US3672193A

US3672193A - Presser tool with faulty operation lock

Info

Publication number: US3672193A
Application number: US33183A
Authority: US
Inventors: Teddy M Schiller
Original assignee: Purex Corp
Current assignee: AIRWORK Corp A CORP OF DELAWARE; Tp Industrial Inc
Priority date: 1970-04-30
Filing date: 1970-04-30
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A crimping tool employing a fluid pressure operated reciprocable ram. Ratchet means is provided to prevent faulty crimping operations including a ratchet tooth movable with the ram and a pawl adapted to engage the tooth against return movement of the ram in response to a crimping stroke of less than a predetermined length.

Description

United States Patent Schiller [54] PRESSER TOOL WITH FAULTY OPERATION LOCK [72] inventor: Teddy M. Schiller, Huntington Beach,

Calif.

[73] Assignee: Purex Corporation, Lakewood, Calif.

[22] Filed: April 30, 1970 [21] Appl. No.: 33,183

[52] U.S. Cl 72/4, 72/31, 72/410, 81/313 [51] Int. Cl.....- .1 ..B2ld 55/00 [58] Field ofSearch ..74/17.5;8l/3l3;72/3i,367, 72/409, 410, 453,4

[56] References Cited UNITED STATES PATENTS 3,199,336 8/1965 Batcheller..- ..'.81/3 l3 X June 27, 1972 3,154,981 11/1964 McDurmont ..81/418 X 3,160,890 12/1964 Lefebvre ..72/410 X 2,968,202 1/1961 Evans et al.... .....72/410 X 3,263,481 8/1966 Boyd et a1 ..72/453 3,157,075 11/1964 Filia ..81/313 3,262,342 7/1966 Filia "81/313 3,571,888 3/1971 DeFilippo ..72/421 X Primary Examiner-.1. Spencer Overholser Assistant Examiner-John E. Roethel Attorney-White, l-laefliger and Bachand [5 7] ABSTRACT A 1 crimping tool employing a fluid pressure operated reciprocable ram. Ratchet means is provided to prevent faulty crimping operations including a ratchet tooth movable with the ram and a pawl adapted to engage the tooth against return movement of the ram in response to a crimping stroke of less than a predetermined length.

10 Claims, 5 Drawing Figures PRESSER TOOL WITH FAULTY OPERATION LOCK BACKGROUND OF THE INVENTION 1. Field of the Invention This invention has to do with crimping tools. Particularly, the invention is concerned with tools for crimping a connector sleeve onto a pair of conductors to effect a splice.

In the production of electrical devices it is required to splice routinely numerous wires. Conveniently, splicing is accomplished on a production basis by inserting the ends .of the wires, which may be stnp'pedof insulation or not, into a connector beanie, a conductive metal-lined, deformable plastic cap, and crimping the connector onto the wire ends, to provide both mechanical engagement and electrical connection. While the crimping may be done with hand tools, more reliable and faster operation is realized with power driven crimping tools.

Pneumatically operated tools have been devised for production crimping of connectors. Typically such tools comprise a fluid pressure operated reciprocable ram which, in response to operator actuation of a valve, moves rapidly with crimping force e.g. up to 3,000 pounds of force against the assembled conductors and connector held inasuitable frame.

The crimping action is necessarily obscured from view. Operators are generally unskilled workers who may not berelied on to detect faulty crimps. A temporary loss of fluid pressure through gas cylinder exhaustion or hydraulic fluid leakage may result in a ram working stroke too short to make a truly effective connection. Nonetheless, the crimp may appear satisfactory to the unskilled eye.

2. Prior Art 1 In the past crimping tools have been permitted to operate successive faulty cycles until the ineffective crimps were detected by quality control inspection or by happenstance.

BRIEF SUMMARY OF THE INVENTION It is a major objective of the present invention to provide positive protection against successive faulty crimping operations basically by automatically locking the tool with the beanie in place following a too short ram working stroke.

To carry out this objective, the invention provides a crimping tool including means operable to crimp a connector sleeve onto a conductor pair, a reciprocable fluid pressure'operated ram arranged to actuate the crimping means by forward movement through a working stroke of predetermined length, and ratchet means including a ratchet tooth movable with the ram and a stationary pivotally mounted pawl adapted .to engage the tooth locking the ram against return movement in response to a ram working stroke of less than the predetermined length. The ratchet tooth' may be one of a series of ratched teeth arrangedin spaced relation along the ram longitudinal axis and movable with the ram. A shoulder means is provided on the ram adapted to disengage the pawl from ratchet tooth engagement upon ram movement through a working stroke equal to the aforementioned predetermined length. The crimping tool may also include: a pressurized fluid supply, means to deliver the fluid to the ram to actuate it including a lever operated valve, a tool body having a bore slidably mounting the ram, and a head on the body carrying the crimping means opposite the forward end of the ram. The pawl may be pivotally mounted adjacent the ram with means such as a spring between pawl and body to resiliently press the pawl against the ratchet teeth for sliding engagement therewith during advancing movement of the ram and locking engagement on ram rearward movement, unless displaced from the ram against the biasing force of the pressing means e.g. by interengagement of the ram shoulder and a lug on the pawl arranged to ivot the pawl out of ratchet tooth engagement when the ram is advanced the predetermined stroke length. The tool may further include return spring means biasing the ram rearwardly. The ram is of generally cylindrical configuration and may be relieved along its length to provide the series of ratchet teeth and a radial groove rearwardly adjacent the tooth series to define the ram shoulder in spaced relation to the series across the groove.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described as to an illustrative embodiment in connection with the attached drawings in which: 1

FIG.- 1 is a perspective view of a crimping tool according to the invention;

FIG. 2 is a vertical sectional view thereof taken on line 2-2 in FIG. 1 with the ram in retracted position and the crimping head rotated FIG. 3 is an enlarged detail view partly in section of the crimping tool locking ratchet according to the invention with the ram partially advanced;

FIG. 4 is a view like FIG. 3 with the ram fully advanced;

FIG. 5 is an enlarged detail view in section of the pawl and supporting structure thereof, taken along line 5-5 in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The crimping tool of the present invention is depicted at 1 in FIG. 1. The tool is sized to be hand holdable and includes a generally tubular front body section 2, a tubular rear body section 3 having a manually depressible handle 4, valve means 5 actuable by the handle and pressurized gas or other pressurized fluid inlet 6. Rear body section 3 is connected through gland 7 to front body section 2 which carries crimping head 8 secured by ring nut 9 screwed onto section 2 and fixed with set screw 10. Dual crimping receptacles 11 (FIG. 2) are formed in aperture 12 of the crimping head 8 to receive two sets of wire pairs 13, inserted in B type connectors 14. Exertion of crimping force, e.g. 3,000 pounds of force in the crimping head 8 clamps the connectors 12 against the wire pairs 13 to form aconductive and mechanically strong splice between the wires of each pair.

The present invention is basically concerned with the prevention of faulty crimps by locking of the crimping mechanism when a faulty crimpis produced. In this respect, the particular means for generating the crimping force is not narrowly critical. An illustrative crimping arrangement isdepicted in FIG, 2. v

Referring to FIG. 2, the crimping arrangement includes piston 15 carried piston chamber 16 formed in rear body section 3. Pressurized air or other pressurized'fluid is provided through line 17 to inlet 6 and inlet chamber 18 in the rear body section 3, e.g. through hose adapter 19 threaded into the inlet. Valve 5 controls communication between inlet chamber 18 and a plenum recess 20 in piston chamber l6.'Valve 5 may be of the type having an outer stationary member 21 with circumferentially spaced ports 22 and a relatively movable inner member (not shown) adjustable against biasing spring 23 to alternately communicate chamber 20 with gas inlet chamber 18 and with the atmosphere to vent chamber 16 through vent passages (not shown). The inner valve member may be vertically displaceable by valve stem 24 surmounted by button 25 so that depression of the button actuates the valve stem and depresses the valve inner member to close the ventpassages and open communication between gas inlet chamber 18 and plenum recess 20 and thus piston chamber 16 to actuate piston 15.

Valve actuation is obtained by manipulation of handle 4 adjustably mounted on the rear body section 3 with set screw 26 to be pivotable about pivot pin 27 against valve stem button 25 with leveraged force, conveniently by the thumb of the hand holding the tool.

Once gas pressure communication is established through the valve 5, the piston 15 is actuated. Piston 15 comprises a threaded stem 28, a piston head 29 carrying annular cup seal 30, seal retainer 31, piston rod 32, washer 33-and nut 34 holding the assembly together. Piston rod ,32 is supported at its rearward end 32a by piston head 29 and at its forward end 32b by cylinder head 35 centrally apertured at 350 for movement,

upon piston 15 actuation, into front body section 2. The front body section 2 is threaded into gland 7 to be connected to rear body section 3. The gland 7 has an inturned flange portion 7a engaging cylinder head 35 .against hydraulic pressure dislodgement during tool operation as well as vacuum relief ports 36 which admit air upon the retractive stroke of the piston 15. The from body section 2 'has a stepped central bore 37 with an enlarged rear wall section 38 closed rearwardly by the cylinder head 35 which is partially inserted into the bore for flanged engagement with front body section recess 40 and flange 7a of the gland. The cylinder head 35 is sealed with seal 41. Piston ram 42 having a diametrically enlarged rear portion 43 carrying peripheral seal 44, is slidably mounted in correspondingly enlarged wall section 38 of bore 37 for axial movement therein. The ram 42 is biased rearwardly by the return spring 45 which is supported by annular rib 46 intermediate the ends of bore 37 and acts against shoulder 47 formed by ram portion 43. The piston ram 42 is provided with an axially extended central chamber 48 containing hydraulic fluid 49 and open rearwardly to the entry of piston rod 32 advancing through central aperture past washer 51 and snap ring 52 and against the fluid 49 sealed in chamber 48 by cooperating

seals

41, 44 to drive the piston ram 42 forward against the pressure of spring 45 to actuate ram 53 carried in the forward end of bore 37.

Ram 53 is carried for reciprocable movement in block 54 held in the body bore 37 against forward movement by annular end plate 55 secured between ring nut 9 and retainer spring 56 rearwardly of the block between block annular shoulder 57 and bore rib 46. i

The ram '53 is displaceable forward through the block 54 a distance to engage hammer 58 carrying crimping bosses (not shown) and to drive the bosses a distance sufficient to adequately crimp connectors 14 therein.

In normal operation of the crimping tool 1 then, the tool is hand held, connectors 14 in which wire pairs 13 have been inserted are placed in crimping receptacles 11 in aperture 12 in the crimping head 8. The operators thumb depresses handle 4 the distance permitted by snubber 42 on the handle. This handle movement depresses the inner member of valve and pressurized gas in line 17 flows through the valve ports 22 into piston chamber plenum 20. Piston head 29 moves forward with piston rod 32. The piston rod 32 enters the piston ram chamber 48 filled with hydraulicfluid 49 and drives the piston ram 42 forward multiplying the ramming force by a mechanical advantage equal to the ratio of the squares of the diameters of the enlarged bore section 38 and the piston rod 32. The piston ram 42 strikes the ram. 53 smartly driving the ram against hammer 58 with crimping force. Return spring 59 in crimping head 8 is compressed by hammer 58 movement and acts to return the hammer to its original position.

In the event that fluid 49 is low or the gas pressure in line 17 is inadequate, the force on hammer 58 is insufficient to adequately crimp the connectors 14. That is, the resistance to deforming compression of the connectors 14 is too great for the hammer 58 to overcome and there results a weak splice. The hammer 58 in this event will not travel its nonnal, full distance. Accordingly, the ram 53 which drives the hammer 58 will not travel its full length distance relative to block 54.

Advantage is taken of this relationship of full length ram travel to good crimping results in the present invention. The invention provides ratchet means to lock the ram against return movement in response to a ram forward or working stroke of less length than that predetermined to be adequate for crimping purposes.

With reference to FIGS. 2-5 and particularly FIG. 3 the ram 53 is selectively relieved midway along its length to provide first and second reduced

diameter portions

60 and 61, respectively. Rarn first portion 60 includes annular groove 63 and a series of ratchet teeth 65 rising from the groove to be approximately equal in diameter to unreduced portions of the ram 53. The ratchet teeth 65 are formed as buttress threads, forwardly slanted to permit pawl 69 to slide thereover on forward movement of the ram 53 and rearwardly vertical to prevent ram return movement and are located in extended serial arrangement along the longitudinal axis 66 of the ram. Spaced rearwardly from the ratchet tooth series 64 is the second reduced diameter portion 61 which is of lesser diameter than the first reduced portion 60, and which defines a deeper annular groove 67 circularly of the ram and terminating rearwardly in ram shoulder 68.

The ram 53 is slidably mounted in block 54 as above described. The block 54 is provided with a longitudinal groove 70 (FIG. 5) parallel to the ram axis 66 and oppositely adjacent to ram ratchet tooth series 64 and ram annular groove 67. Pawl 69 comprises

sections

69a and 69b spaced by spacer 69c independently pivotally mounted in the groove 70 by pivot pin 71 to have latch arm 72 extending forwardly, stop arm 73 extending rearwardly and trip arm 74 extending normally to the latch and stop arms and downwardly into annular groove 67 in ram 53. Latch arm 72 is provided with a downwardly projecting tongue 75 parallel to and generally coplanar with trip arm 74 and spaced forwardly of the trip arm opposite the ratchet teeth series 64 and/or groove 63 depending on the relative position of the ram 53 and pawl 69. Latch arm 72 is provided with a notch 76 at its forwardmost extension, adapted to receive leaf spring 77 in compression between the latch arm 72 and notched boss 78 of block 54 in a manner to press the pawl 69 downward in sliding engagement with ratchet teeth 65.

Trip arm 75 is located on the pawl 69 arranged to cause clockwise rotation of the pawl on ram shoulder 68 striking the trip arm during forward movement of the ram 53. Stop arm 73 serves to limit rotation of the pawl 69 by engaging'the ram 53, following a desired amount of pawl rotation.

The ratchet structure operates as follows. In FIG. 2 the pawl 69- is shown in the normal position prior to operation of the ram 53 with the latch arm tongue 75 opposite groove 63 of the ram. Upon actuation of the ram 53 as described above, the ram moves forwardly relative to the pawl 69 to strike the hammer 58 with crimping force. The latch arm 72 is resiliently urged downward by press spring 77 during ram forward movement to keep the tongue 75 in sliding contact with the ratchet teeth 65.

This transitory condition is best shown in FIG. 3. As the ram 53 continues to move forward, ram shoulder 68 advances to contact trip arm 74 which is particularly sized and spaced relative to the ram shoulder to be engaged by the ram shoulder only upon advancement of the ram a full working stroke distance. That is the-distance d? (FIG. 2) between trip arm 74 and ram shoulder 68 is equal to or just slightly less than the distance covered by the ram 53 on a fully effective working stroke so that the ram shoulder engages the trip arm conditioned upon and simultaneously with eflective crimping effort by the ram.

With reference to FIG. 4, the engagement of ram shoulder 68 with trip arm 74 rotates the pawl 69 clockwise, lifting latch arm 72 against press spring 77 and disengaging tongue 75 from ratchet teeth 65 to permit return movement of ram 53 by spring 59 to its original position shown in FIG. 2. Pawl 69 limited in rotation by stop arm 73 is snapped down by the reaction of spring 77 which is bowed oppositely by pawl rotation as shown in FIG. 4.

Pawl sections 690 and 69b are independently pivotable members each carrying respectively tooth engaging tongues 75a and 75b. Tongues 75a and b are offset axially of the ram tooth series 64 a distance less than the pitch distance of the series. Tongue 75a and tongue 75b are thus engageable with the ram 53 at position increments smaller than the pitch distance. That is with the less than pitch distance axial offset of the tongues 75a and b the ram movement may be locked without travel of the ram up to a full pitch distance to accommodate entry of a single tongue 75 into engagement with ratchet teeth 65. In the dual tongue embodiment depicted, one or the other of tongues 75a and 75b will engage the ratchet teeth depending on which tongue is more nearly opposite a tooth space 79.

In this manner the ram 53 may be engaged at increments of movement less than a full pitch distance.

In the event that the ram 53 forward movement is not adequate to crimp effectively, the length of the ram travel is such that the ram shoulder 68 does not engage the trip arm 74 of the pawl 69 and by virtue of the action of press spring 77 the tongue 75 engages a ratchet tooth 65 against ram 53 return movement-The defective splice cannot be disengaged from the crimping tool until the ram stroke is complete i.e. when the short stroke causing defect is corrected; thus necessitating operator attention to the device to remedy the defec- ,tive crimping activity. In addition, the operator is alerted to the defective splice just completed.

I claim:

1. A crimping tool including means operable to crimp a connector sleeve onto a conductor pair, a reciprocable fluid pressure operated ram arranged to actuate the crimping means by forward movement through a working stroke of predetermined length, ratchet means including a series of ratchet teeth in spaced relation along the ram longitudinal axis and movable with the ram, a pawl having a lug and adapted to engage the ratched teeth to lock the ram against return movement in response to a ram working stroke of less than said predetermined length, and ram shoulder means axially spaced from said teeth and arranged to engage the pawl lug to disengage the pawl from ratchet engagement upon ram movement through a working stroke equal to said predetermined length.

2. Crimping tool according to claim 1 including also a pressurized fluid supply and means to deliver said fluid to the ram to actuate the same including amanually operated valve; said pawl operating to lock the ram against rearward movement and further actuation regardless of valve operation following the fluid pressure failing to advance the ram through a working stroke of said predetermined length.

3. Crimping tool according to claim 1 in which said tool also includes a tool body having a bore slidably mounting said ram, a head on the body carrying said crimping means opposite the forward end of the ram, said pawl being pivotally mounted adjacent said ram and means resiliently pressing said pawl against said ratchet teeth for sliding engagement therewith during advancing movement of the ram and locking engagement on ram rearward movement unless displaced from the ram against the force of said pressing means.

4. A crimping tool including means for crimping a connector sleeve onto a conductor pair, a tool body having a bore, a reciprocable fluid pressure operated ram slidably received in said bore for forward movement through a working stroke of predetermined length to actuate the crimping means, said tool body carrying said crimping means opposite the forward end of the ram, ratchet means including a series of ratchet teeth in spaced relation along the ram longitudinal axis and movable with the ram, a pawl pivotally mounted adjacent the ram and adapted to engage the ratchet teeth, said pawl including a lug, means resiliently pressing the pawl against said ratchet teeth for sliding engagement therewith during advancing movement of the ram and to lock the ram against return movement responsive to a ram working stroke of less than said predetermined length, and means carried by the ram to engage said lug to pivot the pawl out of ratchet engagement against the force of said pressing means when the ram is advanced the predetermined stroke length.

S. Crimping tool according to claim 4 in which said resilient pressing means comprises a spring between said pawl and said body biasing said pawl into ratchet tooth engagement.

6. Crimping tool according to claim 5 including also return spring means biasing said ram rearwardly.

7. Crimping tool according to claim 4 in which said ram is of generally cylindrical configuration relieved along its length to provide said series of ratchet teeth and a radial groove rearwardly adjacent said series to form a shoulder on said ram defining said pawl disengaging means in spaced relation to said series of teeth across the groove.

8. Crimping tool according to claim 7 in which the pawl lug extends into said groove and is spaced from said shoulder means a distance less than said predetermined stroke length when the ram is in its rearwardmost position.

9. A crimping tool including means operable to crimp a connector sleeve onto a conductor pair, a reciprocable fluid pressure operated ram arranged to actuate the crimping means by forward movement through a working stroke of predetermined length, and ratchet means including a ratchet tooth series movable with the ram and a pawl adapted to engage the tooth locking the ram against return movement in response to a ram working stroke of less than said predetennined length, said pawl comprising first and second independently pivotable members each carrying a tooth engaging tongue, said tongues being relatively offset axially of said ram tooth series a distance less than the pitch distance of said series to be engageable with said ram at position increments smaller than said pitch distance.

10. Crimping tool according to claim 9 in which said fluid supply comprises gas under pressure and said ram has a central bore defining a piston ram chamber and filled with hydraulic fluid, and includingalso a piston'ram movable in said chamber against said hydraulic fluid to drive said ram, said piston ram having a piston head of a greater area than said piston ram and in valve-controlled communication with said pressurized fluid supply to transmit fluid pressure to said piston ram head and a multiple of said fluid pressure through said piston ram to said ram.

Claims

2. Crimping tool according to claim 1 including also a pressurized fluid supply and means to deliver said fluid to the ram to actuate the same including a manually operated valve; said pawl operating to lock the ram against rearward movement and further actuation regardless of valve operation following the fluid pressure failing to advance the ram through a working stroke of said predetermined length.

5. Crimping tool according to claim 4 in which said resilient pressing means comprises a spring between said pawl and said body biasing said pawl into ratchet tooth engagement.

9. A crimping tool including means operable to crimp a connector sleeve onto a conductor pair, a reciprocable fluid pressure operated ram arranged to actuate the crimping means by forward movement through a working stroke of predetermined length, and ratchet means including a ratchet tooth series movable with the ram and a pawl adapted to engage the tooth locking the ram against return movement in response to a ram working stroke of less than said predetermined length, said pawl comprising first and second independently pivotable members each carrying a tooth engaging tongue, said tongues being relatively offset axially of said ram tooth series a distance less than the pitch distance of said series to be engageable with said ram at position increments smaller than said pitch distance.

10. Crimping tool according to claim 9 in which said fluid supply comprises gas under pressure and said ram has a central bore defining a piston ram chamber and filled with hydraulic fluid, and including also a piston ram movable in said chamber against said hydraulic fluid to drive said ram, said piston ram having a piston head of a greater area than said piston ram and in valve-controlled communication with said pressurized fluid supply to transmit fluid pressure to said piston ram head and a multiple of said fluid pressure through said piston ram to said ram.