US3686992A

US3686992A - Turret indexing mechanism

Info

Publication number: US3686992A
Application number: US112859A
Authority: US
Inventors: Dennis Daniels
Original assignee: Amada Ltd Us
Current assignee: US Amada Ltd
Priority date: 1971-02-19
Filing date: 1971-02-19
Publication date: 1972-08-29
Anticipated expiration: 1989-08-29
Also published as: HK12776A; ZA72733B; CA963801A; GB1378183A; JPS5325975B1

Abstract

A pneumatic-hydraulic control is coupled with either a manually or numerically controlled punch press to rotate the turrets of the press to the proper positions. Pneumatic pressure is directed selectively to one of two fluid accumulators to force fluid from that accumulator through an open deceleration valve to drive a piston which in turn is coupled to a rack and pinion drive for rotating the turrets. The other side of the piston is exhausted through an open deceleration valve to the other fluid accumulator. A slider switch having a central stop contactor and two deceleration contactors is secured to the rack and moves with the rack across a linear multi-contact slidebar. One of the contactors on the slidebar corresponding with the desired station on the turret is energized. A deceleration contactor engaging the energized contact closes the deceleration valve of the driving fluid accumulator forcing the fluid to go through a restricted passage thus decelerating the turret drive. The stop contactor engaging the energized contact exhausts both fluid accumulators to stop the turret drive.

Description

United States Patent Daniels 1 Aug. 29, 1972 1541 TURRET INDEXING MECHANISM 72 Inventor: Dennis Daniels,Williamsville,N.Y. [73] Assignee: U.S. Amada, Ltd., Seattle,- Wash.

22 Filed: Feb. 19,1971

21 Appl.No.: 112,859

[52] US. Cl. ..83/55l, 83/71, 83/552, 83/559 [51] Int. Cl. ..B26d 5/04 [58] Field of Search ..83/55l, 552, 559, 71

[56] References Cited UNITED STATES PATENTS 3,377,887 4/1968 Nelson et a1 ..83/552 X 3,449,991 6/1969 Daniels ..83/552 X 3,527,130 9/1970 Knehans ..83/552 X Pn'mary ExaminerFrank T. Yost Att0meySeed, Berry & Dowrey ABSTRACT A pneumatic-hydraulic control is coupled with either a manually or numerically controlled punch press to rotate the turrets of the press to the proper positions. Pneumatic pressure is directed selectively to one of two fluid accumulators to force fluid from that accumulator through an open deceleration valve to drive a piston which in turn is coupled to a rack and pinion drive for rotating the turrets. The other side of the piston is exhausted through an open deceleration valve to the other fluid accumulator. A slider switch having a central stop contactor and two deceleration contactors is secured to the rack and moves with the rack across a linear multi-contact slidebar. One of the contactors on the slidebar corresponding with the desired station on the turret is energized. A deceleration contactor engaging the energized contact closes the deceleration valve of the driving fluid accumulator forcing the fluid to go through a restricted passage thus decelerating the turret drive. The stop contactor engaging the energized contact exhausts both fluid accumulators to stop the turret drive.

5Claims,3DrawingFigures PATENTEDwczs m2 3,686,992

INVENTOR. DENNIS DANIELS ATTORNEYS TURRET INDEXING MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to punch presses and particu larly to the control and indexing mechanism for positioning the turrets of punch presses.

2. Description of the Prior Art The turrets as used with punch presses include two co-axially aligned circular discs, each having its own independent axle and bearing housing on which they rotate. The discs are positioned apart from each other to allow the work-piece which is to be punched to pass between. The upper disc is the punch carrier and the lower disc is a die carrier.

At the time of punching the related punches and dies are precisely aligned by means of shot-pins acting into bushings in the circular discs. The bushings are so placed to correspond to each radial station of the turrets. Therefore, to drive the turrets around to the selected position, first the shot-pins must be withdrawn, and then through a motor and transmission arrangement rotation will take place. The two common methods heretofore used to obtain this motion are: (1) an electrical motor with clutch arrangement and (2) an hydraulic motor with related control valves and pump drive system.

To achieve the necessary high speed turret index dictated by modern NC controls, it is necessary to rotate the turrets at a very high speed, which puts a heavy burden on the deceleration factors prior to reaching final position.

SUMMARY OF THE INVENTION It is an object of this invention to provide a technique for rapidly indexing punching turrets.

It is another object of this invention to provide an apparatus for indexing turrets by the use of inexpensive and readily available shop pneumatic pressure.

It is another object of this invention to provide a turret indexing apparatus which combines readily available shop pneumatic pressure with more readily controllable hydraulic fluid to control the speed and amount of rotation of punching turrets.

Basically the apparatus includes control means for directing pneumatic pressure to one of two fluid accumulators. The pressurized fluid accumulator drives fluid through an open deceleration valve to a piston which in turn is coupled to a turret rotating means. Station approach sensing means are coupled to the turret rotating means to sense the oncoming presence of a position command signal associated with a particular station on the turrets to close the deceleration valve on the driving fluid accumulator, forcing the fluid through a restricted passageway to decelerate the turret drive means. Next a stop sensing signal is transmitted by the position command signal to exhaust both fluid accumulators thus stopping'the turret drive means. The shotpins may then be placed in the turrets to finalize the position and lock the turrets in place.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of a punch press embodying the principles of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a conventional C-frame punch press 10 having a work-piece holder 12 and work-piece positioning means 14. The punch press is provided with a pair of turrets 16 which rotatably position a variety of tools beneath the striker on the punch press.

The turrets include an upper disc 20 and a lower disc 21 each respectively mounted by its own axle and

bearings

23 and 24. The upper disc 20 contains a plurality of circumferentially spaced punches 26 whereas the lower disc includes a plurality of circumferentially spaced dies 28 alignable beneath the punches 26. The discs are locked and accurately positioned in place by shot-pins 30 acting in a conventional manner in bushings 32 corresponding to the various stations'on the turrets.

The indexing mechanism of this invention includes a solenoid actuated spring-centered four-way rotation valve 38 movable into the lefthand and righthand position, respectively, by

solenoids

39 and 40. Air at readily available shop pressures is introduced through an intake line 42 and is exhausted through an exhaust line 44. The valve is coupled to a pair of accumulators 46 and 48 each containing a quantity of hydraulic fluid F. Fluid accumulator 46 has a lower passageway 50 connected to a bypass leg 52 in which is positioned a manually-controlled conventional flow control valve 54. A solenoid controlled deceleration valve56 is positioned in the lower passageway in parallel with the bypass leg. The lower passageway connects to one end of an hydraulic cylinder 58.

The other accumulator 48 is provided with a lower passageway 60 having a bypass leg 62 in which is positioned a conventional manual flow control valve 64. A solenoid controlled deceleration valve 66 is provided in the lower passageway in parallel with the flow control valve 64. The lower passageway 60 is connected to the other end of the cylinder 58.

A piston 70 is slidably received in the cylinder 58 and g is secured to a piston rod 72 which in turn is secured to a plate 74. In the preferred form of the invention, as illustrated in FIG. 2, the plate 74 is rigidly secured to a rack and pinion drive 76 coupled to the

axles

23 and 24 of the turrets. Thus reciprocation of the piston 70 will simultaneously rotate the two turrets. The stroke of the piston will be equivalent to 360 of rotation of the turrets.

A slide switch 80 is rigidly secured to the rack of the top turret for linear movement along a slidebar 82. The slide switch is provided with a central stop contactor 84 and two spaced

deceleration contactors

85 and 86. The slidebar is provided with a plurality of spaced position command contacts 88 each corresponding to a station on the turrets and each electrically coupled to either a NC control 90 or a manual control 91. Engagement of the energized position command contact by one of contactors will complete a circuit for operating the various deceleration valves and the rotation valve 38.

In operation the leading

deceleration contactor

85 or 86, depending upon the direction of movement of the piston 70, will first engage the energized position command contact 88. At this point an electrical signal is transmitted to a deceleration valve closing the valve to force the fluid in the lower passageway through the related flow control valve to reduce the rate of movement of the piston 70. The central stop contactor then engages the energized position command contact at the decelerated rate and signals the rotation control valve to return to its center exhaust position so that the piston is stopped. The shot-pins 30 may then be driven into the bushings 32 to align and position the turrets at the proper station.

As a typical example assume the position command contact 88 furthest to the left in FIG. 2 is energized. The numerical control will also energize the solenoid 40 directing air through line 42 to the accumulator 48. Hydraulic fluid F will be forced through the unrestricted lower passageway 60 to therighthand side of the cylinder 58 driving the piston and thus the racks of the rack and pinion drive 76 also to the left. When the contactor 86 makes contact with the energized contact 88 a signal will be sent to close the deceleration valve 66 forcing the fluid through the bypass leg 62 and flow control valve 64. Since the rate of flow is reduced the piston will decelerate but will continue moving to the left. Next the central stop contactor 84 will engage the energized contact signally the rotation valve to return to its center position so that all motion stops. Then the shot-pin may be inserted in the bushings as earlier described.

FIG. 3 illustrates a modified form of drive for rotating the turrets and 21..In this form of the apparatus a conventional rotary actuator 158 is connected to the

lower passageways

50 and 60. The rotary actuator is of the type suitable for two way rotation. The rotary shaft 172 of the rotary actuator is coupled to a belt and sprocket drive 176 which is coupled to the

axles

23 and 24 of the turrets. A slideswitch 80 engages a slidebar 82 in the same manner as in the preferred embodiment.

Although the preferred forms of the invention have been illustrated and described it should be understood that the apparatus is capable of modification by one skilled in the art without departing from the principles of the invention. Accordingly, the scope of the invention is to be limited only by the literal interpretation of the claims appended hereto.

I claim:

1. In a punch press having a pair of turrets provided with circumferentially spaced stations positionable beneath a punch striker, a turret indexing mechanism comprising drive means for rotating the turrets simultaneously to position a selected station beneath the punch striker, said drive means including a pair of fluid accumulators each having a reservoir of hydraulic fluid and an upper end for receiving pressurized air, control means coupled to each accumulator upper end for selectively pressurizing or exhausting the air on the hydraulic fluid, an hydraulic actuator having a powered member for rotating the turrets, means coupling the hydraulic fluid in said accumulators with said hydraulic actuator for moving said powered member selectively in opposite directions, flow control means in said cou in means 0 erable t restrict the flow of fluid ther m, rst mean s for sensing the close approach of a station on the turrets to a punching position and operable to energize said flow control means for decelerating the powered member and for sensing the presence of a station on the turret at the punch location for stopping said powered member thus stopping said station beneath the punching position.

' 2. The punch press of claim 1 said coupling means in- I cluding a lower fluid passageway connected to each accumulator and having a bypass leg, a deceleration control valve in said passageway and variable restriction valve in said bypasses in parallel with said deceleration valve, said sensing means for sensing the close approach of a station to thepunch location being operable to energize said deceleration valve for forcing the flow through the flow restriction valve in the bypass leg.

3. The punch press of claim 1 wherein said hydraulic actuator is a linear cylinder and said powered means includes a piston and piston rod within said cylinder.

4. The punch press of claim 1 said hydraulic actuator including a rotary actuator, said powered means including a rotary output shaft of said rotary actuator.

5. The punch press of claim 1 said sensing means including a switch coupled to said powered member and having a central stop contactor and two deceleration contactors, a slider bar having a plurality of spaced contacts corresponding to the various stations of the turrets when positioned beneath the punch striker, the leading deceleration contactor, dependent upon the direction of travel of the powered member, first con-

Claims

1. In a punch press having a pair of turrets provided with circumferentially spaced stations positionable beneath a punch striker, a turret indexing mechanism comprising drive means for rotating the turrets simultaneously to position a selected station beneath the punch striker, said drive means including a pair of fluid accumulators each having a reservoir of hydraulic fluid and an upper end for receiving pressurized air, control means coupled to each accumulator upper end for selectively pressurizing or exhausting the air on the hydraulic fluid, an hydraulic actuator having a powered member for rotating the turrets, means coupling the hydraulic fluid in said accumulators with said hydraulic actuator for moving said powered member selectively in opposite directions, flow control means in said coupling means operable to restrict the flow of fluid therein, first means for sensing the close approach of a station on the turrets to a punching position and operable to energize said flow control means for decelerating the powered member and for sensing the presence of a station on the turret at the punch location for stopping said powered member thus stopping said station beneath the punching position.

2. The punch press of claim 1 said coupling means including a lower fluid passageway connected to each accumulator and having a bypass leg, a deceleration control valve in said passageway and variable restriction valve in said bypasses in parallel with said deceleration valve, said sensing means for sensing the close approach of a station to the punch location being operable to energize said deceleration valve for forcing the flow through the flow restriction valve in the bypass leg.

5. The punch press of claim 1 said sensing means including a switch coupled to said powered member and having a central stop contactor and two deceleration contactors, a slider bar having a plurality of spaced contacts corresponding to the various stations of the turrets when positioned beneath the punch striker, the leading deceleration contactor, dependent upon the direction of travel of the powered member, first contacting the energized contact to signal the approach of the station beneath the punch striker, and said central stop contactor being operable to engage the energized contact for deenergizing said control means to exhaust the air in both accumulators to stop said powered means.