US3883938A

US3883938A - Fluid-powered crimping press

Info

Publication number: US3883938A
Application number: US447555A
Authority: US
Inventors: Alfred W Schmidt; Richard B Freeman
Original assignee: Individual
Current assignee: Fabco Air Inc
Priority date: 1974-03-04
Filing date: 1974-03-04
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20

Abstract

A fluid-powered crimping press for tape-carried workpieces, such as electrical terminals, which are indexed to a crimping position where a conductor wire or lead is inserted in the barrel of the terminal and secured by the crmping operation. The crimping ram is powered by a hydraulic cylinder and the feed mechanism for indexing the tape-carried workpieces is also powered by a hydraulic cylinder, both of which are correlated in their operations by means of a series of hydraulic as well as electrically-operated valves, so as to provide a sequence of operation whereby the crimping ram is mechanically advanced to the workpiece while the feeding mechanism completes the advance of the tape to the appropriate index position for the crimping operation. During this movement of the crimping ram, the ram actuating cylinder is free of hydraulic pressure. An electrically-operated safety switch prevents any crimping actuation of the press unless the ram is in its fully lowered position. Actuation of the press can be accomplished manually by an operator or can be accomplished automatically in response to insertion of the conductor wire into the barrel of the terminal to be crimped. Upon actuation, fluid pressure is directed to the ram cylinder to create a crimping thrust of the ram which continues until a predetermined pressure level is reached in the ram cylinder which is sensed by a pressure relief valve. When the pressure relief valve is triggered, it actuates other valves of the system which cause the crimping pressure in the cylinder to be relieved and directed to the opposite side of the ram piston to cause retraction of the crimping ram and also operates a valve affecting the cylinder for the feed mechanism to cause retraction or resetting of the feed mechanism. When the ram has been fully retracted under pressure, it causes another hydraulic signal to be triggered which relieves the fluid pressure in the ram cylinder while at the same time actuating the feed cylinder to cause advance of the tape for the next crimping operation. As soon as the pressure on the ram cylinder has been relieved, spring means cause mechanism downward movement of the ram into engagement with the newly advanced workpiece so as to permit initiation of another operating cycle.

Description

United States Patent Schmidt et al.

[4 1 May 20, 1975 FLUID-POWERED CRIMPING PRESS [76] Inventors: Alfred W. Schmidt, PO. Box 787,

Keystone Heights, Fla. 32656; Richard B. Freeman, 3354 Dorchester Rd., Shaker Heights, Ohio 44120 [22] Filed: Mar. 4, 1974 [21] Appl. No.: 447,555

[52] US. Cl. ..29/203 DT; 92/152 [51] Int. Cl B2lf 15/00 [58] Field of Search ..29/203; 140/105; 92/152;

[56] References Cited UNITED STATES PATENTS 3,383,754 5/1968 Klenz 92/152 3,423,815 1/1969 Spangler et al. 29/203 Primary Examiner-Lowell A. Larson Attorney, Agent, or Firmlsler & Ornstein 57 ABSTRACT A fluid-powered crimping press for tape-carried workpieces, such as electrical terminals, which are indexed to a crimping position where a conductor wire or lead is inserted in the barrel of the terminal and secured by the crmping operation. The crimping ram is powered by a hydraulic cylinder and the feed mechanism for indexing the tape-carried workpieces is also powered by a hydraulic cylinder, both of which are correlated in their operations by means of a seriesof hydraulic as well as electrically-operated valves, so as to provide a sequence of operation whereby the crimping ram is mechanically advanced to the workpiece while the feeding mechanism completes'the advance of the tape to the appropriate index position for the crimping operation. During this movement of the crimping ram, the ram actuating cylinder is free of hydraulic pressure. An electrically-operated safety switch prevents any crimping actuation of the press unless the ram is in its fully lowered position. Actuation of the press can be accomplished manually by an operator or can be accomplished automatically in response to insertion of the conductor wire into the barrel of the terminal to be crimped.

Upon actuation, fluid pressure is directed to the ram cylinder to create a crimping thrust of the ram which continues until a predetermined pressure level is reached in the ram cylinder which is sensed by a pressure relief valve. When the pressure relief valve is triggered, it actuates other valves of the system which cause the crimping pressure in the cylinder to be relieved and directed to the opposite side of the ram piston to cause retraction of the crimping ram and also operates a valve affecting the cylinder for the feed mechanism to cause retraction or resetting of the feed mechanism. When the ram has been fully retracted under pressure, it causes another hydraulic signal to be triggered which relieves the fluid pressure in the ram cylinder while at the same time actuating the feed cylinder to cause advance of the tape for the next crimping operation. As soon as the pressure on the ram cylinder has been relieved, spring means cause mechanism downward movement of the ram into engagement with the newly advanced workpiece so as to permit initiation of another operating cycle.

18 Claims, 9 Drawing Figures PATENTEB unemrs IIHI lllll PATENIED W20 59$ SHED PATENTEB HAY 20 I975 SHEET 5 OF 6 PATtmEnuAvzmsrs 3,883,938

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6 or 6 MAIN FLUID-POWERED CRIMPING PRESS BACKGROUND OF THE INVENTION The invention is directed to production line crimping of workpieces, such as electrical terminals which are tape-mounted and indexed sequentially to crimping position.

Crimping presses of a mechanical or electrical or hydraulic nature are known to the art, as is also the concept of utilizing a belt or band of uniformly spaced workpieces on a tape carrier for the purpose of conveniently feeding the workpieces to the press. The workpieces, such as electrical terminals or connectors, have conductor wires or leads which must be secured to them individually by a crimping operation on the tubular barrel of the workpiece. Various means have been proposed for accomplishing this crimping operation, such as for example the apparatus and techniques disclosed in US. Pat. Nos. ED157545; 3,I55,l37 and 3,423,8l5. The present invention is directed to an improved apparatus and coordinated control arrangement for such a production line crimping operation.

SUMMARY OF THE THE INVENTION The primary object of the invention is to provide an improved production line crimping press for tapecarried workpieces which will cut down operating cycle time and provide coordinated operation of the crimping and feeding mechanisms.

Another object of the invention is to provide such a crimping press with interlocking safety controls which will minimize the possibility of injury to the operator of the press as well as minimizing defective operations resulting from lack of precision in the timing of the coordinated operations of the press.

A particular feature of the invention lies in the structure and control of the ram cylinder which permits both the crimping stroke of the ram and the retraction of the ram to be powered by fluid pressure, while the advance of the ram to work-engaging position is accomplished by spring-loading the ram while the ram cylinder is completely relieved of pressure, so that the initial downward thrust of the ram is slower and with less force than would be the case if it were powered throughout its operating cycle.

Another feature of the invention is in the use in the hydraulic ram cylinder of a floating piston assembly which is mechanically independent of the piston assembly to which the ram is attached. This arrangement permits one part of the piston structure to maintain a desired control-actuating position during the operative cycle while the ram can be mechanically moved to a desired position without affecting the position of the floating piston assembly.

Still another particular feature of the invention resides in the fluid pressure actuation of the hydraulic feed mechanism in which fluid pressure is constantly maintained on the cylinder and the direction of movement of the feeding mechanism piston rod is controlled by relieving pressure on only one side of the piston.

A further special feature of the invention lies in the means for automatic actuation of the operative cycle of the press and the safety controls for preventing inadvertent double hits of the crimping ram which could cause possible injury to an operator as well as mutilation of a workpiece.

Other objects and advantages of the invention will appear more fully hereinafter.

BRIEF DESCRIPTION OF THE DRAWING In the drawings, in which like reference numerals designate like parts throughout the same,

FIG. 1 is a view in side elevation of a crimping press embodying the features of my invention.

FIG. 2 is a view in elevation of the press as seen from the lefthand side of FIG. 1.

FIG. 3 is a view in elevation of the rear of the press as seen from the righthand side of FIG. 1.

FIG. 4 is a fragmentary view in elevation of the crimping press, with portions thereof removed and showing a sectional view of the structure of the hydraulic ram assembly, taken essentially as indicated on line 44 of FIG. 2.

FIG. 5 is an enlarged fragmentary crosssectional view of the feed mechanism taken as indicated on line 5-5 of FIG. 1.

FIG. 6 is an enlarged view in elevation of a portion of the ram assembly showing details of the ramactuated electrical switch.

FIG. 7 is a fragmentary elevational view. similar to FIG. 6, taken essentially as indicated on line 7-7 of FIG. 6.

FIG. 8 is an enlarged fragmentary plan view of the tapemounted workpieces, taken as indicated on line 88 of FIG. 2.

FIG. 9 is a schematic diagram showing a representative form of electrical and pneumatic circuitry for the crimping press.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The crimping press, generally indicated by the reference numeral 10, can be provided with any suitable, sturdy frame structure which, as best seen in FIG. 2, may consist of a base portion 11,

side plates

12 and 13, and a top plate or cross member 14 all suitably assembled and joined to each other to provide a rigid structure.

Secured to the top member 14, as by stay bolts 15, is a hydraulic ram cylinder 16, the interior detail of which is best seen in FIG. 4. The cylinder 16 is provided with two

separate piston assemblies

17 and 18. Each piston assembly may have one or more pistons and a common piston rod. As shown in FIG. 4, the upper piston assembly 17 may have two pistons 19 mounted on a common piston rod 20 which projects beyond the lowermost of the pistons 19. The lower piston assembly 18 is shown, by way of example, as having only one piston 21, although more than one piston could be utilized, and it is mounted on a piston rod 22 which projects from the bottom of the cylinder 16 and to which is secured the crimping ram 23 having mounted on its end the top half 24 of the crimping die. A collar 25 is secured circumferentially of the ram 23 to serve as a seat for a compression coil spring 26 whose other end seats against the bottom of the cylinder 16. It will be noted that the piston assembly 17 is not secured to the ram piston assembly 18 and is mechanically independent thereof. Therefore the spring 26 which normally urges the ram downward into work engaging position, as indicated in FIG. 4, will not cause any corresponding downward movement of the upper floating piston assembly 17 when there is no fluid pressure on the cylinder to cause movement of the piston assembly 17.

Mounted on top of cylinder 16 exteriorly thereof is a retraction sensing valve 27 whose stem or actuating element 28 traverses the upper end 29 of the cylinder 16 so as to be yieldably disposed in the path of upward or retractive movement of the uppermost piston 19. During the operating cycle of the crimping press, when the piston assembly 17 is at or very near its fully retracted position in the cylinder, the displacement of the valve stem 28 causes opening of the valve 27 for a purpose which will be described more fully hereinafter.

Secured to the base 11 of the press is the bottom half 30 of the crimping die which is positioned so as to be aligned with its companion half 24 when the ram is in workpiece-engaging or crimping position. A tapesupport member or block 31 is secured to the press so as to extend transversely behind the ram and the crimping dies and provide a support surface on which the tape band 32 can rest and slide during its indexing movement toward and away from crimping position. A hold-down bar 33 overlies the member 31 in vertical spaced relationship theretoand establishes a vertically restricted path of movement for the tape band 32 so as to prevent the tape band from curling upwardly or lifting off the support member 31 as a result of the feeding of the tape band or as a result of the manipulation of the workpieces or the operations being performed thereon.

As best seen in FIG. 8, the tape band 32 includes a flexible tape 34 which may be made of any one of various synthetic resins suitable for the purpose, and is provided with a longitudinally extending series of uniformly spaced sprocket openings 35 along one marginal edge portion thereof. The opposite edge portion of the tape 34 has mounted thereon a plurality of workpieces W in uniformly spaced relationship to each other, these workpieces being here shown as electrical terminals having barrel portions B of hollow circular cross-section into which a conductor wire or lead C is inserted and crimped in place. The workpieces W can be secured to the tape 34 in any suitable manner, one of such techniques being the use of a second layer of a narrower width of tape 36 which overlies the sand wiched portion of the workpiece W and is spot heatsealed to the underlying tape 34. This arrangement provides pockets in which the ends of the workpiece are retained sufficiently for transport and operative purposes, while still permitting ready detachment of the assembled terminal or workpiece from the tape band at any time after the crimping operation is completed. Although it is not mandatory, it is desirable and certainly simplifies the feeding procedure if the spacing between the workpieces W on the tape band is the same as the spacing between the sprocket openings 35.

Any suitable form of feed mechanism 37 may be utilized for sequentially advancing the tape band 32 properly and accurately through the crimping press. One form of feed mechanism 37 is illustrated in FIG. of the drawings and consists ofa sprocket wheel 38 whose circumferentially spaced projections or fingers 39 are disposed to successively engage the sprocket openings 35 on the tape band and move or advance the tape accurately to bring successive workpieces W into proper crimping position. A ratchet wheel 40 is secured concentrically to the sprocket wheel 38 for movement therewith. A hydraulic or pneumatic feed cylinder 41 has a projecting piston rod 42 having a pawl 43 secured at the free end thereof for reciprocable engagement with the ratchet wheel 40. As the piston rod 42 retracts, the engagement of the pawl with the ratchet wheel causes angular step rotation of the ratchet wheel and the sprocket w-heel until the rod 42 reaches its fully retracted position. When the piston rod 42 is advanced in the opposite direction, the pivotal mounting 44 of the cylinder 41 permits the pawl to ride over the ratchet wheel until it drops into reengagement with the next succeeding ratchet tooth. Each such cycle of reciprocating movement of the piston rod 42 will result in the advance of the tape to bring a succeeding new workpiece into proper index position in the crimping die. A normallyopen electrical switch 45 is secured to the frame of the press and is provided with a switch arm 46 which is disposed in the path of retraction movement of a pin or other abutment 47 which is mounted on the piston rod 42. When the rod 42 has conpleted its tape-feeding movement and is in its fully retracted position, it displaces the switch arm 46 sufficiently to cause closing of the switch. The function of the switch 45 will be more fully described hereinafter.

Another electrical sensing switch 48, which is normally open, is secured to the press and is provided with a switch arm 49 which is displaced by, the collar 25 of the ram to cause closing of the switch 38 when the ram 23 has advanced to workpiece-engaging position in consequence of the biasing effect of the coil spring 26. Another normally open switch 50 is mounted on the press behind the bottom half 30 of the crimping die so as to be aligned with the conductor wire C when it is inserted into the barrel B of the workpiece when the workpiece is in crimping position. This switch 50 may simply consist of an interrupted conductor strip 51 whose gap 52 is bridged by the end of the wire C to close the circuit through the conductor strip. The conductor strip may be suitably secured to a backing plate 53 having an insulation barrier 54 disposed therebetween. The function of both these described

switches

48 and 50 will become apparent as the desciption pro ceeds.

There are two modes of operation of the crimping press, both of which will now be described with particular reference to FIG. 9 of the drawings which schematically illustrates the-electrical and fluid circuitry relating to the operating cycle. It should be noted at this point, that the fluid-powered cylinders and the pressure controls herein referred to are preferably pneumatic, i.e. operated by compressed air, although it is likewise feasible to utilize hydraulic fluid pressure. Inasmuch as the term hydraulic is commonly used to denote fluidpowered devices regardless of whether they relate to the use of compressible or non-compressible fluids, it is to be understood that the term hydraulic as used herein is not intended to be limiting but is intended to embrace both compressible and non-compressible fluids.

When the crimping press is not energized or in operation, the coil spring 26 will cause the ram 23 to be fully advanced or extended in its lowermost positionwhich, assuming that there is a workpiece in the lower die half 30, is the work-engaging position of the ram. If there is no workpiece in the die, the ram will merely abut the lower die half 30 or stop slightly short of that point by reason of the limit of movement of the piston 21 to its lowermost position. This position of the ram is indicated in FIG. 4 of the drawings. A four-way main air valve 55 is connected to the source of compressed air and can be shifted manually to direct the pressurized air to one or the other of two pressure circuits which are shown in FIG. 9. If the valve 55 is shifted to communicate with the circuit 56, the compressed air will communicate directly with a shuttle valve 57, then through an air amplifier 58, controlling three-way valve 59 and pressure circuit 60 to the retract side of the upper and

lower piston assemblies

17 and 18 to cause retraction of the ram 23 in opposition to the spring 26. The operator is now free to manually position and feed the tape band 32 into the crimping press to set up the press for its operation. The raised position of the ram also permits ready and convenient access to the lower portion of the press for the repair, maintenance, adjustment, inspection or replacement of various parts which might be required from time to time. A control knob 61 is conveniently provided on the front of the press for manipulating the main air valve 55 to a position for directing fluid into the circuit 56.

With the tape band now in position, the control knob 61 can be turned to shut off the supply of air through the valve 55, so that the ram will again be returned to its initial position of rest by action of the coil spring 26. If the control knob 61 is further manipulated to shift the valve 55, compressed air will be directed through the pressure circuit 62 to a normally closed foot valve 63 by means of which the operator can manually control actuation of the crimping press.

An electrical on-off toggle switch 64 is provided to control line power to a step-down transformer 65 and to one side of another step-down transformer 66. The secondary of the transformer 65 energizes a low voltage cicuit to a solenoid operated three-way valve 67 which is closed when not energized. The electrical circuit to valve 67 is completed through the normally open ram-sensing switch 48, previously described.

When the foot-operated valve 63 or other manually operable control device is opened, compressed air from the circuit 62 passes through the valve 63 to a shuttle valve 68 to the one-shot air relay valve 69 which transmits a single time pulse of air through the energized solenoid valve 67 which directs it to the three-way valve 70. It will be understood that the solenoid operated valve 67 is only open when the ram is in its work engaging position, as indicated in FIG. 4 which causes the ram switch 48 to close and complete the energizing circuit to the valve 67. The valve 67 will be closed and will block the air flow to the valve 70 if, for any reason, the ram 23 has not attained its switch-closing workengaging positionv Therefore, until such time as the spring 26 has brought the ram to rest upon the workpiece, the three-way valve 70 will not receive the pulse from the one-shot relay valve 69.

The air pulse to the valve 70 shifts its spool and causes the main air pressure to be directed into a header 71 which feeds a relief valve 72, a pressure gauge 73 and the upper or advance end of the ram cylinder 16. The air pulse is relieved when valve 69 automatically resets itself. 7

The pressure on the advance end of cylinder 16 provides the crimping force for the ram 23 which is in engagement with the barrel B of the workpiece, through which the operator has previously inserted the bare conductor wire C. This air-power thrust of the ram completes the crimping assembly of the barrel to the wire as pressure builds up in the cylinder 16 to a preselected or predetermined value which has been empiri cally determined to be sufficient to complete the desired crimping operation. The adjustable relief valve 72 is set to open at this predetermined pressure value to direct the compressed air to resetting of the spool of the valve to shut off the air flow to the header 7] and the advance end of the cylinder 16. The opening of the relief valve 72 also directs air to a three-way valve 74, which is associated with the control of the feed cylinder 41, and causes shifting of its spool to direct mainline air pressure through valve 74 to the retract end of the cylinder 41, which previously was free of pressure. It will be noted that the advance end of the cylinder 41 is continually in communication with mainline air pressure directly through the valve 55 and the circuit 62. Prior to the just-described shift of the valve 74, the piston rod 42 had been in fully contracted position. Due to the lesser area of surface on the piston rod side of the feed cylinder piston, the equal air pressures on opposite sides of the feed cylinder piston are reflected in a differential force in the direction of advancing the piston and piston rod 42 and maintaining the piston rod in the advanced position indicated in FIG. 5 of the drawings. When the pressure on the retract side of the feed cylinder 41 is exhausted through valve 74, the piston rod is under a retract force which, by reason of the feed mechanism illustrated in FIG. 5, causes advance of the tape band 32 to index the next succeeding workpiece W to crimping position while simultaneously transporting the just completed crimped piece away from the crimping die. This described action of the feed mechanism 37 occurs substantially simultaneously with the completion of retraction of the ram 23 which results from the compressed air being directed from the relief valve 72, through shuttle valve 57 and air amplifier 58 to shift the spool of valve 59 and direct the mainline air pressure through the circuit 60 into the retract end of the power cylinder 16. The ram 23 is thus retracted from crimping position, in opposition to the spring 26, at the same time as the valve 74 puts air pressure on the cylinder 41 to advance the piston rod and reset the feeding mechanism. The opening of the relief valve 72 thus accomplishes the shutoff of the pressure advance of the ram, the initiation of the powered retraction of the ram, the cocking of the feed mechanism for the next advance of the tape band and the resetting of the three-way valve 70 to receive the next one-shot pulse from the relay valve 69.

It will be noted that the arrangement of a two part

multiple piston assembly

17 and 18 provided with suitable baffles or partitions 79 and suitably ported as at 80 to provide air to the upper piston assembly only during the down stroke, results in a pressure-force condition in which the retract air on the lower end of the cylinder 16 can be directed solely against the lower piston 21 and the ram advanced pressure directed to the advance end of the cylinder 16 can be multiplied'in force by being directed to the pistons 19 as well as to the piston 21. The retraction of the ram thus may be more gradual and involve a considerably lesser force on the piston assemblies than the crimping advance of the ram. When the ram 23 has reached its fully retracted position, the floating piston assembly 17 engages the stem 28 of the sensing valve 27 to cause it to open. The valve 27 is exposed to main line air from the circuit 62 and feeds a pulse of air through circuit to shift the spool of the three-way valve 74 to exhaust the retract end of the feed cylinder 41 and cause retraction of the piston rod 42 to advance the tape band and the next succeeding workpiece W to the crimping position while at the same time transporting the crimped piece away from the crimping die. It will be understood that the sequence of operation described for the three-way valve 74 in relation to the feed cylinger 41 is intended to cause the feeding mechanism to advance the tape band after the ram has fully retracted and to reset the feeding mechanism for the next advance of the tape band in response to shifting of the spool of the valve 74 in response to opening of the relief valve 72. If the feeding mechanism is such that it would advance the tape band in response to advancing movement of the piston rod 42, rather than as shown in FIG. of the drawings, then it will be apparent that the sequence of operation of the valve 74 would be modified or reversed so as to exhaust the retract end of the cylinder 41 in response to the opening of valve 72 and to feed main line pressure to the retract end of the cylinder 41 in response to opening of the sensing valve 27. Thus, whatever form of feeding mechanism is actuated by the feed cylinder 41, the sequence of operation of the valve 74 is arranged to be such as to cause feeding movement of the piston rod 42 when the ram is fully retracted and resetting of the feeding mechanism as soon as the crimping action of the ram has been completed.

The pulse supplied by the sensing valve 27 also shifts the spool of valve 59 to stop the flow of pressurized air into the lower end of the cylinder 16 and exhaust it to atmosphere. The cylinder 16 is now relieved of all pressure which would cause either advancing movement or retractive movement of the ram 23, so that the coil spring 26 can now mechanically urge the ram back towards work-engaging position. From the time that the retractive movement of the ram commenced, thus disengaging the ram from the switch arm 49, until the time that the spring action returns the ram to work-engaging position and reengagement with arm 49 to close the switch 48, the switch 48 is in its normally open position so that there is no energizing circuit to the three-way solenoid operated valve 67. Inasmuch as this valve is closed when not energized, it will not pass the pulse from the one-shot valve 69 despite attempted closing of the foot valve 63, until the ram has returned and reclosed the circuit through switch 48. Thus there is no powered downward movement of the ram from its retracted position to its work-engaging position during the normal operation of the crimping press. The return of the ram is entirely mechanical and with less velocity and considerably less force than would be the case if its return to work-engaging position were powered. If an operator inadvertedly placed his figer or hand or any foreign object in the path of movement of the springloaded ram, there would be substantially less probability of severe injury or damage than would be the case if the downward thrust of the ram to work-engaging position were powered.

As soon as the ram returns to engagement with the workpiece and with the switch arm 49, the three-way solenoid valve 67 is energized and opened and permits the timed pulse from the one-shot valve 69 to pass to reset the spool of the valve 70 and initiate the previously described cycle of manual operation. It is immaterial whether the foot valve 63 is opened after the ram has returned to work-engaging position or has been opened prior to that point in the sequence of operation, as the described cycle of the crimping press will not be initiated until the switch 48 has been closed to indicate that the ram has seated on the workpiece.

It will also be noted that during the spring-induced downward movement of the ram 23, the floating upper piston assembly 17 which is mechanically independent of the movement of the piston assembly 18, can remain in its fully retracted upper position until forced downwardly by the pressurized air again being directed into the upper end of the cylinder 16 through the valve 70 and the header 71. When the relief valve 72 opens, as previously described, it shifts the spool of the valve 74 to again reintroduce main line pressure into the retract end of the feed cylinder 41 to cause advance of the piston rod 42, thus resetting the feeding mechanism 37 for the next advance of the tape during the time that the powered crimping thrust of the ram is occurring.

The above-described cycle of operation of the crimping press is manually initiated by the operators selective closing of the foot valve 63, usually after the ram 23 has returned to work-engaging position and after the operator has had sufficient time to insert the conductor wire C into the barrel of the next workpiece to be crimped. However, the crimping press cycle also lends itself to automatic operation in which no reliance need be placed upon the manipulation of the foot valve 63 by the operator. For this purpose, an on-off or automatic-manual switch 76 is provided to complete the energizing circuit to the previously described transformer 66. The secondary of the transformer 66 energizes a circuit to a solenoid-operated three-way valve 77 through the normally open sensing switches and previously described.

The feed sensing switch 45 is closed when the feed piston rod 42 has reached the limit of its feed thrust for advancing the tape. This occurs and is maintained after the sensing valve 27 has been opened and until there has been powered crimping thrust of the ram 23 resulting in opening of the relief valve 72 to reset the feed cylinder control valve 74, as previously described. At other times during the operating cycle of the crimping press, the switch 45 is in its normally open position. The wire sensing switch 50 is closed only when properly bridged or engaged by the bare end of the conductor wire C after it has been properly inserted in the barrel B of the workpiece W. This closing of the switch 50 could occur at any time after a new workpiece has been advanced by the feed mechanism to crimping position and before the next succeeding advance of the tape band occurs In practice, the conductor wire C is inserted into the barrel B at the time or shortly after the ram has seated on the workpiece and the conductor wire retains its switch closing position until the crimping operation is completed and the next advance of the tape band occurs. At all other times during the cycle of operation, the switch 50 is open.

The three-way valve 77 is normally closed in the nonenergized mode and serves a function comparable to that of the foot valve 63 in the operating cycle of the crimping press, when the switch 76 is closed to the automatic position. Assuming that the operating cycle of the crimping press has reached the point where the ram 23 has been returned by the spring 26 to work-engaging position on the workpiece and that the opening of the sensing valve 27 has caused the spool of the three-way valve 74 to shift to exhaust the retract end of the feed cylinder 41 to cause retraction of the piston rod 42 to the limit of its tapefeeding position, the switch 45 will be in its closed position. However, the energizing circuit to the solenoid valve 77 is still not completed until the switch 50 is also closed. This is accomplished when the conductor wire C is inserted into the barrel of the workpiece on the crimping die and engages the switch 50 to close it. The energizing circuit to the normally closed valve 77 is now complete and causes the valve to open and direct compressed air from the circuit 62 to the shuttle valve 68 and cause one-shot valve 69 to deliver a timed pulse of air through the energized open valve 67 to the three-way valve 70. The crimping thrust of the ram then occurs in the manner previously described, the relief valve 72 opens at the predetermined pressure value, and the other valves and the feed mechanism are actuated in the sequence and in the manner previously described for manual operation. As soon as the piston rod 42 of the feed cylinder advances to reset the feeding mechanism, the switch 45 opens causing closing of the solenoidoperated valve 77. The purpose of the switch 45 is to prevent an inadvertent second hit of the powered ram 23 before the operating cycle of the crimping press has been fully completed. If the switch 45 were not included in the circuit to the sole noid valve 77, it will be apparent that an intermittent contact of the conductor wire C with the switch 50 causing momentary closing of the solenoid valve 77 would cause oneshot valve 69 to transmit its initiation pulse to the three-way valve 70 for the start of a new operating cycle before the ram 23 will have retracted sufficiently to disengage from the switch 48 and open the energizing circuit to the solenoid valve 67, which could block such a pulse. However, with the switch 45 in the circuit, such a second inadvertent hit out of phase with the desired operating cycle is avoided.

As soon as the operating cycle has caused retraction of the ram 23 and advance of the tape band 32. the switch 45 is again closed and the automatic cycle is initiated as soon as the conductor wire C is inserted into the barrel of the next succeeding workpiece to be crimped. It should be noted that although the wire actuated switch 50 has been described in connection with the automatic cycle of the crimping press, it could also be utilized if desired in series with the switch 48 in the energizing circuit to the solenoid valve 67 and serve the same function in manual operation of the crimping press as it does in the described atuomatic cycle of operation. If the switch 50 is disposed in the energizing circuit to the solenoid valve 67, then it is apparent that the manual cycle of operation of the crimping press would not be initiated by the opening of the foot valve 63 unless the conductor wire C were properly positioned in the barrel of the workpiece so as to close the switch 50.

Although the manual operation of the device has been described with reference to the operation of the foot valve 63, it will be understood that a palm valve or other hand actuated valve 78, can be provided on the press to accomplish the same function as is accomplished by the foot valve 63. A characteristic of oneshot relay valves, such as the valve 69, is that after they have transmitted the timed pulse of air, they will not reset and transmit a second pulse unless the main line pressure directed to the valve 69 is first relieved. Therefore, it is a safety feature of the described form of crimping press, during its manual operation, that the operator must intermittently open and close either the foot switch 63 or some other cycle-initiating valve such as the palm valve 78, in order to recycle the operation of the press. The valve 69 will not reset and will not supply the triggering pulse to the valve 70 if the foot valve 63 is held open continually.

It will also be noted that the sequence of the operative cycle of the press is improved by the two-

part piston assembly

17 and 18, which permits the upper piston assembly 17 to remain in its retracted position, while the lower piston assembly 18 is advanced downwardly in response to the action of the spring 26. During the crimping portion of the operative cycle, when main line air pressure is placed upon the upper end of the cylinder 16 and a multiplication of force is obtained by means of the

multiple pistons

19 and 21, there is an initial gradual movement of the upper piston assembly 17 into gentle abutment with the lower piston assembly 18 in immediate response to the initial low-value build-up of the incoming air in the upper portion of the cylinder 16. This occurs in a matter of milli-seconds. By the time that the air pressure in the cylinder starts building to any significant values, the upper piston assembly 17 is already in engagement with the lower piston assembly 18 so that simultaneous downward displacement of these two piston assemblies occurs during the crimping action. On the other hand, during the powered retraction of the ram, the incoming air at the bottom of the cylinder 16 acts only upon the lower piston 21, as it is isolated from and not ported to the pistons 19, so that the upward retraction movement of the piston assembly 17 follows and is in response to the upward thrust of force of the lower piston assembly 18 only.

It is to be understood that the forms of my invention, herewith shown and described, are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a power-operated crimping press for tapecarried workpieces to be crimped, the combination of a fluid-powered first hydraulic cylinder with a ram for engaging the workpieces and exerting a crimping force thereon, press-actuating means for directing fluid under pressure to said press, first electrically-operated valve means blocking said fluid flow in its nonenergized mode, spring means associated with said ram to yieldably advance said ram toward workpieceengaging position, first electrical switch means for enerizing said first electrically-operated valve means to open position in response to closing of said switch means by movement of said ram to said workpieceengaging position, a second hydraulic cylinder, a feed mechanism for sequentially advancing said tapecarried workpieces to crimping position and powered by said second cylinder, second valve means responsive to opening of said first electrically-operated valve means for controlling pressure fluid to said ram to cause crimping thrust of said ram, third valve means responsive to attainment of a predetermined crimping pressure by said ram for directing fluid pressure to retract said ram in opposition to said spring means and to cause resetting of said feed mechanism, and fourth valve means responsive to retraction of said ram for relieving fluid pressure on said first cylinder and directing fluid pressure to said second cylinder to advance said feed mechanism and index said tape while said spring means is advancing said ram to workpiece-engaging position to complete the operative cycle.

2. A combination as defined in claim 1, wherein said press-actuating means comprises a one-shot fluid pressure valve.

3. A combination as defined in claim 2, including a fifth valve means for directing fluid under pressure to bypass said one-shot valve and into said first cylinder to cause retraction of said ram in opposition to said spring.

4. A combination as defined in claim 1, wherein said first hydraulic cylinder is provided with a plurality of piston assemblies movable independently of each other, each of said piston assemblies including at least one piston and one piston rod, said crimping ram being mounted on one of said piston assemblies and efecting advancing movement thereof in response to said spring means free of any corresponding movement of the other of said piston assemblies from its retracted position, whereby said ram is mechanically advanced to workpiece-engaging position while said other piston assembly maintains retracted operative engagement with said fourth valve means until pressure-displaced.

5. A combination as defined in claim 2, including a fifth electrically-operated valve means blocking fluid flow to said one shot fluid pressure valve in its nonenergized mode, and second electrical switch means for energizing said fifth valve means to open position in response to movement of said feed mechanism to tapeadvanced position, whereby to actuate said press crimping cycle through said one-shot valve.

6. A combination as defied in claim 2, including a fifth electrically-operated valve means blocking fluid flow to said one-shot fluid pressure valve in its nonenergized mode, and second electrical switch means for energizing said fifth valve means to open position in response to engagement thereby of an assembly element of said workpiece when said workpiece is in proper crimping position, whereby to actuate said press-crimping cycle through said one-shot valve.

7. A combination as defined in claim 6, wherein said workpiece is an electrical terminal having a deformable barrel portion adapted to be crimped onto a conductor wire inserted therethrough, said assembly element is said conductor wire, and said second electrical switch means is disposed in the path of movement of said inserted conductor wire to be engaged thereby to circuitclosing position.

8. A combination as defined in claim 7, including third electrical switch means in series with said second electrical switch means and disposed in the path of movement of said feed mechanism to tape-advanced position and engaged thereby to circuit-closing position, whereby intermittent closing contact of said second switch means is ineffective to energize said fifth valve means to open position when said feed mechanism is not proximate its fully tape-advanced position.

9. In a fluid power-operated press for sequentially exerting a work force upon a plurality of workpieces fed to said press, the combination of a fluid pressure operated cylinder, a first piston assembly provided in said cylinder, a work-engaging tool operatively coupled to said first piston assembly for concurrent associated movement therewith, a second piston assembly provided in said cylinder for movable engagement with said first piston assembly, first mechanical force means biasing said first piston assembly and said tool into work-engaging contact independently of any movement of said second piston assembly, second means for directing fluidpressure onto both said first and second piston assemblies to effect sequental displacement thereof to further move said tool into said workpiece and exert a work force of predetermined value thereon, and third means for relieving said cylinder of said firstnamed directed fluid pressure and counter-directing said fluid pressure solely onto said first piston assembly to effect reverse displacement of said piston assemblies and movement of said tool in the opposite direction with a force of substantially lesser value than said work force.

10. A combination as defined in claim 9, wherein said first mechanical force means are energized in response to said reverse displacement of said piston assemblies.

11. A combination as defined in claim 10, including fourth means responsive to said reverse displacement of said piston assemblies for relieving said fluid pressure on said cylinder to permit said mechanical force means to effect said movement of said first piston assembly, while said second piston assembly remains in situ.

12. A combination as defined in claim 11, including fifth means responsive to said reverse displacement of said piston assemblies for feeding a workpiece to toolengaging position.

13. A combination as defined in claim 12, wherein said workpieces are carried on a tape-band for feeding movement to said tool.

14. In a power-operated crimping press for a plurality of tape-carried workpieces to be crimped onto an element inserted thereon, the combination of a reciprocable crimping tool, fluid pressure operated first means for advancing said tool into crimping relationship to said workpiece and element, second means responsive to attainment of a value of fluid pressure sufficient for completion of said crimping for reversing the movement of said first means to retract said tool, third fluid pressure means responsive to retracted position of said tool for feeding said tape to index the next-succeeding workpiece, resilient mechanical fourth means engaging said tool and energized in response to said retraction of said tool for advancing said tool to work-engaging position after said second means becomes inoperative, and fifth means for selectively actuating said first means.

15. A combination as defined in claim 14, including sixth means operatively associated with said first means to complete actuation thereof in response to insertion of said element onto said workpiece.

16. A combination as defined in claim 14, including sixth means operatively associated with said first means to complete actuation thereof in response to advance of said tool to work-engaging position.

17. A combination as defined in claim 14, including sixth means operatively associated with said first means to complete actuation thereof in response to feeding movement of said third means.

18. A combination as defined in claim 17, including seventh means operatively associated with said first means and said sixth means to complete actuation of said first means in response to insertion of said element onto said workpiece.

Claims

1. In a power-operated crimping press for tape-carried workpieces to be crimped, the combination of a fluid-powered first hydraulic cylinder with a ram for engaging the workpieces and exerting a crimping force thereon, press-actuating means for directing fluid under pressure to said press, first electricallyoperated valve means blocking said fluid flow in its nonenergized mode, spring means associated with said ram to yieldably advance said ram toward workpiece-engaging position, first electrical switch means for enerizing said first electrically-operated valve means to open position in response to closing of said switch means by movement of said ram to said workpiece-engaging position, a second hydraulic cylinder, a feed mechanism for sequentially advancing said tape-carried workpieces to crimping position and powered by said second cylinder, second valve means responsive to opening of said first electricallyoperated valve means for controlling pressure fluid to said ram to cause crimping thrust of said ram, third valve means responsive to attainment of a predetermined crimping pressure by said ram for directing fluid pressure to retract said ram in opposition to said spring means and to cause resetting of said feed mechanism, and fourth valve means responsive to retraction of said ram for relieving fluid pressure on said first cylinder and directing fluid pressure to said second cylinder to advance said feed mechanism and index said tape while said spring means is advancing said ram to workpiece-engaging position to complete the operative cycle.

5. A combination as defined in claim 2, including a fifth electrically-operated valve means blocking fluid flow to said one-shot fluid pressure valve in its non-energized mode, and second electrical switch means for energizing said fifth valve means to open position in response to movement of said feed mechanism to tape-advanced position, whereby to actuate said press crimping cycle through said one-shot valve.

6. A combination as defied in claim 2, including a fifth electrically-operated valve means blocking fluid flow to said one-shot fluid pressure valve in its non-energized mode, and second electrical switch means for energizing said fifth valve means to open position in response to engagement thereby of an assembly element of said workpiece when said workpiece is in proper crimping position, whereby to actuate said press-crimping cycle through said one-shot valve.

7. A combination as defined in claim 6, wherein said workpiece is an electrical terminal having a deformable barrel portion adapted to be crimped onto a conductor wire inserted therethrough, said assembly element is said conductor wire, and said second electrical switch means is disposed in the path of movement of said inserted conductor wire to be engaged thereby to circuit-Closing position.

9. In a fluid power-operated press for sequentially exerting a work force upon a plurality of workpieces fed to said press, the combination of a fluid pressure operated cylinder, a first piston assembly provided in said cylinder, a work-engaging tool operatively coupled to said first piston assembly for concurrent associated movement therewith, a second piston assembly provided in said cylinder for movable engagement with said first piston assembly, first mechanical force means biasing said first piston assembly and said tool into work-engaging contact independently of any movement of said second piston assembly, second means for directing fluid pressure onto both said first and second piston assemblies to effect sequental displacement thereof to further move said tool into said workpiece and exert a work force of predetermined value thereon, and third means for relieving said cylinder of said first-named directed fluid pressure and counter-directing said fluid pressure solely onto said first piston assembly to effect reverse displacement of said piston assemblies and movement of said tool in the opposite direction with a force of substantially lesser value than said work force.

12. A combination as defined in claim 11, including fifth means responsive to said reverse displacement of said piston assemblies for feeding a workpiece to tool-engaging position.