir as set forth in claim 21 wherein,
the cylinder head extends radially of the cylinder to overlie the
return-fluid reservoir with the reservoir-charging ports through
the said head and slide latch valve opening from the fluid-pressure
storage chamber and into the return-fluid
reservoir when the slide latch valve is in the open position. 23.
The double-acting percussively operable cylinder and piston motor
combined with the slide latch valve and manually operable means and
return-fluid reservoir as set forth in claim 21 wherein, the
cylinder head extends radially of the cylinder to overlie the
return-fluid reservoir with the reservoir-charging ports through
the said head and slide latch valve opening from the fluid-pressure
storage chamber and into the return-fluid reservoir when the slide
latch valve is in the open position, and wherein the manually
operable fluid-actuating pilot valve means includes a differential
cylinder and piston with spaced interconnected large and small
pistons exposed to fluid pressure within the storage chamber, the
large piston operable in a closed cylinder bore and the small
piston operable in an exhaust bore, and a trigger valve operable to
alternately charge said closed cylinder bore with fluid pressure
and to exhaust the
same. 24. The double-acting percussively operable cylinder and
piston motor combined with the slide latch valve and manually
operable means and return-fluid reservoir as set forth in claim 21
wherein, the cylinder head extends radially of the cylinder to
overlie the return-fluid reservoir with the reservoir-charging
ports through the said head and slide latch valve opening from the
fluid-pressure storage chamber and into the return-fluid reservoir
when the slide latch valve is in the open position, wherein the
cylinder head has a flat sealing face exposed within the
fluid-pressure storage chamber, wherein the slide latch valve
overlies the sealing face and is held slideably engaged thereupon
by fluid pressure in said storage chamber, wherein the manually
operable fluid-actuating pilot valve means includes a differential
cylinder and piston extending through the fluid-pressure storage
chamber and on an axis parallel to said flat sealing face and with
spaced interconnected large and small pistons exposed to fluid
pressure within the storage chamber, the large piston operable in a
closed cylinder bore and the small piston operable in an exhaust
bore, wherein the slide latch valve is telescopically coupled to
the interconnected pistons on an axis normal to the plane of said
flat sealing face to adjustably seat thereon, and wherein a trigger
valve is operable to alternately charge said closed cylinder bore
with fluid
pressure and to exhaust the same. 25. In combination: a double
acting percussively operable motor having a cylinder with a
self-returning actuating piston operable therein between a normal
retracted position at one end of the cylinder and an actuated
position at the other end of the cylinder, having a fluid pressure
storage chamber axially overlying and next adjacent to said one end
of the cylinder, having a return fluid reservoir in open
communication into the said other end of the cylinder, having a
cylinder head separating the interior of the cylinder from the
fluid pressure storage chamber and with transversely spaced axially
disposed inlet and exhaust and reservoir relief ports, having a
check valve admitting fluid from said one end of the cylinder and
into the return fluid reservoir, and having means supplying fluid
under pressure into the said chamber, a slide latch valve movable
transversely of the cylinder head and having transversely spaced
axially disposed inlet and exhaust and reservoir relief ports
complementary to and alternately movable out of and into alignment
with the inlet and exhaust and reservoir relief ports in the
cylinder head, said cylinder head and said valve having mating
planar surfaces; a manually operable fluid actuating pilot valve
means actuating the slide latch valve from a closed position
whereat the said inlet ports are out of alignment and the said
exhaust and reservoir relief ports are in alignment, to an open
position whereat the said inlet ports are in alignment and the said
exhaust and reservoir relief ports are in alignment, to an open
position whereat the said inlet ports are in alignment and the said
exhaust and reservoir relief ports are out of alignment; whereby
fluid pressure stored in said chamber discharges axially through
said inlet ports when the slide latch valve is in the open position
and into the said cylinder to move the piston percussively toward
the said other end of the cylinder, and through said check valve
charging said reservoir, and whereby fluid discharged into the
cylinder is exhausted axially through said exhaust ports when the
slide latch valve is in the closed position and the piston is
returned to the normally retracted position by fluid pressure from
the return fluid reservoir
applied into the other end of the cylinder and beneath the piston.
26. The double acting percussively operable cylinder and
self-returning piston motor combined with the slide latch valve and
manually operable means and return fluid reservoir as set forth in
claim 25 wherein the cylinder head extends radially of the cylinder
to overlie the return fluid reservoir with the reservoir relief
ports through the said head and slide latch valve opening from the
return fluid reservoir to an exhaust port when the
slide latch valve is in the closed position. 27. The double acting
percussively operable cylinder and self-returning piston motor
combined with the slide latch valve and manually operable means and
return fluid reservoir as set forth in claim 25 wherein the
cylinder head extends radially of the cylinder to overlie the
return fluid reservoir with the reservoir relief ports through the
said head and slide latch valve opening from the return fluid
reservoir to an exhaust port when the slide latch valve is in the
closed position, and wherein the manually operable fluid actuating
pilot valve means includes a differential cylinder and piston with
spaced interconnected large and small pistons exposed to fluid
pressure within the storage chamber, the large piston operable in a
closed cylinder bore and the small piston operable in an exhaust
bore, and a trigger valve operable in an exhaust bore, and a
trigger valve operable to alternately charge said closed cylinder
bore with fluid pressure and to
exhaust the same. 28. The double acting acting percussively
operable cylinder and self-returning piston motor combined with the
slide latch valve and manually operable means and return fluid
reservoir as set forth in claim 25 wherein the cylinder head
extends radially of the cylinder to overlie the return fluid
reservoir with the reservoir relief ports through the said head and
slide latch valve opening from the return fluid reservoir to an
exhaust port when the slide latch valve is in the closed position,
and wherein the cylinder head has a flat sealing face exposed
within the fluid pressure storage chamber, wherein the slide latch
valve overlies the sealing face and is held slideably engaged
thereupon by fluid pressure in said storage chamber, wherein the
manually operable fluid actuating pilot valve means includes a
differential cylinder and piston extending through the fluid
pressure storage chamber and on an axis parallel to said flat
sealing face and with spaced large and small pistons exposed to
fluid pressure within the storage chamber, the large piston
operable in a closed cylinder bore and the small piston operable in
an exhaust bore, wherein the last said piston operable in an
exhaust bore, wherein the last said piston is telescopically
coupled to the slide latch valve on an axis normal to the plane of
said flat sealing face to reciprocally position the same, and
wherein a trigger valve is operable to alternately charge said
closed cylinder bore with fluid pressure and to exhaust the same.
Description
The present invention relates primarily to percussive-action tools
such as fastener-driving tools which strike and/or hammer a
fastener into a piece of work by means of a single blow. Therefore,
a complete cycle of operation requires preparation of the tools for
adequate subsequent functioning, followed by said functioning, and
consummated by the function of return to a prepared condition for
completing the said cycle. Heretofore, tools of the type under
consideration have employed air storage chambers for supplying the
immediate and high demand for the instant supply of air under
pressure and such as to have an explosive action when released.
However, the valve design in the prior art tools has been such as
to restrict the flow of air into the drive cylinder; reference
being made to poppet-type valves that lift off the top end of the
cylinders, wherein there is inherently a gradual separation from
the valve seat resulting in a detainment of the percussive action
desired. Therefore, it is an object of this invention to provide
the slide-type latch valve hereinafter disclosed and which
instantaneously moves to a fully open position and directly
discharges compressed air from said chamber and into said cylinder
and without turning and/or redirecting said air. Consequently,
explosive action of the stored air under pressure is instantly
effective at the beginning of the work stroke of the tool to
accelerate the piston and in this instance the driver blade
attached thereto.
Latch valves for tools of the type under consideration are most
often servo operated by means of a trigger valve that either bleeds
or supplies air for opening the latch valve, and in either case
there is detainment in the valve action due to inertia of parts and
due to the distance of travel required in order to attain full
opening of the latch valve. In other words, instantaneously
full-opening latch valves directly communicating the air storage
reservoir and tool actuation cylinder are unavailable in the prior
art, it being an object of this invention to provide such a valve
that is operable through a trigger valve and preferably under
positive pressure application that ensures a quick instantaneously
opening to a full communication condition.
Percussive-type tools of the type under consideration include air
return means that are charged during the work stroke of the tool
and which operate independently of the drive function to return the
piston and driver blade to a prepared condition for the next work
cycle. In a sense these cylinder and piston motors are
double-acting, but characterized by operating upon the drive air
pressure after the end of the work stroke is reached by the piston
and to thereafter return the same. Such tools have return air
reservoirs that accumulate a portion of the drive air and ported
into the cylinder beneath the piston to lift it when the upper end
of the cylinder is exhausted, it being a general object of this
invention to provide a latch valve that positively charges the
return air reservoir in timed relation to release of the drive air
from the storage chamber.
In practice, the inclusion of air return means operating upon
accumulated drive air pressure, as generally stated in the
preceding paragraph, has had its drawbacks in that a buildup of air
pressure in the return air reservoir is openly ported to act
beneath the piston and consequently imposes a retarding effect
which prevents rapid firing of the tool. Therefore, it is an object
of this invention to provide a return air bleed that is operative
at the end of each complete work cycle to virtually eliminate the
accumulation and/or buildup of air under pressure beneath the
piston at the end of its return stroke. And it is also an object of
this invention to provide a return air bleed that is operative with
self-return pistons or other means which include the valving that
charges the return air reservoir.
It is also an object of this invention to provide a novel assembly
of elements meeting all of the requirements hereinabove referred to
and which involves but few simple and easily formed parts. The
latch valve per se is a self-sealing element which is carried
between two extreme positions to have a self-lapping and automatic
wear takeup action. There is the usual trigger valve that operates
a novel differential piston that servos the latch valve to move it
instantly to the two extreme positions required. Assembly is
facilitated by the use of snaprings, O-rings and with the entire
latch valve mechanism accommodated in the air pressure chamber that
is established by installing a single head or cover. The said cover
has a diametrically disposed differential bore therethrough that
operatively carries the servo piston rod, and to which the latch
valve per se is keyed in position rotatably and generally as to
height. The cylinder head is in the form of a ported disc that
closes both the main drive cylinder and the air return reservoir,
and all of which is captured in working position mainly through
installation of the single head or cover on the body. It is,
therefore, an object of this invention to provide a novel and most
utilitarian combination of parts and elements cooperatively
arranged as thus far described.
The various objects and features of this invention will be fully
understood from the following detailed description of the typical
preferred forms and applications thereof, throughout which
description reference is made to the accompanying drawings, in
which:
FIG. 1 is a cross-sectional elevation taken through a typical
cylinder and piston operated tool incorporating therein the slide
latch valve of the present invention. FIGS. 2 and 3 are enlarged
detailed sectional views taken as indicated by lines 2--2 and 3--3
on FIG. 1. FIG. 4 is an enlarged detailed sectional view of a
portion of the tool and taken as indicated by line 4--4 on FIG. 2,
showing the closed positioning of the slide latch valve. FIG. 5 is
a view similar to FIG. 4, showing the open positioning of the slide
latch valve.
FIG. 6 is a view similar to FIG. 4 illustrating a second embodiment
of the present invention, showing the closed positioning of the
slide latch valve. FIG. 7 is a view similar to FIG. 6 showing the
open positioning of the valve to both drive the piston and to
charge the return air reservoir. FIG. 8 is a detailed fragmentary
view of the slide latch valve features shown in FIGS. 6 and 7,
being taken as indicated by line 8--8 on FIG. 6.
FIG. 9 is a view similar to FIGS. 4 and 6 illustrating a third
embodiment of the present invention, showing a closed positioning
of the slide latch valve to exhaust both the cylinder and the
return air reservoir. FIG. 10 is a view similar to FIG. 9 showing
the open positioning of the valve to both drive the piston and to
charge the return air reservoir. FIGS. 11 and 12 are detailed views
taken as indicated by lines 11--11 and 12--12 on FIGS. 9 and 10
respectively.
The air drive tools with which the present invention is concerned
are for fastener driving and involve, generally, a frame A having a
body portion and a handle or grip portion, a fastener guideway
block B carried by the frame and adapted to direct fasteners into a
piece of work, a magazine C for handling a supply of fasteners such
as staples and cooperating with the guideway block B so that the
fasteners are individually delivered into the work, a cylinder E
and piston F operating a driver blade D, said cylinder E having a
head G and all of which is arranged to establish a return air
reservoir R surrounding the cylinder and an air storage chamber H
overlying the cylinder and said reservoir, and in accordance with
the invention a slide latch valve V cooperatively overlying the
cylinder head G and a servo means S that moves and orients the
latch valve for cooperation with porting in the head G. And in
carrying out the invention there are various and other unique
features all as hereinafter described.
The frame A carries the various elements of the tool, and is shaped
to be conveniently handled by a person. The body portion of the
frame is a simple elongate case 10 having a cylindrical wall
extending longitudinally thereof and having an opening and recess
at the lower end for receiving and positioning the guideway block
B. The handle or grip portion 11 of the frame is provided to give
the person handling the tool a convenient means to hold the tool
and is a simple grip of ordinary construction that projects from
the body. In practice, the grip is substantially normal to the axis
of the body and projects therefrom. In structures of the type under
consideration the body and grip portions of the frame are hollow
and establish an air storage chamber H, and it is common practice
to provide a continuously open fluid-pressure supply connection 12
at the grip. It is to be understood that any suitable
fluid-pressure supply can be provided and in the case illustrated
the hose of the pressure connection is attached to the grip through
a quick disconnect.
The guideway block B extends through the lower end of the frame A
and is provided to receive and deliver fasteners such as staples
into the work being acted upon by the tool. The guideway block B is
carried by the body in the recess provided therefor and has a
limited leakage guideway therethrough that opens at its top into
the cylinder and at its bottom to atmosphere or against the work.
The driver blade D is slender elongate, part rectangular in cross
section, and corresponding to the cross section of the guideway in
block B to slide freely therein with said limit leakage of air
thereby. The driver blade terminates at its forward end at a flat
driving face and has an upper driven portion which couples with and
has driving engagement with the piston E.
The magazine C is adapted to handle a supply or stack of fasteners
such as U-shaped staples and involves a case 15 carried by the
frame A, a guide 16 within the case, a follower 17 adapted to
advance the staples, and a feed spring 18 yieldingly urging the
follower toward the guideway and block B. A fastener or
staple-receiving opening 14 extends laterally through the guideway
block B, which opening enters through and into the guideway therein
so that the fasteners fed to the guideway are properly guided and
aligned before they are engaged by the driver blade D. The case 15
is carried by the body of the frame A and is an elongate shell-like
part, and the guide 16 is a corelike part that is coextensive with
the case 15 and is carried between the sidewalls thereof. A
longitudinal passage 19 is formed by the case 15 conforming in
general configuration to the fasteners being deployed, for example
the U-shaped staples. The guide 16 enters the fastener or
staple-receiving opening 14 and terminates in a flat end short of
the drive blade D, and in the usual manner whereby one fastener is
removed from the magazine upon each drive stroke of the tool.
The piston F operates in the cylinder E and has coupled driving
engagement with the driver blade D. The piston F is adapted to
drive or move the driver blade D forwardly or downwardly and is
adapted to be damped or snubbed in momentary sealed engagement with
a bumper 20 at the lower end of the cylinder E and after which it
is returned to the upper end of the cylinder. The cylinder is
carried in the surrounding cylindrical body of the frame A on the
longitudinal axis thereof, being seated in the body at the lower
end thereof to stand free in the body with its upper end opening
into the chamber H through the cylinder head G, and leaving an
annulus within the cylindrical body establishing the return air
reservoir R. The piston F moves the length of the cylinder E,
arresting against the cylinder head G and rebounding from the
bumper 20, said bumper being formed of an elastomer material with a
parallel opening therethrough to pass the driver blade D. In
carrying out the invention and in order to effect return of the
piston F to an arrested and prepared condition at the upper end of
the cylinder E, there are ports 21 opening through the wall of the
cylinder E at the lowermost end thereof and immediately above the
bumper 20. Thus, the return air reservoir R is in continued open
communication with the interior of cylinder E and always below the
piston F.
The slide valve of the present invention is cooperatively combined
into the tool hereinabove described, as follows: the cylinder head
G is installed upon the top end of cylinder E and in sealed
engagement with the cylindrical body of frame A. The servo means S
is installed in the cover 25, and the trigger valve T is installed
in either the cover 25 or the body 10 and preferably in the latter.
The latch valve V is then installed upon the servo means S
previously installed and carried thereby into working position and
slideably engaged with the cylinder head G when the cover 25 is
brought into mating and closed engagement with the body 10. The
final mating of cover 25 with body 10 also places the valving
elements of trigger valve T in working position in a valve chamber
preferably in the cover 25. Suitable means such as screw fasteners
24 secure the cover 25 to the body 10, preferably at a parting line
parallel to and spaced above the cylinder head G, and consequently
said head is carried in a bore 26 and rests upon a shoulder 27
where it is sealed by an O-ring.
The cylinder head G is a flat disc-shaped part of substantial
thickness and strength as shown, preferably made of metal with a
flat and smooth upwardly exposed sealing face 28 in a plane normal
to the cylinder axis. The downwardly disposed face 29 of the head
closes the cylinder E and the reservoir R, there being an O-ring 30
carried in a annular groove that receives the upper terminal end of
cylinder E. Thus and in accordance with the invention the cylinder
head G presents the upwardly disposed sealing face 28 that is
ported at 31 so as to open axially from chamber H into the interior
of cylinder E. In order to gain a maximum port area with minimized
valve travel, there is a multiplicity of ports 31 equally spaced in
the direction of valve travel, and as shown each port 31 is a slot
disposed transversely of valve travel or movement and extending
between the inner diameter walls of the cylinder E. The
multiplicity of slotted ports 31 are each less in width than the
distance therebetween, so as to establish a substantial overlap
with the latch valve V next to be described. And in practice, the
slot-shaped ports 31 are suitably interrupted by interconnecting
webs 32 that reinforce the head G, while the ends and/or sides of
the slotted ports next adjacent the inner diameter walls of the
cylinder are contoured to the curvature of said cylinder wall,
coextensively with the area of the cylinder as shown. Thus, a
substantial and maximum cross-sectional area of porting is
attained. Further and in accordance with the invention certain
areas of the cylinder head G are reserved for exhausting the
cylinder E, for charging the reservoir R and for exhausting
reservoir R all as hereinafter described, the porting 31 serving to
instantaneously charge the cylinder E.
In accordance with the invention, the latch valve V is provided and
cooperatively engages upon the sealing face 28 to move into and out
of register with the port or ports 31. Therefore, the latch valve V
is provided with one or more ports 33 complementary to the ports 31
and arranged in a like pattern, so that the ports of the latch
valve V align with the ports of the head G for open communication,
or so that they move out of register thereby to close off the
cylinder E from the chamber H. The latch valve V is also a flat
part overlying the cylinder E, and preferably more than
coextensively overlying the same, and preferably made of
polypropelene or the like and which has a coefficient of friction
with metal such as aluminum to slide freely thereon, with or
without lubrication. The body of the latch valve V is essentially a
flat platelike rectangular solid as shown in FIGS. 1 and 2, and it
is provided with a reserved area overlying a complementary area of
the head G. In practice, these said reserved areas are for
exhausting the cylinder E and are advantageously located on the
central axis of the cylinder and in open communication when the
latch valve is closed to shut off the ports 31. Since the return
stroke of the tool need not be percussive, the exhaust porting is
minimized and relegated to a single relatively small port 34
through the head G and a like port 35 through an upstanding boss 36
projecting from the latch valve body. From the foregoing it will be
seen that a full open position of the latch valve V is attained by
moving the same one-half the oncenter distance between slotted
ports 31 (or 33), the ports 34 and 35 being offset in position said
one-half distance for exhaust alignment and which is the starting
point of said movement for opening the latch valve V. Thus the
latch valve V has two reciprocally opposite positions, a normal
position (see FIG. 4) where the exhaust ports 34 and 35 are
aligned, and an operated position (see FIG. 5) where the charge
ports 31 and 33 are aligned.
The servo means S moves and orients the latch valve V and is
characterized by its ability to instantly reciprocate the valve
from its normal closed-exhaust positioning to its operated
cylinder-charging positioning. As shown, the servo means S is
primarily a double-acting fluid-operated cylinder and piston means
that includes a manually operable trigger valve T. In its preferred
form the means S involves a differential cylinder and piston 45
incorporated in the cover 25, with a crosshead 46 carrying the
latch valve V, and the trigger valve T incorporated in the combined
and mated body 10 and cover 25. With the chamber H continuously
charged with air under pressure the differential cylinder and
piston normally holds the latch valve V in its closed-exhaust
positioning, and alternately is operable through the application of
positively applied air pressure to instantly shift the latch valve
V into its fully open cylinder-charging position. Said positively
applied air pressure is supplied to and exhausted from the
operating cylinder of the servo means S by the trigger valve T
which is essentially a three-way valve having two positions, one a
normal position exhausting air to atmosphere from the servo
cylinder, and the other a manually operated position directing air
under pressure from chamber H and into the servo cylinder.
The cylinder and piston 45 of the servo means S is disposed on an
axis extending transversely of the cover 25 and intersecting the
axis of the cylinder E. The cover 25 is a shell-like hat-shaped
part that establishes a chamber H of substantial volume overlying
cylinder head G, and the differential cylinder portions 41 and 42
are bored concentrically in the diametrically opposite sidewalls of
the cover, and preferably through the sidewalls. The smaller
cylinder portion 41 and larger cylinder portion 42 reciprocally
carry fitted opposite ends of the piston 45, there being a stop
plug 47 arresting the piston in the normal unactuated position
(exhausting cylinder E) and there being a stop shoulder 48
arresting the piston in its operated or actuated position (charging
cylinder E). The piston 45 has an enlarged head 49 with an O-ring
seal 50 operable to move reciprocally in the larger cylinder
portion 42, and the stop plug 47 is secured in place with a
snapring 43 and has a static O-ring seal 44 engageable in the
cylinder. The cylinder portion 42 is ported between the movable
piston head 49 and plug 47 by a channel 51 that supplied and
exhausts air from and/or to the trigger valve T. The piston 45 is
of reduced diameter at X and extends through the smaller cylinder
portion 41 and an O-ring seal 53.
In accordance with the invention, and in order to discharge exhaust
air and to orient the latch valve V, the boss 36 of the valve and
the cross head 46 of the piston are coupled. A feature is the
self-sealing of the latch valve V whereby the platelike valve is
urged into pressured engagement with the face 28 by the fluid under
pressure within the chamber H. In order to permit said pressured
engagement, the coupled engagement of piston and boss permits
shifting of the valve longitudinally and axially of the tool. In
practice, the crosshead 46 and boss 36 are telescopically related,
there being a bore 54 in the crosshead on a axis normal to the
servo piston axis, the boss 36 being cylindrical to slideably enter
the bore. An O-ring 55 seals the boss within the bore, and an
exhaust channel 56 continues from the bore 54 and through the
reduced portion of piston 45 opening to atmosphere at the exterior
of the cover 25.
The trigger valve T in its normal position exhausts air from the
channel 51, and in its operated position directs air under pressure
into the channel 51. As shown the valve T involves a valve element
60 operable between upper and lower seats in a valve chamber 61, a
stem 62 exposed to be depressed by a manually controllable lever
63, and a return means 64. The stem 62 is carried in a bore
entering into and through the chamber H, being sealed with an
O-ring and with clearance surrounding the stem at the parting line
between the body 10 and cover 25. The valve element 60 is larger in
diameter than the stem 62 and has clearance within the chamber 61.
The valve elements per se are O-rings 65 and 66 at the upper and
lower ends of the valve element 60 and which seat at opposite ends
of the chamber as shown. The return means 64 is a compression
spring that normally holds the O-ring 66 against the lowermost seat
closing off the supply of air and opening the channel 51 and
chamber 61 to atmosphere through an exhaust port 67 through the
cover from the upper seat of the valve. Upon manual operation of
the valve T the O-ring 65 engages the uppermost seat closing off
the exhaust and opening the channel 51 and chamber 61 to the air
under pressure within chamber H. Thus, the trigger valve T affords
a positive pressure actuation of the servo piston 45, which then
acts to instantly shift the latch valve V to a position where it
directly charges the cylinder E. It is to be observed that the air
flow from chamber H and into cylinder E through the ports 31 and 33
is axially direct and virtually without any change in direction of
airflow.
In FIGS. 1-5 I have shown the tool and slide latch valve V as it is
hereinabove described and wherein the valve boss 36 is free to
shift telescopically within the crosshead 46, the air pressure in
chamber H serving as the sole bias to hold the latch valve V
against the cylinder head face 28. As the latch valve V is
reciprocated by the servo means S there is an inherent wearing-in
action and automatic takeup therefor, said telescoped coupled
engagement of the boss 36 and the crosshead 46 permitting axial
movement of the valve V for this purpose while maintaining vertical
alignment of the valve and crosshead. As shown, means is provided
in the form of a guide channel 80 (see FIG. 2) in the cylinder head
G, to rotatably orient the latch valve V during its reciprocal
movements. In this form of tool the piston F is self-returning,
having a check valve 70 and passage therethrough that passes air
under pressure during the work stroke to emanate beneath the piston
thereby charging the return air reservoir R through the cylinder
ports 21. When the latch valve V is closed and port 35 thereof open
to atmosphere, the stored air in reservoir R lifts the piston F to
an arrested position beneath the cylinder head G.
In FIGS. 6-8 of the drawings I have shown a second embodiment
wherein the cylinder head G.sup.1 and slide latch valve V.sup.1
include one or more ports 81 and 83 overlying the return air
reservoir R. The opening and closing of ports 81 and 83 coincide
with the opening and closing of ports 31 and 33 respectively,
thereby being normally closed and charging the return air reservoir
R only during the work stroke of the tool, and all independently of
a self-returning piston as described above.
In FIGS. 9-12 of the drawings I have shown a third embodiment of
the tool incorporating the slide latch valve V.sup.2 with an
improved crosshead 46' that retains and guides the latch valve
V.sup.2 and which includes bias means 75 initially urging the latch
valve into engagement with the face 28' of the cylinder head
G.sup.2. The rotational positioning and longitudinal retainment of
the latch valve V.sup.2 is attained by means of a key 76 having
parallel legs entering the bore in the boss through like-spaced
horizontal openings and engaged with complementary spaced flats in
the boss 36'. The bias means 75 is a compression spring that seats
upon the crosshead 46' of piston 45' and that presses against the
latch valve V.sup.2 to urge it downwardly into pressured engagement
with the cylinder head face 28'.
In the third embodiment of the tool a self-return piston is
employed, the same as hereinabove described, and positive means is
provided to exhaust the return air reservoir R at the end of each
return cycle of the tool. In this form of the invention the latch
valve V.sup.2 includes a charge port 92 and a relief port 93 that
move alternately into and out of register with charging and exhaust
port 91 through the head G.sup.2 and communicating with the return
air reservoir R. The opening and closing of charging and exhaust
port 91 coincides with the opening and closing of port 31 (or ports
31), thereby charging and exhausting the return air reservoir R
during the closed and exhaust positioning of the piston 45' and for
the duration of time that the piston F is arrested at the upper end
of the cylinder E. The charging port 92 is of ample cross section
so as to readily supply air into the return air reservoir R, while
the relief port 93 is of restricted cross section so as to act as a
beam and thereby prevent depletion of air pressure until after
completion of the return stroke of the piston F. The two positions
of the valve and said porting are shown in FIGS. 9 and 10. Note
that the cylinder head G.sup.2 has a raised face 28' for increasing
the stroke of the piston F while maintaining and/or increasing the
volume of the chamber H through open communication into grip 11. As
shown, the piston 45.degree. can be sectional with spool-shaped
piston heads operable in the cylinder portions 41 and 42.
From the foregoing it will be seen that the slide latch valve moves
transversely at a right angle to the axis of the tool and its
cylinder and piston motor. Characteristically, the charging of the
motor cylinder is performed with compressed air that moves axially
from the air storage chamber and directly into the motor cylinder.
The latch valve is guided to reciprocate across the top face of the
cylinder head which is exposed to the air storage chamber, and the
porting arrangement in the latch valve and complementary porting in
the cylinder head is such as to require but a short travel between
fully closed and fully open positionings. The latch valve per se is
a lightweight part of material that conforms to the seat upon which
it is also free to slide; and also the servo means, a
differentially operated cylinder and piston motor, is a lightweight
composite of but few simply formed parts coupled with and to shift
the latch valve. As a result of the substantial and positive air
pressure available to operate the tool, the servo means is a
rapid-operating device, whereby the moving of the latch valve,
particularly into an open position, is a quick and positive
operation and to the end that the supply of compressed air into the
motor cylinder is instantaneous when the trigger of the tool is
manually depressed. Further, the various embodiments hereinabove
described show the versatility of this slide latch such as to be
adapted to various useful arrangements effective to drive and
return the piston requiring rapid and unimpeded cycles of
operation.
Having described only typical preferred forms and applications of
my invention, I do not wish to be limited or restricted to the
specific details herein set forth, but wish to reserve to myself
any modifications or variations that may appear to those skilled in
the art.
* * * * *