GB1600778A - Stock feeder for use with a punch press - Google Patents

Description

(54) STOCK FEEDER FOR USE WITH A PUNCH PRESS (71) I, ALBERT WILLIS SCRIBNER, a Citizen of the United States of America, of 6 Country Club Road, Darien, Connecticut 06820, United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to stock feeders for use with punch presses.

The invention provides a stock feeder for intermittently advancing stock into the work station of a punch press having a reciprocating ram: said feeder comprising a frame; a feed slide carried by said frame and mounted for movement through feed and index strokes in respective opposite directions; stock gripping means carried by said feed siide; first fluid motor means for actuating said feed slide; second fluid motor means for actuating said stock gripping means; valve means for controlling said fluid motor means, said valve means having first and second operative conditions; control means for said valve means including trigger means adapted to be operated in response to a retractive movement of the press ram for placing said valve means in its first operative condition for causing said first fluid motor means to move said feed slide through one of said strokes; and reversing means operable in response to the terminal portion of said one stroke of said feed slide means for causing said valve means to be shifted to its second operative condition for causing said first fluid motor means to move said feed slide means through the other one of said strokes in the opposite direction to said one stroke.

In order that the invention may be well understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings in which: Figures 1 and 2 are diagrammatic views illustrating the nature of the operation of certain prior art stock feeders for use with punch press; feeders.

Figures 3 and 4 are diagrammatic views illustrating the nature of the operation of the present feeder; Figure 5 is a plan view of the stock transport portion of the present feeder.

Figure 6 is a front elevational view, in partial axial section, of the appatatus of Figure 5.

Figure 7 is a sectional view of the feed slide taken along the transverse section line 7-7 of Figure 6.

Figure 8 is a plan view in partial section illustrating the feeder valve means and associated control means therefor and the construction and arrangement of the parts at the head end of the main cylinder of the feeder.

Figure 9 is a front elevational view illustrating the valve control means of Figure 8.

Figure 10 is a left side elevational view (with certain parts broken away) of a portion of the means shown in Figure 9.

Figure 11 is a sectional view of the valve means as taken along section line 11-11 of Figure 8.

Figure 12 is a rear elevational view of the valve means taken in the opposite direction to that of Figure 9.

Figures 13, 14 and 15 are front elevational fragmentary views diagrammatically illusttrating the sequence of operation of the feeder cycle trigger and reversing means that operatively shift the control valve during each cycle of operation of the present feeder.

Figures 1 and 2 diagrammatically illustrate aconventionaltype of control for feeders which are adapted to be controlled by the operation of the punch press. In such conventional feeders a valve control plunger 20 is adapted to be vertically displaced by the press ram, and a stock advancing feed slide 22 is adapted to be reciprocated between two fixed stops 23 and 24. When the feeder valve control plunger 20 is moved downwardly as indicated by arrow 21 the feed slide 22 will be displaced through a non-feed or index stroke as illustrated by arrow 25 of Figure 1, Thereafter during the following upward movement of the press ram the feeder valve control plunger moves upwardly as indicated by arrow 26 of Figure 2 whereby the feed slide 22 will be displaced through a feed stroke as illustrated by arrow 27 of Figure 2. In this type of control there is a feed slide movement in response to each downward movement of plunger 20 and in response to each upward movement of said plunger.

Figures 3 and 4 illustrate the control sequence for the present stock feeders. Here when the press ram moves downwardly the control plunger 30 of the feeder will be thereby moved downwardly as indicated by arrow 31 of Figure 3; however during this plunger movement the stock advancing slide 32 will remain in a normal rearward or indexed position as illustrated in Figure 3. When the control plunger 30 is permitted to move upwardly, as indicated by arrow 33 of Figure 4, in response to the upward movement of the press ram the feed slide 32 will be displaced first through a feed stroke and then automatically returned through a non-feed or index stroke to said normal indexed position, as indicated by arrow 34, and will remain there until the feeder is triggered again during the next upward stroke of the press ram. The Figure 3-4 type control thus provides for the semi-automatic sequencing of the feeder in response to each cycle of operation of the press ram without any need for output means from the control means for controlling the press.

Referring primarily to Figures 5, 6 and 7 the transport portion of the present feeder will be described first. The feeder frame may take any suitable form such as that shown in my U.S. Patent Specification No. 3,329,327 or may for example comprise a U-shaped frame member 38, Figure 5, having a main body portion 40, an end block portion 41 and a plate like portion 42 integral with the main body portion 40 and interconnecting the lower regions of said main body and end block portions 40 and 41. Slidably mounted on the flat upper surfaces of said plate like portion 42 is a stock advancing feed slide 43 that is formed with a central depending key portion 44 that slidably engages a T-slot guideway 45 centrally formed in said plate like portion 42; the key portion 44 being vertically retained in said guideway by any suitable means such as a headed screw and washer arrangement 46 as is illustrated in Figures 6 and 7. A stock gripping means is carried by said feed slide 43 and comprises a grip bar 50 which is biased upwardly to a normal stock releasing position shown in Figure 7 by suitable springs 51 and which is adapted to be moved downwardly by fluid motor means compressing two similar single acting fluid motors that are carried by said feed slide. Each such fluid motor includes a piston 52 that is slidably disposed in a grip cylinder 53 formed in the feed slide and an integral piston rod 54 that extends upwardly through the top of the feed slide and through a suitable hole formed in said stock grip bar 50. A suitable ring fastener 55 secures the bar 50 against a shoulder 56 of each piston rod 54. Any suitable sliding O-rings seals 57 are provided where and as needed. As will be apparent when fluid pressure is admitted to the top portions of the two fluid cylinders 53 the bar 50 will be moved downwardly against the action of springs 51 from its said stock release position to a stock gripping position.

The effective length of the feed stroke of feed slide 43 may be varied by means of a stroke adjusting screw 60 which threadedly extends through the said end block portion 41 and which may be secured in selected adjusted position by means of a lock nut 61 as is well understood in the art. The top of the end block portion 41 is formed with a transverse slot 62 in which a stock braking spring 63 is at least partially disposed, said spring having hooked ends that engage suitable holes such as 64, Figure 6, formed in the two end faces of said end block portion 41. This spring- groove arrangement is adapted to laterally guide and apply a light braking force to the stock, indicated by arrow 5 in Fig. 6, that is being fed through the feeder and between the spring 63 and the upper surface of said end block frame portion 41.

A first fluid motor means is provided for reciprocating the feed slide 43; such means comprising a main cylinder 70 formed in the said main body portion 40 and a piston 71 slidably disposed therein. A tubular piston rod 72 integrally connected to said piston 71 extends axially through a collar 73 that is press fitted or otherwise secured in the end of cylinder 70. The shouldered outer end of the piston rod is received in a similarly shaped hole formed through the feed slide, as is best illustrated in Figure 6, and a headed screw 74 which threadedly engages the outer end of the piston rod serves to secure said feed slide in fluid tight and fixed relation on and with respect to the said outer end of piston rod 72. The headed screw 74 and the outer end of the piston rod 72 are provided with suitable static fluid seals 75 as and where needed as illustrated in Figure 6, while the piston 71 and collar 73 are provided with suitable sliding fluid seals 76 where and as needed as is also illustrated in Figure 6. The opposite or forward end of the main cylinder 70 is closed by means of a plug 80, Figures 5 and 8, that is secured in the position shown by any suitable means such as a roll pin 81. As illustrated in Figure 8 the plug 80 is formed with passages that deliver pressure fluid to and from the main cylinder and the grip cylinders respectively and to this end a tube 82 is provided which is secured by any suitable means in a similarly shaped axially extending cy lindrical recess formed in the inner end of plug 80 and which telescopically cooperates with the tubular piston rod 72. The plug is also formed with a first right angled fluid conducting passage 83 that communicates at one end thereof with the inside of tube 82 and at the other end thereof with a first annular groove 84 formed in the outer cylindrical surface of said plug. Plug 80 is formed with a second similar annular groove 85 and a second right angled passage 86 that provides communication between said annular groove 85 and an annular recess 90 formed in the inner face of said plug. An annular projection 88 formed on the inner face of piston 71 is adapted to cooperate with said recess 90 so as to thereby afford a buffer or cushioning effect for the terminal portion of each feed stroke of the instant feeder. As will be seen pressure fluid may flow to and from the head end of the main cylinder 70 through the annular groove 85, passage 86 and recess 90, and to and from the second fluid motor means comprising the grip fluid motors carried by the feed slide through said annular groove 84, passage 83, and tube 82. The fluid conducting line for the gripper fluid motors is completed throslg'll the serially communicating passages defined by the tubular piston rod 72, Figure 6, the radially extending holes 91, Figures 6 and 7, and an annular groove 92 formed in the outer cylindrical wall of the end of said piston rod 72, and passages 93, 94 and 95, Figures 5, 6 and 7 formed in the feed slide 43. Three suitable static seals 100, 101 and 102, Figure 8, are provided on the plug 80 so as to insure the mutual isolation of the pressure fluid which flows through the annular grooves 85 and 84, respectively, and which actuates the main and gripper fluid motors respectively.

The main body portion 40 of the feeder frame is formed with horizontally extending passages 103 and 104, Figure 5, which respectively communicate with the said annular plug grooves 84 and 85 and with two vertical fluid conducting passages 105 and 106 respectively, Figures 5 and 6, that extend upwardly through the top surface of said main body portion 40. A third similar vertical passages 107 communicates with a lower horizontal passages 108 that in turn communicates with a fluid pressure supply line 109.

The inner end of line 109 communicates with the rod end of the main cylinder 70 while the outer end thereof is enlarged and threaded as indicated at 109a of Figures 5 and 9.

A mono-stable rotary four-way valve means of unit 110, Figures 8 and 11, is provided to control the flow of pressure fluid from supply lines 107-109 into and out of the said passages 105 and 106 so as to thereby properly sequence the operation of said main and gripper fluid motors. The valve means 110 comprises a valve block 111 that is secured to the said main body portion 40 by any suitable fastening means such as screws 112. Rotatably mounted in valve block 111 is a rotatable valve member of core 113 that is formed with two coplanar right angle passages 114, 115 as illustrated in Figure 11. The four ends of passages 114, 115 are effectively spaced 90 degrees apart around the periphery of valve core 113. The valve block is drilled horizontally so as to form passages 116 and 117 having coextensive axes that are disposed diametrally with respect to the valve block aperture that receives said valve core 113; and is drilled vertically so as to form passages 120, 121 having vertical coextensive axes that are also disposed diametrally wth respect to said valve block aperture. The inner ends of said passages 116, 117, 120 and 121 are effectively spaced 90 degrees apart. A vertical passage 122 formed in the valve block communicates with said passage 117, while a similar passage 123 communicates with said passage 116. As is shown in Figure 11 when the valve block 110 is secured in place on the main body portion 40 the lower ends of passages 121, 122 and 123 will communicate with the upper ends of said passages 107, 105 and 106 respectively. The valve core 113 is adapted to be oscillated through 90 degrees between two predetermined rotary positions so that the valve means may be placed in first and second operative conditions. In the normal clockwise position illustrated in Figure 11 and in which the valve means is in the second operative condition, pressure fluid will be supplied to and exhausted from the main fluid motor means and the gripper fluid motor means respectively, and the reverse is true when valve core 113 is turned counter-clockwise 90 degrees to place the valve means in its first operative condition.

Any suitable restriction may be provided in one of the lines between the valve and the head end of the main cylinder so as to control the speed and timing of the actuation of the first and second fluid motor means as is well understood in the art. The fluid conductive lines 103, 104, 108, 93 and 116 are plugged at their respective outer ends so as to prevent leakage from the fluid circuit.

Figure 8-10 illustrate the mechanical control means for oscillating or shifting the position of the valve core 113; which means includes triggers means comprising a vertically reciprocable feeder cycle triggering plunger means 130 that is slidably mounted on two spacer studs 131, 132 that are fixedly secured to the valve block 111 and frame main body portion 40 respectively, the plunger means being slidably retained on said studs by any suitable type fastener rings. A tension spring 133, Figures 9 and 10, secured between said stud 131 and a pin 134 carried by the plunger means serves to bias plunger means 130 to its normal upper position shown in Figures 9 and 10 as determined by engage ment of said studs 131, 132 with the respective lower ends of the vertical'slots 135 formed in said plunger 130. A latching means or driver pawl 136 is pivotally mounted on the inner side of plunger 130 by any suitable means such as a pin 137. A suitable torsion spring 140 serves to yieldably bias said pawl in a counter clockwise direction as seen in Figure 9 so that the lower edge thereof is urged into engagement with a pin 141 extending out from the end of the valve core 113 as is best seen in Figures 9 and 10. The driver pawl or latching means 136 is formed with a shoulder 142, Figure 9, that is adaped to cooperate with said valve core pin 141 during reciprocation of plunger means 130.

The inner end of the valve core 113 is provided with two diametrically opposed and inwardly extending pins 143 and 144. A valve biasing means comprising tension spring 145, Figure 12, which is connected between said pin 143 and a pin 146 secured to the valve block 111 so as to normally rotatably bias said valve core in a counter clockwise direction as seen in Figure 12 and in a clockwise direction as seen in Figure 9 so that valve core 113 assumes the normal position shown in Figures 9, 11 and 12 as determined by engagement of the valve core pin 144, Figure 12, with a suitable stop 147 that is secured by any suitable means to the valve block 111. The combination of the plunger means 130 and pawl 136 constitute actuat o means which is biased to a normal position by actuator biasing means comprising tor sion spring 140 and tension spring 133.

When the plunger means 130 is in its normal upper position illustrated in Figure 9 the lower end of the driver pawl or latch means 136 is disposed immediately in front of and substantially coplanar with respect to the adjacent end of a horizontal slide bar or trip reverse means 150 that is slidably carried on the side of the main body portion 40 by means of suitable pins 151 and 152 and associated fastener rings on the latter. The slide bar is yieldably biased to a normal right hand position seen in Figure 9 by means of a spring 153 that is secured between said pin 152 and a pin 154 fixed on said slide bar 150; this normal position being determined by the engagement of the said pins 151, 152 with the left ends of the respectively associated slots 156 formed in said slide bar 150. The outer or right end 157 of slide bar 150 as seen in Figure 9 is adapted to be engaged and displaced to the left as seen in Figure 9 by a pin 160, Figures 5 and 7, fixed to the side of feed slide 43 during the terminal portion of each feed stroke of the said feed slide 43; this leftward movement of the bar 150 serving to displace the said pawl 136 in a clockwise direction, as seen in Figure 9, against the action of said spring 140. It will be noted that the time required for valve core 113, once released, to be spring returned to its feed normal position in Figure 12, affords a short time delay which ensures that a feed stroke is fully completed before a non-feed or index stroke commences.

The operation of the feeder will now be described. When pressure fluid is supplied to the line 109 the rod end of the main cylinder will be continuously biased by said pressure fluid and thus the feed slide 43 will be continuously urged in the feed direction as indicated by arrow 165 of Figure 5. In the normal Figure 11 or second operative condition of the valve means pressure fluid may flow from said supply line 109 through lines 108, 107, 121, 115, 116, 123, 106, 104, 85, 86 and 90 to the head end of the main cylinder whereby the feed slide will be displaced in a non-feed direction as indicated by arrow 166 of Figure 5 to a normal indexed position determined by engagement of the slide 43 with the inner end of the stroke adjustment screw 60 as seen in Figure 5. As will be apparent from Figure 11 the valve core will simultaneously permit the exhaust of fluid pressure from the gripper motors on the feed slide 43 through lines 95, 94, 93, 92, 91, piston rod 72, tube 82 lines 83, 84, 103, 105, 122, 117, 114 and finally to the valve exhaust hole 120; thus the grip bar 50 will be moved by springs 51 to its upper or stock releasing position shown in Figure 7. In this normal indexed position of the feed slide 43 the stock to be fed (generally indicated by arrow 5 of Figure 6) is yieldably held stationary by the light frictional braking action of spring 63, Figures 5 and 6. The vertically reciprocable plunger means 130 is adapted to be actuated by the vertical motion of the press ram whereby during the downward movement of said ram the plunger 130 will be displaced downwardly, against the action of spring 133, from its normal upper Figure 9 position as indicated by arrow 167 of Figure 13 until the pawl shoulder 142 swings underneath the valve core pin 141 as is diagrammatically illustrated in Figure 13. During this downward movement of plunger means 130 there is no resulting shift in the rotary position of valve core 113 and hence the feed slide 43 remains in its indexed position shown in Figure 5.

During the ensuing retractive or upward movement of the press ram plunger spring 133 will cause the plunger 130 to move upwardly, as indicated by arrow 168 of Figure 14, to its said normal upper position thereby causing the pawl 136 to displace the valve core 113 in a counter clockwise direction through 90 degrees as indicated by arrow 170 of Figure 14 placing the valve means in a first operative condition. The spring 133 is effectively stronger than spring 145, Figure 12. The 90 degree shift of the valve core position from its normal Figure 11 position will now cause pressure fluid to be supplied to the said stock gripper fluid motors carried by the feed slide and to be exhausted from the head end of the main cylinder 70 whereby the feed slide is displaced through a feed stroke in said feed direction 165 of Figure 5. During the terminal portion of this feed stroke the reversing means is operated when the feed slide pin 160 engages and displaces the trip slide bar 150 to the left as seen in Figure 9 so that the slide bar displaces the driver pawl 136 in a clockwise direction as seen in Figure 9. This displacement of pawl 136 will move the pawl shoulder 142 out from under the valve core pin 141, as is diagrammatically illustrated in Figure 15, so that the spring 145, Figure 12, is now free to return the now released valve core 113 through 90 degrees to its normal position as indicating by arrow 175 of Figure 15. When the valve core thus snaps back to its said normal Figure 11 position the feed slide will again more through a nonfeed stroke and return to its said normal Figure 5 position, and the trip slide bar 150 and pawl 136 will also return to their respective normal Figure 9 positions under the action of springs 153 and 140 respectively. The feed slide 43 will remain in said normal indexed or Figure 5 position until the next operative cycle of the press produces the next semi-automatic cycling of the instant feeder in a manner similar to that just described.

The principal advantages of the present construction and arrangement are, first no complex interfacing is required between the present semi-automatic feeder and the press; the only requirement here being that the press ram simply operate the plunger means 130.

Secondly the relatively simple feeder cycle triggering action of the upward motion of driver pawl 136, as illustrated in Figure 14, and the equally simple and direct reversing or valve tripping action afforded by the leftward motion of the trip slide bar 150, as illustrated in Figure 15, permits a reliable fast acting control for oscillating the valve means so as to produce an efficient semiautomatic control means for the feed slide movement as described in connection with Figures 3 and 4. Thirdly the construction and operation of the present valve and valve control linkage is such as to afford a semiautomatic action for the feeder at only a minor increase in cost over that for a feeder that operates in the conventional manner described in connection with Figures 1 and 2.

WHAT I CLAIM IS:- 1. A stock feeder for intermittently advancing stock into the work station of a punch press having a reciprocating ram: said feeder comprising a frame; a feed slide carried by said frame and mounted for movement through feed and index strokes in respective opposite directions stock gripping means carried by said feed slide; first fluid motor means for actuating said feed slide; second fluid motor means for actuating said stock gripping means; valve means for controlling said fluid motor means, said valve means having first and second operative conditions; control means for said valve means including trigger means adapted to be operated in response to a retractive movement of the press ram for placing said valve means in its first operative condition for causing said first fluid motor means to move said feed slide through one of said strokes; and reversing means operable in response to the terminal portion of said one stroke of said feed slide means for causing said valve means to be shifted to its second operative condition for causing said first fluid motor means to move said feed slide means through the other one of said strokes in the opposite direction to said one stroke.

2. A feeder as claimed in claim 1, wherein when said valve means is in its first operative condition said first fluid motor means is adapted to move said feed slide means through a feed stroke, and when said valve means is in its said second operative condition said first fluid motor means is adapted to move said feed slide means through an index stroke.

3. A feeder as claimed in claim 1, wherein said valve means when in its second operative condition is adapted to cause said first fluid motor means to move said feed slide through an index stroke and back to a normal indexed position where it will normally remain until said trigger means is again operated in response to the next retractive movement of said press ram.

4. A feeder as claimed in claim 2, wherein said trigger means comprises a plunger means adapted to reciprocate in synchronism with the press ram, wherein said feed slide moves through one and only one feed stroke in response to each reciprocation of said plunger means, and wherein each feed stroke of said feed slide is initiated only in response to the reciprocation of said plunger means.

5. A feeder as claimed in claim 3, wherein said feed slide moves through one and only one feed stroke in response to each operation of said trigger means, and wherein said control means includes no output means for controlling said press.

6. A feeder as claimed in claim 1, 2, 3 or 5 wherein said trigger means comprises a plunger means adapted to be moved downwardly from a normal upper position in response to a downward movement of the press ram and adapted to be returned upwardly to said normal position in response to a retractive movement of the press ram.

7. A feeder as claimed in claim 1, 2, 3 or 5, wherein said trigger means comprises a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (24)

**WARNING** start of CLMS field may overlap end of DESC **. and to be exhausted from the head end of the main cylinder 70 whereby the feed slide is displaced through a feed stroke in said feed direction 165 of Figure 5. During the terminal portion of this feed stroke the reversing means is operated when the feed slide pin 160 engages and displaces the trip slide bar 150 to the left as seen in Figure 9 so that the slide bar displaces the driver pawl 136 in a clockwise direction as seen in Figure 9. This displacement of pawl 136 will move the pawl shoulder 142 out from under the valve core pin 141, as is diagrammatically illustrated in Figure 15, so that the spring 145, Figure 12, is now free to return the now released valve core 113 through 90 degrees to its normal position as indicating by arrow 175 of Figure 15. When the valve core thus snaps back to its said normal Figure 11 position the feed slide will again more through a nonfeed stroke and return to its said normal Figure 5 position, and the trip slide bar 150 and pawl 136 will also return to their respective normal Figure 9 positions under the action of springs 153 and 140 respectively. The feed slide 43 will remain in said normal indexed or Figure 5 position until the next operative cycle of the press produces the next semi-automatic cycling of the instant feeder in a manner similar to that just described. The principal advantages of the present construction and arrangement are, first no complex interfacing is required between the present semi-automatic feeder and the press; the only requirement here being that the press ram simply operate the plunger means 130. Secondly the relatively simple feeder cycle triggering action of the upward motion of driver pawl 136, as illustrated in Figure 14, and the equally simple and direct reversing or valve tripping action afforded by the leftward motion of the trip slide bar 150, as illustrated in Figure 15, permits a reliable fast acting control for oscillating the valve means so as to produce an efficient semiautomatic control means for the feed slide movement as described in connection with Figures 3 and 4. Thirdly the construction and operation of the present valve and valve control linkage is such as to afford a semiautomatic action for the feeder at only a minor increase in cost over that for a feeder that operates in the conventional manner described in connection with Figures 1 and 2. WHAT I CLAIM IS:-

1. A stock feeder for intermittently advancing stock into the work station of a punch press having a reciprocating ram: said feeder comprising a frame; a feed slide carried by said frame and mounted for movement through feed and index strokes in respective opposite directions stock gripping means carried by said feed slide; first fluid motor means for actuating said feed slide; second fluid motor means for actuating said stock gripping means; valve means for controlling said fluid motor means, said valve means having first and second operative conditions; control means for said valve means including trigger means adapted to be operated in response to a retractive movement of the press ram for placing said valve means in its first operative condition for causing said first fluid motor means to move said feed slide through one of said strokes; and reversing means operable in response to the terminal portion of said one stroke of said feed slide means for causing said valve means to be shifted to its second operative condition for causing said first fluid motor means to move said feed slide means through the other one of said strokes in the opposite direction to said one stroke.

2. A feeder as claimed in claim 1, wherein when said valve means is in its first operative condition said first fluid motor means is adapted to move said feed slide means through a feed stroke, and when said valve means is in its said second operative condition said first fluid motor means is adapted to move said feed slide means through an index stroke.

3. A feeder as claimed in claim 1, wherein said valve means when in its second operative condition is adapted to cause said first fluid motor means to move said feed slide through an index stroke and back to a normal indexed position where it will normally remain until said trigger means is again operated in response to the next retractive movement of said press ram.

4. A feeder as claimed in claim 2, wherein said trigger means comprises a plunger means adapted to reciprocate in synchronism with the press ram, wherein said feed slide moves through one and only one feed stroke in response to each reciprocation of said plunger means, and wherein each feed stroke of said feed slide is initiated only in response to the reciprocation of said plunger means.

5. A feeder as claimed in claim 3, wherein said feed slide moves through one and only one feed stroke in response to each operation of said trigger means, and wherein said control means includes no output means for controlling said press.

6. A feeder as claimed in claim 1, 2, 3 or 5 wherein said trigger means comprises a plunger means adapted to be moved downwardly from a normal upper position in response to a downward movement of the press ram and adapted to be returned upwardly to said normal position in response to a retractive movement of the press ram.

7. A feeder as claimed in claim 1, 2, 3 or 5, wherein said trigger means comprises a

plunger means that is yieldably biased to a normal position.

8. A feeder as claimed in claim 1, 2, 3 or 5, wherein said trigger means comprises plunger means and a pawl that is carried by said plunger means.

9. A feeder as claimed in claim 1, 2, 3 or 5, wherein said trigger means comprises actuator means and actuator biasing means adapted to bias said actuator means to a normal position, said actuator means when yieldably returned to its normal position causing said valve means to be shifted to its first operative condition.

10. A feeder as claimed in claim 9, wherein said reverse means includes means adapted to effectively disable said actuator means so as to cause said valve means to be shifted to its second operative condition.

11. A feeder as claimed in any one of the preceding claims, wherein said valve means comprises a valve member that is adapted to be rotatably oscillated in alternate clockwise and counter-clockwise directions between two predetermined rotary positions.

12. A feeder as claimed in any one of the preceding claims, wherein valve biasing means is provided for yieldably biasing said valve means to its second operative condition, and wherein said trigger means when operated causes said valve means to be moved to its first operative condition against the action of said biasing means, and wherein said reversing means when operated is adapted to permit said valve means to be returned to its said second operative condition by the action of said biasing means.

13. A feeder as claimed in claim 1 or 2, wherein said trigger means comprises plunger means adapted to be reciprocally moved away from and towards a normal position in response to the downward and upward move ments respectively of said press ram, and means operated by said plunger means adap ted to shift the operative condition of said valve means in response to said movement of said plunger means toward its normal position so as to cause said feed slide to move through one of its strokes.

14. A feeder as claimed in claim 13, wherein said valve means comprises a rotary valve member, and wherein said means for shifting the operative condition of the valve comprises a pawl that is carried by said plunger means.

15. A feeder as claimed in any one of the preceding claims, wherein said reversing means comprises a slide bar that is adapted to be displaced in response to the terminal por tion of said one stroke of said feed slide means.

16. A feeder as claimed in claim 1 or 2, wherein said valve means includes a rotatable valve member, and wherein said trigger means comprises a movable pawl that is operative to cause said rotatable valve member to be rotated from one predetermined rotary position to another to cause said feed slide to move through said one stroke, and wherein said reversing means comprises means for causing said rotatable valve member to be rotated back to said one predetermined rotary position to cause said feed slide to move through said other stroke in the opposite direction to said one stroke.

17. A feeder as claimed in claim 1 or 2, wherein said trigger means comprises drive means for rotatably actuating said valve means.

18. A feeder as claimed in claim 17, wherein said drive means comprises plunger means and a pawl that is carried by said plunger.

19. A feeder as claimed in claim 1 or 2, wherein said valve means comprises a rotatable valve member having two predetermined rotary positions, wherein said trigger means comprises means for causing said rotatable valve member to be rotated to one of its rotary positions, and wherein said reversing means comprises means for causing said rotatable valve member to be rotated to the other one of its rotary positions.

20. A feeder as claimed in any one of the preceding claims, wherein said feed slide is adapted to be continuously biased in a stock feed direction.

21. A feeder as claimed in any one of the preceding claims, wherein said frame is substantially U-shaped and comprises a main body portion, an end block portion, and an intermediate plate-like portion on which said feed slide reciprocates, said plate-like portion being integrally formed with said main block portion.

22. A feeder as claimed in any one of the preceding claims, wherein said valve means comprises a four way valve.

23. A feeder as claimed in any one of the preceding claims, wherein the valve means controls the second fluid motor means to cause said stock gripping means to grip the stock during feed strokes of the feed slide and to release stock during index strokes of the feed slide.

24. A stock feeder for intermittently advancing stock into the work station of a punch press having a reciprocating ram, substantially as herein described with reference to the accompanying drawings.