Stock feed apparatus

A fluid operated stock feed apparatus for intermittently advancing stock along a feed path. The feed apparatus includes a stationary body having fluid operated stock holding clamps mounted thereon. A stock feed head is mounted for reciprocation relative to the body and has fluid operated stock feed clamps mounted thereon and a feed piston is mounted in the body for extending and retracting the stock feed head. A main control valve is provided in the body for controlling the application of fluid pressure to the fluid pressure operated stock holding and stock feed clamps and a pressure operated auxiliary valve is provided in the body and is responsive to the pressure from the main control valve for controlling the application of fluid pressure to the feed piston. The main body is formed with a bore therethrough and the feed cylinder is provided in one portion of the bore. The pressure operated auxiliary valve including an auxiliary valve casing, an auxiliary valve member and a pressure operator therefor, is mounted another portion of the bore at one end of the feed cylinder. The feed cylinder is formed by a sleeve disposed in the bore and arranged to provide a pressure chamber around the sleeve.

BACKGROUND OF THE INVENTION 
This invention relates to fluid operated stock feed apparatus for 
intermittently advancing strip stock along a feed path and particularly to 
improvements in fluid operated stock feed apparatus of the type disclosed 
in the applicant's prior U.S. Pat. No. 3,038,645. The stock feed apparatus 
disclosed in that patent in general included a stationary body, a f-uid 
operated stock holding clamp mounted on the body, a feed head mounted for 
reciprocation relative to the body and having a fluid operated stock feed 
clamp mounted thereon, and a fluid operated feed piston slidably mounted 
in a feed cylinder bore in the stationary body for extending and 
retracting the feed head relative to the stock holding clamp. A main 
control valve was mounted on the body for controlling application of fluid 
pressure to the fluid operated stock holding clamp and stock feed clamp, 
and an auxiliary valve was mounted in a stepped valve bore in the body and 
operated by fluid pressure from the main control valve to control the 
application of fluid pressure to the feed piston to extend and retract the 
feed head in timed relation with the operation of the stock holding and 
stock feed clamps. 
While the prior stock feed apparatus operated satisfactorily, it was 
somewhat expensive to machine and assemble. It was necessary to machine a 
feed cylinder bore and a separate stepped valve bore in the body, and to 
machine numerous holes or passages in the body to interconnect the main 
valve and the auxiliary valve and the fluid operated stock feed and 
holding clamps and the fluid operated feed piston and some of these 
passages were at angles that were not orthogonal to the axis of the feed 
cylinder. The feed piston was slidably mounted directly in the feed 
cylinder bore and it was accordingly necessary to machine the feed 
cylinder bore to a smooth finish. 
SUMMARY OF THE INVENTION 
An important object of the present invention is to provide an improved 
fluid operated stock feed apparatus of the type described which can be 
more economically machined and assembled. 
Accordingly, the present invention provides a fluid operated stock feed 
apparatus including a stationary body having a fluid operated stock 
holding clamp mounted thereon, a feed head mounted for reciprocation 
relative to the body and having a fluid operated stock feed clamp mounted 
thereon, a fluid operated piston slidably mounted in a feed cylinder means 
in the stationary body for extending and retracting the feed head relative 
to the stock holding clamp, a main control valve mounted on the body for 
controlling application of fluid pressure to the fluid operated stock 
holding clamp and stock feed clamp, and an auxiliary valve operated by 
fluid pressure from the main control valve and arranged to control the 
application of fluid pressure to the feed piston to extend and retract the 
feed head in timed relation with the operation of the stock holding and 
stock feed clamps, and in which the feed piston is slidably mounted in one 
portion of a bore in the body and the auxiliary valve including an 
auxiliary valve casing, auxiliary valve member and fluid pressure operator 
therefor are removably mounted in a second portion of the bore coaxial 
with the feed piston, to control the application of fluid pressure to the 
feed piston. 
In accordance with another aspect of this invention a fluid operated stock 
feed apparatus of the type set forth above, is provided with an improved 
feed cylinder means which sleeve is removably mounted in the bore in the 
stationary body to provide a cylinder inside the sleeve for the feed 
piston and a pressure chamber between the sleeve and the bore for 
transmitting fluid pressure to the rod end of the feed piston.

The stock feed apparatus of the present invention is adapted for 
intermittently feeding strip stock to a punch press or the like in timed 
relation with the operation of the press. As disclosed more fully in the 
aforementioned U.S. Pat. No. 3,038,645, the stock feed apparatus is 
arranged to be mounted on a punch press or the like, as by attachment to 
the bolster plate of the press to feed stock to the press, and the main 
control valve is operated as by a valve actuator carried by the press ram 
to cycle the stock feed apparatus in timed relation with the reciprocation 
of the ram. 
In general, the stock feed apparatus includes a stationary body 10 and a 
stock holding clamp 11 mounted on the body and actuated from a stock 
release to a stock engaging position by a fluid pressure actuator 12. A 
stock feed head 13 is mounted for reciprocation relative to the body in a 
direction paralleling the path of stock advance and a stock feed clamp 14 
is mounted on the feed head and operated from a stock release to a stock 
engaging position by fluid pressure actuators 15. A feed cylinder means 16 
is provided in the body and a feed piston 17 is slidable in the feed 
cylinder means and has its piston rod connected to the feed head for 
extending and retracting the same. A pressure operated auxiliary control 
valve 18 is provided for controlling the application of fluid pressure to 
the feed piston, and a main control valve 19 is provided in the body for 
controlling the application of fluid pressure to the fluid actuators for 
the stock holding and stock feed clamps and for also controlling the 
application of fluid pressure to the auxiliary valve. 
The stationary body 10 is conveniently in the form of a generally 
rectangular block having upper and lower side faces 10a, 10b, side edges 
10c and 10d and end faces 10e and 10f. A pair of generally parallel guide 
rods 22 are mounted on the body 10 and extend from one end 10e, and the 
feed head 13 is slidably supported on the guide rods as by bushings 23. A 
crosshead 24 extends between the outer ends of the guide rods 22 and an 
adjustable stop 25 is mounted on the crosshead as by threaded engagement 
therewith to limit the stroke of the feed head. As best shown in FIGS. 1 
and 4, the stop 25 has a nose 25a arranged to engage a part on the feed 
head 13, and the stop is adjustable in the crosshead 24 and is adapted to 
be locked in adjusted position by a lock nut 25b. Strip guides 26 are 
provided on the crosshead 24 to laterally guide the strip stock and the 
strip guides are advantageously mounted as in a T-shaped slot 24a in the 
crosshead for adjustment in a direction crosswise of the feed path, to 
accommodate stock of different width. 
The stock feed piston 17 has a piston rod 17a extending from one side of 
the piston and out of the feed cylinder and into a counterbore 13a in the 
feed head (see FIG. 4), and a bolt 31 extends through an opening 13b in 
the feed head and is threaded into the end of the piston rod 17a to secure 
the feed head to the piston rod for movement therewith. As best shown in 
FIG. 3, the stock feed clamp 14 is yieldably biased to a stock release 
position by springs 32. The fluid actuators 15 for the stock feed clamp 
comprise a pair of pistons 15a slidably mounted in cylinders 34 formed in 
the underside of the feed head 13 and the pistons 15 have piston rods 15a 
extending upwardly through bores 35 in the feed head. The stock feed 
member 14 is attached to reduced diameter extensions 15c on the upper ends 
of the piston rods 15b, as by nuts 15d. A means such as O-rings are 
provided to form a sliding seal between the periphery of the pistons 15 a 
and the cylinders 34 and also between the piston rods 15b and the bore 35 
to seal the fluid pressure chamber 34a at the upper or rod side of the 
piston. As best shown in FIGS. 3 and 4, the rod 17a of the feed piston 17 
is formed with an axial passage 17b and lateral passages 17c that 
communicate one end of the axial passage 17b with a pressure distribution 
groove 13c in the counterbore 13a, and passages 13d and 13e are formed in 
the feed head to communicate the pressure distribution groove 13c with the 
chambers 34a of the cylinders 34. The passages 13d and 13e can 
conveniently be formed by drilling a hole from one end of the feed head 13 
at a location to extend across and intersect the upper sides of the feed 
cylinders 34 and also intersect the pressure distribution groove 13c. The 
end of the hole is thereafter closed with a plug 13f. 
As best shown in FIGS. 2 and 6, the fluid operator 12 for the stock holding 
clamp 11 comprises a pair of cylinders 36 formed in the body 10 at 
opposite sides of the feed cylinder means 16, the cylinders being closed 
at their lower ends and having an annular sealing gland 37 removably 
retained in the cylinders intermediate their ends as by a split retainer 
ring 38. The fluid operator 12 also includes clamp pistons 12a slidably 
disposed in the lower portion of the cylinder 36 and rods 12b that 
slidably extend through the respective sealing gland 37. The rods 12b have 
reduced diameter upper ends 12c secured to the stock holding clamp 11 as 
by nuts 36, with the clamp extending between the pair of clamp pistons and 
crosswise of the stock feed path. A means such as O-rings are provided to 
form a seal between the cylinder 36 and the sealing gland 37 and also to 
form a sliding seal between the periphery of the clamp piston 12a in the 
cylinder and between the rod 12b and the sealing gland. The fluid 
operators 12 for the stock holding clamp are preferably of the double 
acting type with a first fluid pressure chamber 36a formed in the 
cylinders 36 at the underside of the pistons 12a and a second fluid 
pressure chamber 36b formed in the cylinder at the upper or rod side of 
the pistons. Each piston 12a is advantageously formed with a shoulder 12d 
spaced above its upper side and arranged to engage the sealing gland 37 
and to limit upward travel of the piston as shown in FIG. 2. 
The main control valve 19 is arranged to control the application of fluid 
pressure to the fluid actuators 12 for the stock holding clamp and the 
fluid actuators 15 for the stock feed clamps. As best shown in FIGS. 2 and 
6, a main valve cylinder 41 is formed in the body 10 and is closed at its 
lower end and opens at the upper side of the body. An annular main valve 
casing member 42 is positioned in the lower end of the cylinder 41 and an 
annular sealing gland 43 is provided in the upper portion of the cylinder 
and is retained therein by a split ring 44. The valve casing member 42 
defines an internal valve chamber having an inlet port 42a at its lower 
end and an exhaust port 42b at its upper end. The valve member has an 
external annular recess 42c that defines a main control port and upper and 
lower passage means 42d and 42e that communicate the valve chamber with 
the main control port at axially spaced locations. A cylindrical main 
valve member 44 is slidably mounted in the valve chamber in the valve 
casing member 42 and is movable from a first position shown in FIG. 2 
communicating the pressure inlet port 42a with passage 42e and control 
port 42c while blocking the exhaust port 42b, to a second position 
communicating the exhaust port 42b with passage 42d and control port 42c 
while blocking pressure inlet port 42a. 
Pressure supply passage means 45 are formed in the stationary body 10 and 
adapted for connection to a source of gaseous fluid pressure such as a 
source of compressed air, and an exhaust passage means 46 is adapted for 
communication to a low pressure area, for example to the surrounding 
atmosphere. A muffler 47, conveniently in the form of a perforated or 
foraminous screen, is advantageously provided in the outlet of exhaust 
passage means to reduce noise of the exhaust air. 
The stationary body 10 is formed with a cylindrical bore 51 that extends 
parallel to the stock feed path from one end 10e to the other end 10f of 
the body. A tube 56 is slidably disposed in the passage 17b that extends 
through the piston and piston rod and the tube is anchored at its other 
end to the stationary body 10. As best shown in FIG. 4, an annular head 57 
is removably mounted in one end portion of the cylindrical bore 51 and 
sealed thereto as by an O-ring to close one end of the bore 51, and the 
head is removably retained in position as by a split ring 58. A disc 
member 59 is removably disposed in the bore and has a central opening 59a 
to receive and center one end of the tube 56 in the bore 51, and a means 
such as a transverse pin 61 extends through the end of the tube and is 
retained between the disc member 59 and the head member 57 to hold the 
tube 56 against endwise movement. The head member 51 and disc 59 define a 
control pressure chamber 56a therebetween in one end of the cylindrical 
bore 51 and the control pressure chamber communicates with one end of the 
tube 56 and through tube 56 and passage 17b in the piston rod with the 
cylinder chambers 34a in the feed head. The control pressure chamber 56a 
also communicates through passages 56b with a pressure distribution groove 
recess 62 around one end of cylindrical bore 51 in the stationary body. 
A main control passage means is provided in the body to communicate the 
main control port 42c of the main control valve with the fluid pressure 
chambers 36b of the clamp cylinders and also with the control pressure 
chamber 56a to supply fluid through tube 56 and passage 56b in the piston 
to the fluid pressure chambers 34a in the feed cylinders. The main control 
passage means includes a passage 63 that communicates the control outlet 
port 42c of the main control valve member with the recess 62 and hence 
with the control pressure chamber 56a. Main control passage 63 can 
conveniently be formed by drilling a hole into one end lOof the stationary 
body at a location to intersect both the recess 62 and the main control 
port 42c and the bore can be extended as indicated at 63a to also 
communicate the control port 42c with the fluid pressure chamber 36a of 
one of the fluid pressure actuators 12 for the stock holding clamp. The 
end of the drilled hole provided to form the main control passage is 
closed as by a plug 63b after drilling. The main control passage means in 
the body 10 also includes a hole 64 drilled into the body from the end 10f 
at a location to intersect the pressure distribution groove 62 and to 
communicate at its other end with the pressure chamber 36a for the other 
fluid pressure actuator for the stock holding clamp. The end of the hole 
64 is closed as by a plug 65 after drilling. 
The auxiliary valve 18 for controlling the application of fluid pressure to 
the feed cylinder includes annular stationary valve casing means formed by 
annular valve casing members 71 and 72 removably disposed in the bore 51 
and sealed thereto as by O-rings. The valve casing members 71 and 72 
define a cylindrical auxiliary valve chamber 73 coaxial with the bore 51 
and having end faces spaced apart in a direction axially of the tube 56 
with an auxiliary pressure inlet port 73a in one end face and an auxiliary 
exhaust port 73b in the other end face. An auxiliary control port 73c and 
passage 73d communicates the auxiliary chamber with the cylinder means 16 
at one side of the feed piston 17 to apply an exhaust fluid pressure 
therefrom. The auxiliary valve casing members also define an auxiliary 
valve actuator cylinder 74 spaced axially from the auxiliary valve chamber 
73. An auxiliary valve member 75 is disposed in the auxiliary valve 
chamber 73 and is advantagously guidably mounted on the tube 56. The 
auxiliary valve member has axially spaced end faces that are spaced apart 
somewhat less that the spacing between the end faces of the valve chamber 
and the auxiliary valve member is axially movable from a first position 
communicating the auxiliary pressure inlet port 73a with the auxiliary 
control port 73 while blocking flow through the auxiliary exhaust port 
73b, to a second position as shown in FIG. 4 communicating the auxiliary 
control port 73c with the exhaust port 73b while blocking flow through the 
auxiliary inlet port 73a. The auxiliary valve member 75 has a reduced 
diameter axial extension 75a that extends through the exhaust port 73b and 
spaced upwardly therefrom to communicate the valve chamber with the valve 
cylinder 74. A valve actuating piston 78 is slidably mounted in valve 
cylinder 74 and engages the end of the extension 75a on the auxiliary 
valve member 75. A passage 59b in the plate member 59 communicates the 
control pressure chamber 56a with the valve actuating cylinder 74 at the 
side of the valve actuating piston 78 opposite the valve member 75. The 
valve casing member 72 has an exhaust passage 72a that communicates with 
the valve actuating cylinder 74 at the other side of the piston and also 
with the exhaust port 73b in the valve chamber. Exhaust passage 72a can 
conveniently be formed by drilling one or more generally radially 
extending holes through the valve casing member, and the exhaust passage 
72a communicates with the exhaust passage means 46 by way of a groove 81 
formed around the cylindrical bore 51 in the body 10 intermediate the ends 
of the bore 51. As best shown in FIGS. 4 and 5, the exhaust passage means 
is conveniently formed by a hole 46a drilled into the body from one end 
10f at a location to intersect the exhaust outlet 46, and a second hole 
46b drilled into the body from the side 10d at a location to intersect the 
hole 46a and the distribution recess 81. The outer ends of holes 46a and 
46b are closed by plugs after drilling. The exhaust passage means also 
includes a hole 46c drilled into the body from the side 10c at a location 
to communicate the pressure distribution recess 81 with a pressure 
distribution recess 85 around the main valve cylinder 41. The outer end of 
hole 46c is closed by a plug after drilling. 
As shown in FIG. 6, the sealing gland 43 in the main valve cylinder 41 has 
a downwardly opening axial passage 43a that communicates at its lower end 
with the main exhaust port 42b and lateral passages 43b that communicates 
with an external annular recess 43c in the sealing gland and which is 
adapted to register with the pressure distribution recess 85 formed around 
the valve bore 41 in the body to communicate the main exhaust port with 
the exhaust passage means 45. The auxiliary valve member 75 and valve 
actuating piston 78 are preferably formed of a resilient synthetic resin 
material. The auxiliary valve member 75 may, for example be formed of 
nylon and the auxiliary valve piston 78 formed of a polycarbonate plastic 
such as "Lexan". 
The body 10 is conveniently formed of an easily machinable material such as 
aluminum and, in accordance with another aspect of the present invention, 
the feed cylinder means 16 is advantageously formed by a sleeve 91 of a 
wear resistant material for example stainless steel, and which is disposed 
in one portion of the bore 51 between the valve casing member 71 and an 
annular piston head member 92. As best shown in FIG. 4, the valve casing 
member 71 is formed with a reduced diameter end portion 71a and one end of 
the sleeve 91 is adapted to be press fit on and sealed to that portion of 
the auxiliary valve casing member. The cylinder head member 92 is 
removably mounted in the bore and has a reduced diameter portion 92 
adapted to receive and center the other end portion of the sleeve 91. The 
piston rod slidably extends through the cylinder head member 92 and a 
means such as an O-ring is provided to form a sliding seal between the 
cylinder head member and the piston rod with a second O-ring at the outer 
periphery of the cylinder head member to form a seal with the cylinder 
bore 91. The cylinder head member is removably retained in the bore as by 
a split ring 94 and a lubricant retaining wiper 96 is disposed in the bore 
and retained in position as by a washer 97. 
The cylinder sleeve 91 has a outer diameter sufficiently smaller than the 
bore 51 to define a pressure chamber 98 in the bore and around the sleeve. 
The cylinder head member 92 is formed with one or more recesses 92b that 
are arranged to communicate the pressure chamber 98 with the interior of 
the sleeve at the rod side of the piston, to supply fluid pressure to the 
rod side of the piston and bias the latter in one direction. As previously 
described, the auxiliary valve means controls the application of fluid 
pressure to the other end face of the piston 17 to effect movement of the 
piston in the other direction. 
The pressure chamber 98 around the sleeve is also utilized to transmit 
fluid pressure to other parts of the feed apparatus. Thus, as shown in 
FIG. 4, the fluid pressure supply passage means in the valve body includes 
a hole 45a that is drilled into one side 10c of the valve body and which 
intersects the bore 51 to supply fluid pressure to the chamber 98. The 
hole 45a is also advantageously arranged to intersect a pressure 
distribution groove 36c that is formed around the cylinder 36 in the body 
10 at a level to communicate with the upper chamber 36b and supply fluid 
pressure to the upper chamber of the stock clamp actuating means. The 
pressure supply passage means also includes a hole 45b conveniently formed 
by drilling into the body 10 from the side 10d at a location to 
communicate with the bore 91 and to also intersect a pressure distribution 
groove 36c formed around the other clamp cylinder 36 to supply fluid 
pressure thereto. The outer end of hole 45b is closed by a plug. The 
pressure supply passage means also includes a third hole 45c conveniently 
formed by drilling into the body from the side 10d at a location to 
communicate at one end with the pressure chamber 98 and to intersect a 
chamber 41a at the lower end of the main valve cylinder 41, to supply 
fluid pressure to the inlet of the main control valve 19. The outer end of 
hole 45c is closed by a plug after drilling. 
The main control valve 44 has a stem 44a that extends upwardly through the 
sealing gland 43 and has an overtravel actuator 101 at its upper end. The 
fluid pressure in chamber 41a normally urges the main control valve to a 
raised position communicating the pressure inlet port with the control 
passage means 63 and the main valve member is operable to its second 
position in response to pressure applied to the upper end of the valve 
stem 44a. As disclosed in the aforementioned U.S. Pat. No. 3,038,645, the 
overtravel actuator 101 includes a head 101a on the upper end of the valve 
stem and a cup shaped member 101b having an open lower end slidably 
supported on the head 101a and sealed thereto as by an O-ring 101c. Stem 
44a has an axial passage 44b therethrough communicating at its lower end 
with the pressure chamber 41a and at its upper end with the interior of 
the cup-shaped member 101b to normally urge the cup-shaped member to a 
raised position. A means such as a split ring 102 limits upward movement 
of the cup-shaped member relative to the head 101a. Thus, fluid pressure 
is supplied to the cup-shaped member to normally urge it to a raised 
position and, when a downward force is applied to the upper end of the 
cup-shaped member 101b as by press ram, it initially moves the main 
control valve downwardly to its second position and further depression of 
the cup-shaped member accommodates overtravel of the press ram. 
From the foregoing it is thought that the construction and operation of the 
stock feed apparatus will be readily understood. The stock feed apparatus 
is adapted to be mounted on the punch press as by bolts or fasteners that 
extend through mounting holes 105 in the body 10. The fluid pressure 
passage means 45 is connected to a source of gaseous fluid pressure such 
as the plant air supply, and air under pressure is continuously supplied 
through passages 45a to the pressure chamber 98 around the sleeve and also 
through passages 45a and 45b to the upper chambers 36b of the fluid 
pressure actuators for the stock holding clamp to normally bias the stock 
holding clamp downwardly to a stock engaging position. Fluid pressure is 
also continuously supplied through passages 45c to the chamber at the 
lower end of the valve cylinder 41 and normally biases the main control 
valve to a raised position shown in FIG. 2. When the main control valve is 
in its raised position, it supplies fluid pressure through control outlet 
port 42c and main control passages 63, 63a and 64 to the lower chambers 
36a of the clamp actuating cylinders. The effective area at the rod end 
face of the clamp pistons 12a is smaller than the area at the lower face 
of the clamp pistons and, when fluid pressure is applied to the chamber 
36a it moves the clamp pistons upwardly to move the stock clamp 11 to its 
raised or stock disengaging position. When the main control valve supplies 
fluid pressure to the control passages it also pressurizes control chamber 
56a and supplies fluid pressure through tube 56 and passage 17b in the 
piston to the pressure chambers 34a in the feed head to move the feed 
clamp downwardly to a stock engaging position. When fluid pressure is 
applied to the control chamber 56a, it also actuates valve actuating 
piston 74 of the auxiliary control valve to move the auxiliary control 
valve 75 to the position shown in FIG. 4 communicating the auxiliary 
control outlet 73c with the exhaust port 73b and blocking flow from the 
auxiliary inlet 73a. Thus, under these conditions, fluid pressure is 
exhausted from the end of the feed cylinder opposite the rod 17a and the 
feed piston is moved to the left as shown in FIG. 4 under the fluid 
pressure applied to the rod end face of the feed piston. 
When the main control valve is moved down to its second or lower position 
shown in FIG. 6, it communicates the control outlet port 42c with the 
exhaust port 42b. Under these conditions, fluid pressure is exhausted from 
the chambers 36a at the lower side of the clamp pistons 12a so that the 
clamp pistons move downwardly under the fluid pressure that is 
continuously supplied to the upper rod end face of the clamp pistons. When 
the control valve is in its second position, it also exhausts fluid 
pressure from the upper chambers 34a of the stock feed cylinders and the 
springs 32 then move the stock feed clamp upwardly to a stock release 
position. When the main control valve is in its second position 
communicating the control with the exhaust outlet, it also exhausts fluid 
pressure from the valve actuating cylinder 74 and fluid pressure on the 
opposite end of the auxiliary valve member 75 moves the valve member and 
piston from the position shown in FIG. 4 to a position in which the valve 
member communicates the pressure inlet port 73a with the control port and 
closes the auxiliary exhaust port 73b. Fluid pressure is then supplied to 
the end of the feed cylinder to move the feed piston and feed head to the 
right as viewed in FIG. 4. Thus, the stock holding clamp is moved to a 
stock engaging position and the stock feed clamp is moved to a stock 
release position just prior to movement of the feed head to the right to 
an extended position against the stop 25a. The stock holding clamp is 
moved to its release position and the stock feed clamp to a stock engaging 
position when the feed head is moved to the left toward its retracted 
position as shown in FIG. 4. As will be seen, the length of the stroke of 
the feed head and hence the length of stock fed can be adjusted by the 
adjustable stop 25. As previously described, the strip guides 26 are 
laterally adjustable to accommodate stock of different widths. 
In the stock feed apparatus disclosed herein, it is only necessary to 
machine one bore in the body for both the feed piston and the auxiliary 
valve. The auxiliary valve including the auxiliary valve casing members 
and the auxiliary valve member and valve actuator piston can be easily 
formed on a screw machine and thereafter assembled in the bore. Mounting 
the auxiliary valve in the same bore with the feed cylinder also 
simplifies the formation of the various holes or passages for 
communicating the several valves and fluid actuators and feed pistons. The 
provision of a sleeve for the feed piston cylinder not only reduces wear 
problems but also simplifies the passage arrangement for supplying fluid 
pressure to the rod end of the cylinder. As shown, the passages can be 
easily formed by drilling holes that are orthogonal to the axis of the 
feed cylinder.