US2897703A

US2897703A - Hydraulically actuated crimping tool

Info

Publication number: US2897703A
Application number: US670976A
Authority: US
Inventors: Howard R Fischer; Haem Marcel P D
Original assignee: Chicago Pneumatic Tool Co LLC
Current assignee: Chicago Pneumatic Tool Co LLC
Priority date: 1957-07-10
Filing date: 1957-07-10
Publication date: 1959-08-04
Anticipated expiration: 1976-08-04

Description

Aug. 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING TOOL 7 Sheets-Sheet l Filed July 10, 1957 Aug. 4, 1959 H. R. FISCHER' ETAL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING Toor.

Filed July l0, 1957 7 Sheets-Sheet 2 BY m ATTDRN Aug. 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULICALLY .ACTUATED CRIMPING TOOL '7 Sheets-Sheet I5 Filed July 10, 1957 Aug 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULIC/'ALLY ACTUATED CRIMPING TOOL Filed July 10, 1957 7 Sheets-Sheet 4 ATTRNEY Aug. 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING TOOL Filed July 10. 1957 7 Sheets-Sheet 5 Aug. 4, 1959 H. R. FISCHER ETAL 2,897,703

HYDRAULICALLY AcTuATED CRIMPING TooL.

'7l Sheets-Sheet 6 Filed July 10, 1957 f a l f l g QQ N Aug. 4, 1959 H. R. FlscHER ETAL 2,897,703

HYDRALICALLY ACTUATED CRIMPING TOOL Filed 'July 10, 1957 7 sheets-sheet 7 Tlc'l.

BY WM/5M ATTORN EY 2,897,703 Patented Aug. 4, 1959 HYDRAULECALLY ACTUATED CRMPING TOL Howard R. Fischer and Marcel P. DHaem, Utica, NSY., assignors to Chicago Pneumatic Tool Company, New York, NX., a corporation of New Jersey Application .lilly l0, 1957, Serial No. 670,976

i8 Claims. (Cl. 81-15) This invention pertains to a pneumatically powered compressing tool that is compact in size and is adapted to be held in the palm of the hand when operated. The tool is particularly suited for use in wire terminal crimping operations, and the like.

A general object of the invention is to provide an improved and practical pneumatically operable compressing tool of small size that is held in the hand when operated.

A feature of the invention is a highly efficient mechani cal movement of elements powered by a piston driven wedge, whereby la movable jaw is caused to be compressively closed upon a stationary jaw.

A further feature of the invention is a practical trigger controlled arrangement of valves for effecting pneumatically upon each actuation of the trigger a single reciprocating movement of the piston driven wedge.

Another feature of the invention is a-manually operable push button control arrangement for opening by pneumatically powered means the jaws of the tool to enable insertion of work material between them.

Another feature of the invention is a manually operable latch for safely holding the jaws locked in open position after the push button has been released.

A still further feature of the invention is an interlock safety arrangement, whereby a compressive action of the tool cannot be effected while the jaws are held in open position.

Another object of the invention is to provide a practical hand tool wherein all of the foregoing yfeatures are embodied.

The invention further lies in the particular construction of its various parts, and also in their general arrangement and cooperative association with one another to effect the results intended herein.

The foregoing and other objects, features and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein an embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for purposes of illustration and description, and they are not to be :construed as` delining the limits of the invention.

ln the drawings:

Fig. 1 is a longitudinal section through the tool;

Fig. 2 is a plan section on the line 2-2 of Fig. l;

Fig. 3 is a cross section on the line 3-3 of Fig. 2;

Fig. 4 is a cross section on the line 4-4 of Fig. 2;

Fig. 5 is an enlarged sectional view showing the latch block in a latched condition, holding the jaws of the tool in fully open position;

Fig. 6 is a cross section on the line 6-6 of Fig. 5;

Figs. 7 and 7a are enlarged sectional views which schematically show the condition of the tool preparatory to effecting operation of the tool and a consequent crimping action upon terminal wire elements received between the dies, Fig. 7a showing the valve system in normal position;

open position.

Figs. 8 and 8a are enlarged sectional views which schematically show the condition of the tool upon completion of the forward stroke of the tool in effecting a crimping action;

Fig. 9 is a sectional view which schematically shows the relation of the control and pop-off valves at the end of the return stroke of the wedge and while the `trigger is still held depressed; and

Fig. l0 is an enlarged sectional View which shows the valve system immediately after the trigger has been actuated.

The tool illustrated in the accompanying drawings includes a housing 20 providing a drive or work piston chamber 21 which is closed at its rear by a valve block or head 22. The opposite end of the piston chamber opens through a reduced area 23 into a forward chamber 24. The latter opens out through the bottom and front end of the housing. Disposed within chamber 24 in parallel spaced relation to each other is a pair of side bearing plates 25, 25'. These plates, as appears in Figs. 2 and 3, project in part through the front end and through the bottom of the housing. An upstanding arm 26 of a yoke member 27 is rigidly retained between the forwardly projecting portions o-f the side plates by means of pins 28. The inner walls of the side plates serve as bearing faces for a tail end or block portion 29 of a ram 31. The latter has a reduced cylindrical shaft 32 which continues forwardly from the ram block 29 and slides through a complementary opening in the yoke arm 26. A ram jaw 33 has a tail piece 34 retained in an end bore of ram shaft 32 by a suitable pin. Jaw 33 represents the movable member of a pair of opposed jaws. The other jaw 35 is stationary, and is an integral part of the yoke member.

Jaws

33 and 35 are adapted to accommodate separate halves of a pair of wire terminal crimping dies 36, 37 (Fig. l). The particular dies shown are for purposes of illustration only. The dies serve, when closed under pressure, to effect a crimping action on wire terminal elements 38 disposed between them (Figs. 7 and 8).

The movable jaw 33 is normally held in its forward or closed position (Fig. l) by a spring loaded holding piston 39. The latter is pneumatically operable to move against this spring load so as to draw the ram jaw to This piston moves in a cylinder 41 formed by the housing in the upper area of chamber 24. An open rear end of this cylinder is closed over by a washer plate 42. which abuts against a suitable snap ring retained in an internal groove of the cylinder. The piston carries a rod y43 which is slidable through the washer plate into the upper rear area of chamber 24. The free end of an upstanding piece 44 of a draw bar 45 is retained at 46 upon an externally projecting end of the piston rod. The draw bar slides in a channel track 47 formed in the underside of the piston cylinder. Integral with the forward end of the draw bar is a fork having a pair of depending ngers 48. The latter depend freely into a pair of vertical slots 49 formed on opposed inner faces of the arms 51 of a bifurcation `formed in the rear of the nam block 29. Coil spring means 52 disposed about the piston rod 43 and loaded between the piston and the washer plate constantly unges the piston to a normal forward position (Fig. l), wherein the lingers 48 of the draw bar hold the movable jaw in its forward or closed position.

Pneumatic control means (Figs. 1, 2, 4, 5, 7, 7a) is provided to actuate the holding piston 39 to cause the movable jaw 33 to be drawn to its open position. To this end, the valve block 22 has a supply inlet 53 which is adapted for connection by a hose line, not shown, to a source of pressure air. A branch passage 54 from this inlet leads through the valve block and housing to a chamber 55 of a check valve 56. The latter is continuously under the load of pressure air in passage 54, andrnormally seals chamber 554 offA from a passage 57. The latter. passagej communicates. by radial port 58 throughthechamber 59 ofA an interlockslide member 6l with afurther passage 62 leading to the chamber of.

cylinder 41ahead of the holding-piston. The check valve has astem 63which extends freely through pas.- sage57 into an enlarged counterhore 64.that opens to the'outside of the housing. Threaded on the end of this, stem is a push button 65 that projects inpart from thehousing, and has a loose tincounterbore 64.y The check valve is unseated by manually depressing the push..

bullion.A While the checkvalveisunseated, pressure air owsfthrough the associated passages to the holding piston 39,. after. slidingthe interlockvalve y61 .tothe left against the load of a light spring V,66, whereupon 'the'hold-U ing'pistonis forced tothe right against theloadof its springs 52, and the drawbar 45 `is caused to draw-by means of its fingers 48..the movable jaw 3310 its fully open position, as appears in. Fig. 5.- WhileY the push button is manually helddepressed, an O-ring 67 on the inner end of the latter seats upon a shoulder 68 and prevents escape of pressure air around the outer diameter of the push button.

After push button 65 is manually released andthe check valve thus reseated, jaw 33 is returned toits normally closed position by the holding pistonl as the latter restores under the load of spring means 52. As piston 39 restores, air in the piston chamber ahead of the Vpiston vents.to atmosphere around the outer diameter of the push button.

The primary function of the pneumatically operable holding piston is to permit

jaws

33 and 35 to be drawn apart so as to enable insertion of uncrimped wire terminal elements 38 between the dies 36, 37. After the latter-action is effected and the push button is released, theholding piston under the load of its springs carries the die 36 of the movable jaw into abutment with the terminal wire elements 38 and thereby holds the-latter in place (as in Fig. 7). Pneumatically poweredmeans is provided to next pressurize the jaws and dies so as to etect a crimping action upon the wire terminal elements.

This pneumatically powered pressurizing means includes a lever bar 69 having a slightly rounded nose 71 at its forward end. This nose extends into the bifurcation formed inthe rear of the ram block 29 and it abuts against. the back wall 72 of the bifurcation. The nose endof the lever is loaded into abutment Withwall 72 of the ram block serve to anchor the springs at the opposite end. A cross shaft 76 projects through opposite sides of.the.rear portion of the lever. Each projecting end of -this shaft is iitted with bearings carrying a roller 77. An-eccentric cam face 78, forming the rear end of the lever, is normally in close proximity to the peripheral surfaceof a large roller 79 which hasa stationary position relative to the housing.

Roller 79v is carried by bearings fitted on a stationary cross shaft 81. The vends of this shaft are supported in complementary holes formed in opposed bossed portions Y 82 Lof thesideplates 25, 25. The side plates and cross shaft 81 are retained in the housing by headed bushings 83 ttedin opposite sides of the housing and by bolts 84 threaded through the vbushings into opposite ends of the cross shaft'.

When the movablev jaw 33 isdrawn to open position (Fig. 5) by the holding piston as previously described, the eccentric eam-end 78' of the lever is caused to ride down-overthe large roller as the oppostite'nose end 7l of the lever pivots against the back wall 72 of the bifurcation of the ram block. The underside of the lever is limited in its downward movement by a stub roll pin supported in the side plate 25. An underlip S5 formed at the forward end of the lever, and an upper lip extension 86 of a spring plate mounted on the latter, respectively extend under and over the ram block 29, whereby the lever is guided in a vertical plane during its pivoted movement.

lf it is desired that

jaws

33, 35 remain open for any length of time, locking means is provided to' lock them in this open position, so as to avoid the necessity of continuously holding the push button 65 depressed. This locking means comprises (Figs. l, 5, 6) a latch block 87 which is arranged below ram block 29. This latch block is vertically slidable between the

side plates

25, 25. It is guided in this sliding movement by the rear end wall SS-of the yoke arm 26 and by a-pair of stub roll pins 89 carried by the sideplate 25.'v When'the ram member is drawn to its fully open position, the tail blockr 29 thereof is drawn clear of the latch block 87'and the cylindrical shaft 32 of the ram member is moved to a position above the latch block. A semi-circular trough 91 in the latter is adapted to engage about the `ram shaft in front of a shoulder 92 of the ram block, when the latch block is moved upwards. Shoulder 92 abuts against the latch block in this moved position ofthe latter, whereby the ram member is held inits moved or fully open position.

A manually operated cam lever 93 is arranged to effect up or down movement of the latch yblock and consequent engagement or disengagement of the latter with the ram member. This lever is substantially triangular and is pivoted at its vertex on a cross pin 94 supported in the housing. A nosed corner ofthis lever extends into an under-bifurcation 95 of the latch block and is pivotedl therein on a pin 96 supported by the arms of the bifur cation. A linger 97 projecting from the lever to the outside of the housing enables manipulation of the lever,

whereby the latch block may be vertically'raisedor lowered relative to the ram-shaft. The latch block retains its moved position by friction means provided by a pair of ball elements 98. These are spring -loaded outwardly of the latch block so as to frictionally engage opposed faces of the side plates25, 25.

After-the latch block is disengaged fronrthe ram shaft, the movable ram jaw 33 will be automatically returned by'the springrloaded holding piston39to normal position. As the ram jaw Vrestores,lthe `lever barV 69 will be caused to pivot in a vertical plane to its normal hori Zontal position, as in Fig. l, being aided iu this respect by the side springs r'73. ln the cvent of an abnormal overrise of lever 69 aboveits horizontal position, the upper rear area thereof will strike the undersideiof the closely overhanging draw bar 45. l'n thisaction the spring lip 86 will be forced down upon thetail block and will yield slightly, whereby damage to theflever, that might .otherwise occur if this upper lip were rigid,l is avoided.

If wire terminal elements :5S-have been previously disposed between the dies for a crimping action, the mov.

This wedge has a normal positioirlas in Fig. l, between the piston chamber 2i and the forward chamber 24. An axially extending tail shank lill of the-wedge is retained by a suitable pin in a forked member 102.. The forked member has an axial extensionV which is retained by a threaded portion and nut means 10S-to a driveV or work piston v1041.-.

The latter reciprocates in piston` chamber n 21. Lengthwivse of the underside of the wedge is a chan bearings.

nel track 165 in which is slidably received an upper portion of an elongated thick center rail 106 of a ladder roller cage 167. This center rail or bar carries transversely thereof a succession of pin type rollers 169 which, with the exception of at least the rst one S, are needle The ends of the several rollers project from opposite sides of the center bar about midway of the upper and lower surfaces of the latter, whereby an upper rail portion and a lower rail portion are provided (Figs. 3, 4). The lower portion is adapted to ride in an underchannel track r11 formed lengthwise of a tlat surface of an upper portion of a trigger supporting piece 112 of the tool.

The latter piece or section is assembled between the lower portions of the

side plates

25, 25. To this end, the side plates provide a pair' of opposed shoulders 113 (Figs. 3, 4) lengthwise of their inner faces. A narrow underportion 114 of section 112` depends between these shoulders and projects between the bottoms of

plates

25, 25 to the outside of the housing. The upper portion of the trigger supporting section provides longitudinal shoulders 115 iwhich overlie the shoulders 113 of the side plates. The projecting ends of the rollers of the roller cage are adapted to roll upon the shoulders 115 as` the center rail 136 of the cage moves in the trackway 111. Depending legs 116 of the wedge freely straddle the center rail 1416 and are adapted to ride over the rollers of the roller cage as the wedge moves.

As the wedge is driven forwardly by the work piston 104., it rapidly and smoothly rides over the needle bearings of the roller cage to engage and to pivot the ram lever 69 upward. In this movement of the wedge relative to lever 69, the side rollers 77, which hang in part below the under-edge of the lever are engaged by a cam varying upper surface 117 of the moving wedge. A slot 118 in the nose of the wedge is provided to avoid intert ference ywith a projecting lower corner 119 of the lever,

so that the latter corner will not strike the wedge. As the rising cam surface of the rapidly moving wedge moves against and under the rollers 77, it pivots the ram lever 69 upwards and forces the eccentric earn end of the lever over the surface of the large roller 79. In this action, lever 69 straightens out to its horizontal position, whereby a strong compressive force is transmitted through the ram jaws and dies to effect a crimping action upon the Wire terminal elements 38, as appears in Fig. 8.

rl`he rst member 1113 of the roller elements of the roller cage is intended to provide a slight frictional drag on the cage so as to enable a rapid movement of the wedge over the needle bearings and a consequent rolling rather than a skidding movement of the cage over the shoulders 115. Due to the friction roller 1618, the cage moves relatively slower than the wedge, so that the Wedge is fully supported along its underside when it applies a final strong lifting force to lever 69. The friction roller 108 comprises (Fig. 4) a pair of pin elements slidably disposed in opposite ends of a cross bore of the center rail 106, and an intermediate spring which presses the pins outwardly so as to frictionally engage the ends of the pins with the

side plates

25, 25. An upstanding lug 121 formed at the rear of the center rail of the roller cage extends into a vertically deeper end portion of the under track 105 of the wedge. rl`he resultant shoulder 122 formed in the underside of the wedge is adapted to engage this lug on a return movement of the wedge and thus carry the roller cage back to normal position. ln the latter action, an opstanding lug 123 (Fig. 8) at the rear of a side shoulder ,t 1. will prevent the roller cage from overriding its normal position.

The work piston 104 that drives the wedge is pneumatically powered, and is reciprocated in response to pneumatic uid caused to How by a trigger controlled arrangement of valves (Figs. l, 2, 7, 7a, 8a, 9, 10).

Operating pressure air is supplied to the valve block 22 by a hose line, not shown, connected to the inlet 53 (Figs. 2, 7a). A pressure air distributor valve 124 is slidable in a chamber formed by a bushing 125 fitted in an open ended bore of the valve block. The opposed ends of the bore are sealed over in suitable manner by the elements 126 and 127. Valve 124 has a reduced central portion 123 which extends freely through a central neck passage 129 of the valve chamber. A conical shoulder 131 at one end of the reduced valve portion normally seats over an opposed O-ring so as to seal an annular supply inlet channel 132 from the neck passage 129 and from radial ports 133 that lead out of the neck passage to a passage 134 communicating with the work piston chamber 21. When the conical shoulder 131 is seated, an O-ring 135 mounted in a shoulder at the opposite end of the reduced portion 128 of the valve is unseated from the opposite end of the neck passage 129, whereby the latter passage is vented by a port 136 to atmosphere. When valve 124 is in its opposite position, as in Fig. 10, the O-ring 135 is seated so as to close the neck passage 129 olf from the vent, and the conical shoulder 131 is unseated so as to communicate passage 129 with the supply inlet 53.

After turning a supply valve on, not shown, in the hose line connected to the inlet 53, the tool is conditioned, as in Figs. 7 and 7a, for operation. Pressure air thereupon ilows through the inlet 53 into the branch passage 54 leading directly to the chamber 55 of the check valve 56, the function of which was earlier described. Branch passage 54 also connects directly by a lateral line 137 to the forward ends of the chambers 138 of a pair of return pistons 139 (Figs. 2 and 7). The latter have elongated stems 141 which pass through the main piston chamber and are anchored at their ends 142 in diametrically opposed portions of the work piston. The chambers 138 of the return pistons are formed forwardly of the work piston chamber in the wall of the housing of the tool. The total of the effective areas of the return pistons is relatively less than that of the work piston.

Pressure air admitted to the inlet 53 also ows (Fig. 7a) into the annular channel 132. From the latter it enters a radial port 143 to a central passage 144 in the valve, and then passes out at the lower end of the latter through a radial port to the lower end 146 of the valve chamber, just above the inner area of an enlarged endhead 147 of the valve; whereby the conical shoulder 131 of the valve is held seated over the neck passage 129, and the 0ring 135 is held unseated from the opposite end of this passage so that the latter is open to vent 136. The radial port 133 leading from passage 129 into the work piston chamber 21 is also vented in this normal condition of the distributor valve.

A branch passage 148 leading oi the annular channel 132 connects with a chamber 149 of a throttle valve 151. The latter is normally seated over an O-ring so as to seal chamber 149 ott from a passage 152. A reduced stern portion of the throttle valve extends freely through the latter passage to the outside of the valve block. A retainer 154 xed on the right end of this valve stem carries an O-ring which is normally unseated from the adjacent open end of passage 152, whereby the latter is normally vented to atmosphere. Fitted to the tail end of the throttle valve is an arm 156 of a slide member 157 which is slidable in a counterbore 158 of the valve block. This counterbore is a continuation of a Slightly narrower elongated bore 159. The latter extends through the bottom wall area of the housing and opens (Fig. 7) out into a radial recess 161 at the underside of the housing. An elongated draw rod 162 eX- tends slidably through both bores 153, 159 and through the slide member 157. A threaded end portion of the draw rod projects in part to the outside of the slide body and carries an adjustable retaining nut 163 threaded into abutment with the slide member. A coil spring 164 compressed in the counterbore between a shoulder of 'the Vlatter andan fopposed endof the slide member constantly urges the draw rod 162 rearwardly, whereby the throttle valve 151 is normally held seated. The pres'- sure of this coil spring 'upon the throttle valve is adjustable by tightening or loosening the retaining nut 163.

A hooked free end 165 of the draw rod extends into the recess 161 of the housing and is attached to a hooked' 'trigger 171.V The latter pivots at 1724 in the bifurcation 168.

It is clear that a counterclockwise.movement of the trigger 171 (Fig. 8) will act to press the throttle valve forwardly, as in Fig. l0, whereby the Olringfon retainer 154 will be seated to close passage 152011 from vent, and the throttle valve 151 will be unseated to communicate the air supply chamber 149 to passage 152. Following this action, pressure air supplied over passage 148 to chamber 149 will enter passage 152 vfrom where it will flow over a branch 173 in the valve block to the distributor valve chamber immediately below-the underside 174 of an enlarged head end 175 of the distributor valve. The area of the underside 174 of thishead end is relatively greater than the inner area 146 of the opposite head end 147, so that the greater pneumatic pressure acting on the area 174 shifts the distribution valve from its normal position to its opposite position as in Fig.l 10. This shift unseats the conical shoulder 131 and seats the O-ring 135, whereby the neck passage 129 is open to the pneumatic supply line 53 at one end and is closed at its opposite end from vent 136.

Pressure air now enters through

passages

129, 132, 133, 134 to the work piston chamber 21 to drive the pistonand the associated wedge forwardly to effect a crimping action, as earlier described. In thisY forward movement of the work piston, the return pistons 139 are ca rried forwardly in their chambers 138. Any air trapped in the latter will be forced by this'action to flow back over passage 54 to the inlet 53. When the work pistonvhas completed its forward stroke (as in Figs. 8, 8a), air pressure builds up in chamber 21 at the rear of the work piston and also in a connected small antechamber 176 of the valve block. The latter chamber is normally sealed at one end by a pop-off valve 177 (Fig. 7a). The latter works in a relatively larger control valve chamber 178 of the valve block and is loaded by a compression spring 179 to normally seat an O-ring retainer 190 over the open end of the ante-chamber 176. The opposite end of the compression spring sleeves over a spring guide 181 and abuts a shoulder at the end of the latter. A set screw 182 threaded through a cap plug 183 engages the spring guide and serves to adjust the pressure of spring 179 against the pop-off lvalve so as to predetermine the build-up pressure required in the work piston chamber to unseat the pop-ol valve. The compression spring 179 projects through opposite open ends of a control slide valve 184. The latter is slidable rearwardly of the pop-olf valve in the control valve chamber 178.

The control valve has a peripheral channel 185 which normally registerswith a passage 186 connected with the branch 173 leading from the throttle valve. An O- ring retainer 187 xed upon the control valve carries an O-ring which normally seats upon a shoulder 180 formed by a rear enlargement 188 of the control valve chamber. A compression spring 189 disposed between this O-ring retainer and the -inner wall of the cap plug 183 normally holds the O-ring seated on this shoulder, whereby pressure air in passage.186 is prevented from pass ing by way of channel 185 through the control valve 8 t chamber to a passage 191 that leads to the top end 192 of the distribution'valve chamber.

(Figs. 8, 8a.) As air pressure builds up in the work piston chamber, upon completion of the work stroke of the work piston 104,' it reaches a degree at which the pop-off valve 177 unseats. The pressure air then ows into the control valve chamber ahead of the pop-of valve and acts upon the relatively large O-ring retainer 190 of the pop-olf valve, which retainer previously was disposed behind the shoulder 193. The pop-off valve accordingly is forced back against the `load of spring 179 into abutment with the control valve 184, and shifts the latter rearwardly. This unseats the O-ring retainer 187 from the shoulder 180, whereupon channel 185 is caused to communicate passage 186 through the enlargement 188 of the control valve chamber with passage 191. Pressure air thereupon flows to the top end 192 of the distribution valve chamber, and causes the distribution valve 124 to shift in the opposite direction back to normal position, whereupon the supply passage 53 is again closed to the work piston chamber 21 and the latter is again opened to vent 136.' Since the pressure air in the cham bers 138 of the returnpistons 139 is at all times at line pressure, the latter are caused to restore and return the work piston following the return of the distribution valve to normal position.

As the work piston restores, the air trapped at its rear vents through

passages

134, 129, 136. The pop-oil? valve 177 next restores, as in Fig. 9, under the load of its spring as the air pressure in chamber 21 relaxes, but the control valve 184 is unable at this time to restore under the load of a spring 189 because the pressure of air in the enlarged portion 188 of the control valve chamber now acting against the relatively large O-ring retainer 187 is relatively stronger than the opposing force of spring 189 at this time. However, after the trigger 1,71 is manually released, the throttle' valve 151 is reseated by'its spring 164 to normal, as in Fig. 7a, whereupon air trapped in

passages

186, 173 flows around the stem of the throttle valve 151 to vent, whereupon the control valve restores.

Air trapped in the head end 192 of the distribution valve chamber and in the connected passage 191 leaks around the outer diameter of the O-ring retainer 187 to the space at the rear thereof from where it escapes through vent holes 195 in the cap plug.

An interlock feature (Figs. 3 and 7) associates the trigger 171 with the operation of the check valve 56, so that the trigger may not be actuated while the push button 65 'of the check valve is depressed and the check valve is allowing flow of pressure air to the holding piston 39./ This is'a safety measure to prevent an accidental compressive movement of the wedge 99 while the

jaws

33, 35 are temporarily held open by the depressed condition of the push button 65. To this end, the port 58 from the check valve passage 57 leads to the chamber 59 in which the slide member 61 works. The light compression spring 66 within the latter chamber holds this slide member in a position at the right so as to uncover the open end of a vertical bore 197 which runs down through the wall of the housing to the outside. An interlock rod 198 hooked at its bottom end in a cross hole 199 of the trigger, ex; tendsupwardly into this bore. When the trigger-is-in its released condition, the upper end of the interlock rod is just below chamber 59, as in Fig. 3. Now, when the trigger is actuated, the rod will obviously be moved up into chamber 59. If, however, the push button 65 has been depressed and is held depressed, pressure air will' enter the chamber 59 and will force the interlock slide member 61 to cover over the open end of the bore 197. While the latter condition exists, it is obvious that the trigger mechanism cannot be actuated since the interlock rod will lbe blocked by the slide member 61 from moving upward. When the push button is released,

pressure air trapped in the passage 62 leaks around the beveled nose of the slide member 61 and around the outer diameter of the push button to vent.

While an embodiment of the invention has been illustrated and described above, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled `in the art, and it is our intent, therefore, to claim the invention not only as shown and described but also in all such forms and modications thereof as may be reasonably construed to be within the spirit of the invention and the scope of the appended claims.

What is claimed is:

l. in a hand tool of the character described including a housing, a yoke member affixed to one end of the housing and having a stationary jaw, and a movable javt member closable upon the stationary jaw; a piston cham ber formed in the housing, a holding piston movable in the latter chamber, in parallel relation to the movable jaw, an arm connecting the piston with the movable jaw member for movement of the latter upon movement of the piston, a spring load normally loading the piston in a particular direction wherein the movable jaw member is held moved to a position closed upon the stationary jaw, and control means for controlling admission of pressure air to the piston chamber to drive the piston in the opposite direction against the spring load so as to move the movable jaw member to open position.'

2. In a hand tool as in claim l, wherein the control means comprises a pressure air supply line to the piston chamber, and a push button operable check valve in the supply line having a normally closed position.

3. In a hand tool as in claim l, wherein the movable jaw member is characterized by a tail portion having a shoulder at the end thereof, and wherein a latch block is slidable in the housing at right angles to the jaw member and when the jaw member is moved to open position the latch block is adapted to engage with the tail portion in front of the shoulder so as to restrain the movable jaw member against movement to closed position, and wherein manually operable lever means is associated with the latch block for actuating the latter to and from engage.- ment with the said shank portion.

4. In a hand tool as in claim 2, wherein the stationary jaw and movable jaw member have die elements adapted to receive therebetween work material subsequent to movement of the movable jaw member to open position, a power driven wedge is slidable in the housing, and means is provided in the housing for engagement by the driven wedge for transmitting a power movement of the wedge -to the movable jaw member so as to compressively close the latter upon the work material.

5. In a hand tool in claim 4, wherein the wedge is powered by a piston, valve means control a flow of pneumatic fluid to drive the piston, and a manually operable trigger is arranged for actuating the valve means.

6. In a hand tool as in claim 5, wherein interlock means is arranged to prevent operation of the trigger while the push button is in actuated condition, and comprises an interlock chamber 'in the housing, a member slidable in the latter chamber, a rod connected at one end to the trigger and normally slidable at the opposite end into a hole of the interlock chamber upon slight actuation of the trigger, spring means normally holding the slidable member clear of the hole, and passage means to the interlock chamber connectable with the pressure air supply line upon actuation of the push button, whereby the pressure air admitted to the interlock chamber is adapted to move the slidable member to a position over the hole to block entry of the rod into the latter.

7. ln the combination of a housing, a ram member slidable in the housing in a longitudinal direction, a power driven wedge movable in the housing in a longitudinal direction, and means for translating a longitudinal forward movement of the wedge into a corresponding movement of the ram member, wherein the translating means comprises a roller bearing member, a stationary support for the latter, a lever between the rear end of the ram member and the bearing member, means associating the lever at one end for pivot movement relative to the ram member, spring means normally supporting the lever to the ram member in a horizontal plane wherein the longitudinal axis of the lever is `aligned with that of the ram member, and a cam surface defining the opposite end of the lever, the lever being adapted to move rearwardly with the ram member upon a rearward movement of the latter whereby the cam surface is caused to abut and ride downwardly over the bearing member and cause the lever to pivot downward as it does so, and the lever being adapted to pivot upwards to its horizontal position upon a forward movement of the wedge against the underside thereof whereby the cam end of the lever is caused to ride upwardly over the surface of the bearing member and the ram member is caused to move forwardly as the cam end of the lever so rides.

8. In the combination as in claim 7, wherein the means associating the lever with the ram member for pivot movement comprises a rounded nose at the forward end of the lever abutting the rear of the ram member, a spring plate mounted latop the lever yand having a lip extension overlying the ram member, and an under lip extension of the lever underlying the ram member, the upper and lower lips serving to prevent the lever from slipping free of the ram member in a vertical plane.

9. In the combination as in claim 8, wherein an abutment of the housing overlies the lever, being in close proximity to the lever when the latter is in a horizontal plane, the lever being adapted to strike this abutment in the event of an abnormal overrise thereof above its horizontal plane, and the lip extension of the spring plate adapted to resiliently react against the surface of the ram member in the event of such overrise action of the lever.

l0. In the combination as in claim 7, wherein the lever is characterized by depending roller means engageable by the wedge in the forward sliding movement of the latter.

11. In a crimping tool including an elongated housing having a piston chamber and a thickened wall area forwardly of the latter, the wall area having elongated bores therein parallel to the piston chamber, a work piston movable in the piston chamber, and a pair of elongated rods parallel to the longitudinal axis of the work piston and fixed at one end to diametrically opposite portions of the forward face of the latter piston; a pair of return pistons formed at the opposite ends of the rods and adapted to move in the said bores in the said wall area, a pressure air inlet to the housing, a first branch passage from the inlet leading directly to the said bores for continuously conducting pressure air from the inlet to drive the return pistons in a rearward direction relative to the housing, a second branch passage from the inlet for conducting pressure air to the piston chamber to drive the work piston forwardly, the return pistons having a total diameter relatively less than that of the work piston whereby pressure air from the inlet conducted simultaneously to both the return pistons and the work piston will drive the latter forwardly, pressure air flow control valve means associated with the second branch passage for controlling a flow of pressure air from the inlet to the piston chamber so as to cause the work piston to move in a forward direction, manually operable means for actuating the said valve means, and other valve means responsive to a predetermined pressure in the piston chamber at the end of the forward stroke of the work piston for automatically shutting off the flow of pressure air from the second branch passage to the piston chamber and communicating the piston chamber with vent.

12. In' the combination comprising' a housing, a ram` member slidable therein, a wedge'element slidable forwardly and rearwardly in the housing, means disp'c'xsed` ber, and means providing roller support to the wedge;i element in' its sliding movement; wherein thef latter means comprises a trackway formed in the housingbelow the path of movement of the wedge, a'pair" of shoulders'bordering the trackway, and a ladder roller cage" having a thick center guide rail movable" in the trackway and having a series of roller pins' projecting from opposite sides of the rail adapted to roll upon" the shoulders, and the wedge element having'y a pair of 'depending longitudinal shoulders contacting the`roller pins and adapted to ride upon the latter as the'wedgc moves.

13. In the combination as in claim 12, whereinthe ladder roller cage has a normal position relative to the trackway and reacts to the sliding movement of'the wedge to follow in the direction of the latter, wherein the ladder roller cage has an upstanding ear at its rear, and the wedge has an under shoulder engageable with this`ear upon a rearward movement of the wedge, where by this engagement the ladder cage is adapted to be returned to its normal position. p

14. In the combination as in claim 13, wherein the ladder roller cage is longer than the longitudinal shoulders ofthe wedge, a forward portion of these shoulders normally rests upon the roller pins and a rear portion overhangs the rear end of the ladder roller cage, and means is provided to cause the ladder roller cage to move relatively slower than the wedge in reaction to the movement of the latter whereby the longitudinal shoulders`of'the wedge are progressively caused to'fully ride upon the roller pins of the ladder cage. p

l5. In a pneumatically powered tool including a Work piston, a plurality of return pistons attached to the Work piston for movement together with the work piston'and having a total effective area relatively less than that of the work piston, a housing providing chambers for the work piston and the return pistons and having a valve block and a pressure air inlet to the valveblock common to the chambers of the work piston and of the return'pistons; valve means actuable for admitting pressure air from the inlet to the chamber of the Work piston to drive the work piston on a power stroke andV normally blocking such admission of pressure air,'manV ually operated means for actuating the valve means-to admit such pressure air to the work piston chamber,

and other means responsive to a predeterminedvalueV of pressure air in the work piston chamber atter'com'- pletion of the power stroke of the work piston to render the'valve means ineffective to supply further pressure air to the work piston, whereby pressure air'from the' common inlet to the return pistons is effective to operate the latter to return the work piston.

16. In a pneumatically powered tool includinga Work piston, and a pair of return pistons attached to the Work piston for movement together with the latter and hav' ing a total effective area relatively less than that of i the work piston; a common source of pressure air connectedvto both the work piston and the return pistons,V

pressure air to the return pistons whereby the return pistons yare driven to return the work piston, manually operable means for placing lthe control means in its rst condition, and means responsive to a predetermined degree'of pressure arising at the rear of the work piston after completion of the Work stroke of the work piston to place thecontrol means in its second condition.

17. In a'pneumaiically powered tool including a work Vpistorreliecti'veupon a power stroke to actuate one element relative to another, a pair of return pistons attached to the work piston for movement together with the latter and having an effective area relatively less than that of the work piston, a housing providing separate piston chambers for the work piston and the return pistons, a valve block at one end of the housing, a pressure air inlet to the block being common to the chambers of' the work piston and of the return pistons, control' means normally stopping low of pressure air from the inlet to the chamber of the work piston and not to the chambers of the return pistons, manually operable means associated with the control means to actuate the latter to discontinue the stoppage of iiow of pressure air to the chamber of the work piston whereby the differential in pressures of air acting on both the return pistons and the work piston causes the Work piston to execute a power stroke carrying the return pistons with it, and other means automatically responsive to a predetermined development of pressure in the work piston chamber after completion of the said power stroke to actuate the control means to again stop ow of pressure air to the chamber of the work piston and not to the return pistons'whereby the return pistons are caused to move in the opposite direction and to carry the work piston with them.

18.' Inthe combination of a to'ol of the character described including a pneumatically powered work piston movable in a piston chamber, and a source of pressure air; a systm'of interacting slide valves interposed between'thesource and the piston chamber, comprising meansnormally applying pressure air from the source to the'valve system whereby the latter is maintained in a normal condition blocking ow of pressure air from the source to the piston chamber, manually operable means connected to the valve'system effective in an operated condition to vary the directional application of pressure air from the source vto the valve system whereby the latter is caused to be shifted to a second condition allowing ow of pressurel air from the source to the piston chamber to drive the piston over a power stroke, means responsive to a predetermined build-up of air pressure in the piston chamber subsequent to the power stroke of the piston to vary the directional application of pressure air from the source to the valve system so as to shift thel latter to a third condition wherein the valve system discontinues ow of pressure air from the source to the piston chamber, and other means effective upon manual release of the manually operated means to' causeV a directional variation of the application of pressure air from 'the source to the valve system to restorethe latter to its normal condition.

References Cited in the lile of this patent UNITED STATES PATENTS 2,158,855 Eby et al. May 16, 1939 2,254,613 Matthysse Sept. 2, 1941 2,600,860 Dupre lune 17, 1952 2,633,161 Schultz et al. Mar. 31, 1953 2,693,218 Freedom Nov. 2, 1954 2,722,859 Stoltz Nov. 8, 1955