US3491577A

US3491577A - Collet-type crimping tool

Info

Publication number: US3491577A
Application number: US669825A
Authority: US
Inventors: Hermann E F C Lingenbrink
Original assignee: Thomas and Betts Corp
Current assignee: ABB Installation Products Inc
Priority date: 1967-09-22
Filing date: 1967-09-22
Publication date: 1970-01-27
Anticipated expiration: 1987-01-27

Description

Jail. 27, 1970 H. E. F. c. LINGENIBRINK 3,491,577

COLLET-TYPE CRIMPING TOOL Filed Sept. 22, 1967 3 Sheets-Sheet 1 INVENTOR.

ATTORNEYS.

i 1970 H. E. F. C(LINGENBRINK 3,491,577

COLLET-TYPE CRIMPING TOOL 5 Sheets-Sheet 2 Filed Sept. 22, 1967 INVENTOR. HewmmE/I'C'Lzwuawnx RNEYS J n. 27, 1970 HEwF.-C. -LINGENBRINK 7 COLLET-TYPE GRIMPING TOOL Filed Sept. 22) 19,67 5 Sheets-Sheet 3 K V WM W Q INVENTOR. o 1 /59/1190 ificb/vaewemm Z ATTORNEYS.

United States Patent 3,491,577 COLLET-TYPE CRIMPING TOOL Hermann E. F. C. Lingenbrink, Hilltown Township, Bucks County, Pa., assignor to The Thomas & Betts Co., Elizabeth, N.J., a corporation of New Jersey Filed Sept. 22, 1967, Ser. No. 669,825 Int. Cl. B21d 9/08, 41/04 US. Cl. 72402 10 Claims ABSTRACT OF THE DISCLOSURE I This invention relates to a collet-type crimping tool. More particularly, this invention relates to a collet-type crimping tool for circumferentially crimping electrical connectors.

It is often necessary to make electrical connections between electrical conductors in crowded quarters such as inside a computer or an electrical appliance. In many instances, the connections required techniques which, on the one hand, did not effect gas-tight connections while on the other hand, allowed foreign matter such as solder material to deposit in the area surrounding the connections. In order to overcome these disadvantages, tools have been developed which would provide satisfactory connections; however, these tools have generally required a relatively large working space. In such cases, the electrical connections have not been placed in as close a spacing as would otherwise be possible. Also, such tools have frequently required large forces for operation since the mechanical advantages of the tools have been relatively low. Thus, such tools have generally been difficult to use manually and in some instances have required auxiliary power tools for effectin g the connections.

Accordingly, it is an object of the invention to provide a tool for making electrical connections in a limited space.

It is another object of the invention to permit the spacing of electrical connections to be as close as possible.

It is another object of the invention to provide a tool capable of making gas-tight electrical connections.

It is another object of the invention to provide a tool capable of making electrical connections mechanically without depositing foreign matter in the environment of the connections.

It is another object of the invention to provide a crimping tool which is simple to use manually.

It is another object of the invention to provide a crimping tool which has a relatively large mechanical advantage.

Briefly, the invention provides a crimping tool having a handle section and a removable head section. The head section of the crimping tool includes a pair of collets which are slidably mounted one within the other. The inner collet is internally formed at one end so as to receive a deformable connector within a plurality of split sections which are normally spaced apart when the connector is placed therein. The outer collet is formed in a substantially complementary manner to the inner collet to receive the inner collet and to effect a closing of the split sections of the inner collet upon retraction of Patented Jan. 27, 1970 the inner collet into the outer collet. For example, the outer collet is formed with a conical surface which engages a complementary outer surface on the split sections of the inner collet.

In one embodiment, the inner collet has four split sections which receive a connector and which exert a circumferential force on the connector when brought together in order to reduce the connector circumferentially.

In another embodiment, the inner collet is formed with two semi-cylindrical split sections which are suitably recessed to pass over a frangible connector which has been previously compressed onto a tab of a bus bar. However, in this embodiment, the split sections are so spaced apart that upon being brought together, the split sections impose a pair of substantially opposed compression forces on the connector while also allowing disruptive tensile stresses to be created in the connector at approximately right angles to the compression forces on the connector. Thus, upon movement of the inner collet into the outer collet and the development of a disruptive tensile stress in the connector, the connector will fracture in such a manner to be readily removed from the tab.

The head section of the crimping tool further includes a pair of collet holders, each of which receives a collet in a secure manner.

The handle section of the crimping tool operates as a means for moving the collets of the head section with respect to one another such that the inner collet moves into the outer collet to allow the conical surface of the outer collet to bring the split sections together. The handle section includes a pair of bell cranks and a pair of handles. The bell cranks are connected to the handles and the collet holders in a manner so as to effect a reciprocal movement between the collet holders upon closing and opening of the handles. For example, upon closing of the handles, the bell cranks each pivot independently of the other to retract the inner collet holder into the outer collet holder.

In use, as the collet holders move with respect to each other so do the collets. Thus, the inner collet retracts into the outer collet. At the same time, the split sections close upon a received connector under the direction of the outer collet. Where used to compress the connector onto a wire wrap post, the connection is made under a circumferentially applied compression force such that a uniform contact between the connector and post is facilitated. Where the tool is used to fracture a frangible connector so as to remove the connector from the post, the generated force develops a disruptive tensile stress in the connector.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompany drawings in which:

FIG. 1 illustrates a partially broken view of a crimping tool of the invention;

FIG. 2 illustrates a fragmentary side view of the crimping tool of FIG. 1;

FIG. 3 illustrates a perspective view of the inner collet with a received connector in place;

FIG. 4 illustrates a cross-sectional View of the crimping tool of FIG. 1 in a position wherein a connector is compressed onto a wire wrap post;

FIG. 5 illustrates a partially broken view of an inner collet used for fracturing a frangible connector; and

FIG. 6 illustrates a view taken of line 6-6 of FIG. 5.

Referring to FIG. 1, the crimping tool 10 is constructed with a handle section 11 and a head section 12 which is removably secured to the handle section 11. The handle section 11 includes a pair of levers 13 which are pivotally mounted together in a known manner so as to he in a closed position when the free ends of the levers 13 are brought together and to be in an open position when the free ends of the levers 13 are spaced apart, for example, under a spring biased force.

The head section 12 of the tool includes an inner collet 14, an inner collet holder 15 in which the inner collet 14 is secured, an outer collet 16 in which the inner collet is slidably mounted and an outer collet holder 17 in which the outer collet 16 is secured and the inner collet holder 15 is received.

Referring to FIG. 3, the inner collet 14 has a solid cylindrical body portion 18 which is threaded at one end for threaded engagement with the inner collet holder 15. The other end of the cylindrical body portion 18 is integral with a plurality of split sections 19, for example, four which project from the body portion 18 in spaced relation to each other. The split sections 19 are exteriorly shaped to form a cylindrical section '20 of less diameter than the body portion 18 and a conical section 21 which flares outwardly from the axis of the inner collet 14. In addition, the split sections 19 form a recess 22 in the forward end of the inner collet 14 for receiving a circumferentially compressible connector 23 to which a plurality of conductors 24 have been previously secured. A bore 25 (FIG. 4) is also formed within the split sections 19 and body portion 18 to permit the split sections 19 to be brought together and to permit the reception of elongated wire wrap posts.

Referring to FIG. 1, the outer collet 16 has a bore 26 which includes a concial mouth 26' in which the conical section 21 of the inner collet 14 is matingly received. When the tool 10 is in the opened position, the conical section 2.1 lies near the opening of the conical mouth 26. In addition, the outer collet 16 has a threaded stem 2?, a barrel portion 28 which has flats 29 on two diametric sides and a collar 30 between the threaded stem 27 and barrel portion 28. The threaded stem 27 is threaded into an axial threaded recess 31 in the outer collet holder 17 in a secure manner. The outer collet holder 17 has a pair of bifurcated legs 32 which defme a recessed area 33 within the holder 17. Each bifurcated leg 32 has a pin 34 mounted between the bifurcations which is held in place, for example, by suitable clip rings 35 partialy received in grooves 36 at the ends of the pin 34.

The inner collet 1-4 which is slidably received in the bore 26 of the outer collet 16 passes through the recess 31 and a bore 37 in the outer collet holder .17. The threaded body portion 18 of the inner collet 14 is threaded into a suitably threaded bore 38 in the inner collet holder 15 in an adjustable manner. The inner collet holder 15 is formed in an H-shape so as to have a pair of legs 39 extending from each of two sides of the holder 15. Each leg 39 is formed with an elongated slot 40 which is aligned with a slot in the opposite leg 39 and through which a pin 42 of smaller diameter than the length of the slot 40 is passed. Each pin 42 is held in place by clip rings 43 in a manner as pins 34 in order to be slidably retained within the slot 40.

Referring to FIGS. 1 and 2, the handle section 1.1

includes a pair of hell cranks '44 which connect they handle section 11 and head section 12 together. Each bell crank 44 is pivotally mounted at one end on a pin 45 secured in a lever 13 and at the other end on the

pins

34, 42 in the

respective holders

17, 15. The pins 45 in the levers .13 are disposed in planes parallel to the longitudinal axis of the tool 10 which lies between the

pins

34, 42 in the

holders

17, 15 when the tool is in the opened position.

Referring to FIG. 4, in order to use the crimping tool 10 in crimping, for example, a connector 23 such as de scribed in copending US. patent application entitled Posttype Solderless Electrical Connector having conductors 24 secured therein onto a square shaped post 46 of a bus bar 47, the connector 23 is placed in the recess 22 of the inner collet 14. Next, the connector 23 which has a central square shaped aperture of substantially complementary shape to the post 46 is passed over the post 46 with the conductors 24 disposed around the post 46. The levers 13 of the handle section 11 are then brought together. This causes the ends of the bell cranks 44 secured to the levers .13 to pivot away from each other about the axes of the pins 34. At the same time, the pins 42 are slidably moved within the slots 40 of the inner collet holder 15 in a direction outwardly of the axis of the tool 10. Thus, as the bell cranks 44 pivot in this direction, the

holders

15, 17 are caused to move with respect to each other axially of the tool axis such that the inner collet holder 15 is drawn towards the levers 13. This causes the inner collet 14 to retract into the outer collet .16 such that the conical mouth '26 forces the split sections 19 to move together circumferentially. As the split sections 19 continue to move together a compressive force is exerted circumferentially upon the circumference of the connector 23 so as to circumferentially reduce the connector 23 about the post 46. The force generated by the tool 10 on the connector 23 is sufficient to form a substantially gas-tight connection between the connector 23, conductors 24 and post 46.

After a connection has been rnade the levers 13 are released so as to spring back to their original position.- This causes the inner collet holder .15 to move back into the recess area 33 defined by the outer collet holder .17 While also causing the split sections 19 to spring back to their initial unstressed positions.

Since the head section 12 of the crimping tool 10 is removably secured to the bell cranks 44, the collets of the head section 12 described above can be replaced by other collets which are sized to cooperate with deformable connectors of other shapes than that referred to above. For example, where a connector is shaped in a manner so as to have a generally rectangular cross-section with two rounded sides and conductor receiving slots in the rounded sides, the inner collet is formed with a recess to receive the connector. In addition, the conical section of the inner collet and the conical mouth of the outer collet are formed with surfaces making an angle of about 7 with the axis of the tool so as to provide a mechanical advantage of about 8 to 1 thereat.

Other collets can also be used the crimping tool so as to generate disruptive tensile forces or stresses in frangible connectors which have been previously secured to the tabs of a bus bar. For example, referring to FIGS. 5 and 6, an inner collet 50 is formed with a cylindrical body portion 51 which is threaded at one end for securement in an inner collet holder as above and a pair of semi-cylindrical split sections 52 at the other end. The split sections 52 are shaped exteriorly to have a conical section 53 and shaped interiorly to define a bore 54 and an oval recess 55 axially behind the bore 54 for receiving elongated posts. The split sections 52 are also spaced apart a distance which is sufiicient to cause a distribution of the compressive forces imposed on the split sections 52 by an outer collet, as described above, to effect substantially a pair of opposed compression forces on an enveloped frangible connector in the bore 54. For instance, with a bore having a diameter of 0.130 inch, a recess of 0.100 inch by inch, an outside diameter of 0.200 inch, and a 5 conical section, the split sections are spaced 0.015 inch apart.

In use on a crimping tool, the inner collet 50 is positioned over a connector connected to a tab and then retracted into an outer collet as above. The split sections 52 thus generate a pair of opposed compressive forces on the connector while also imposing tensile forces in the connector at points generally within the plane of the space between the split sections 52. Before the split sections 52 are brought into contact, disruptive forces are generated in the connector so as to cause the connector to fracture and thereby become disconnected from the tab.

The crimping tool of the invention possess a mechanical advantage which includes the mechanical advantage due to the relatively slidable conical surfaces of the conical section of the inner collet and the conical mouth of the outer collet. For example, with these conical surfaces each being formed on an angle of 12 the mechanical advantage provided by such surfaces is approximately 5 to 1. This mechanical advantage when multiplied by the mechanical advantage of the bell cranks and levers of the tool imparts a relatively large mechanical advantage to the tool. A further increase can be achieved by decreasing the angle of the mating conical surfaces, for example, to 5. Also, the position of the inner collet within the inner collet holder can be adjusted so as to limit the amount of movement of the inner collet into the outer collet holder.

The crimping tool is provided with dimensions so as to be used in making electrical connections with closely spaced terminals such as the tabs of a bus bar. For example, the outer collet is dimensioned with a barrel section of /2 inch diameter and flats which are spaced inch apart. In addition, the barrel section has a length of W inch.

The crimping tool is capable of being easily handled and used manually. Thus, a relatively large number of electromechanical connections can be made. In this regard it is noted that a rack and gear arrangement can be substituted for the bell cranks in order to effects the relative movement between the inner and outer collet holders.

Further, the respective recesses and bores in the tool for receiving the posts during a crimping operation are so elongated that a number of connectors can be crimped into a single wire wrap post.

Having thus described the invention, it is not intended that it be so limited as changes may be readily made therein without departing from the scope of the invention. Accordingly, it is intended that the subject matter described above and shown in the drawings be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A crimping tool comprising an outer collet having a bore therethrough and a concial mouth at one end of the bore;

an inner collet slidably mounted in the bore of said outer collet, said inner collet having a plurality of split sections at one end, said split sections defining a recess therebetween and having a conical exterior surface disposed in mating relation with the conical mouth of said outer collet, said conical exterior surface being disposed on an angle of from 5 to 12 relative to the axis of said inner collet; and

means for moving said inner collet into said outer collet to cause said split sections to move towards each other.

2. A crimping tool as set forth in claim 1 wherein said inner collet has a pair of semi-cylindrical split sections.

3. A crimping tool comprising an outer collet having a bore therethrough and a conical mouth at one end of the bore;

an inner collet slidably mounted in the bore of said outer collet, said inner collet having a plurality of split sections at one end, said split sections defining a recess therebetween and having a conical exterior surface disposed in mating relation with the conical mouth of said outer collet; and

means for moving said inner collet into said outer collet to cause said split sections to move towards each other, said means including an outer collet holder secured to said outer collet, and an inner collet holder within said outer collet holder adjustably secured to said inner collet.

4. A crimping tool as set forth in claim 3 wherein said means further includes a pair of pivotally mounted levers and a pair of hell cranks, each of said bell cranks being pivotally secured at one end to one of said levers and at the opposite end to each of said inner and outer collet holders whereby pivoting of said levers towards each other causes pivoting of said bell cranks away from each other to move said inner collet holder relatively inwardly of said outer collet holder.

5. A crimping tool comprising a handle section and a head section removably mounted on said handle section, said head section including a pair of collets, one of said collets being slidably mounted within the other of said collets, said one collet having a plurality of spaced split sections at one end thereof, said other collet having an internal surface opposite said split sections of tapered dimensions, and a pair of collet holders, each of said holders being independently secured to a respective collet, said handle section including means for mov ing said collet holders with respect to one another to cause said one collet to retract within said internal surface whereby said split sections are brought together.

6. A crimping tool as set forth in claim 5 wherein said split sections have external surfaces defining a coni' cal surface and said internal surface of said other collet has a complementary conical surface in mating engagement with said external surfaces.

7. A crimping tool as set forth in claim 5 wherein said one collet has a pair of semi-cylindrical split sections defining a recess for receiving a frangible electrical connector therein.

8. A crimping tool as set forth in claim 5 wherein said one collet has at least two pair of split sections defining a recess for receiving a circumferentially deformable connector therein to circumferentially reduce the received connector upon bringing together of said split sections.

9. A crimping tool as set forth in claim 5 wherein said one collet is adjustably secured in one of said collet holders for adjustably positioning said split sections within said other collet.

10. A crimping tool as set forth in claim 5 wherein said means includes a pair of pivotally mounted levers and a pair of hell cranks, each of said bell cranks being pivotally mounted at one end on each of said collet holders and being pivotally mounted at the opposite end on one of said levers whereby pivoting of said levers causes said bell cranks to pivot in a manner to move said collet holders axially with respect to each other.

References Cited UNITED STATES PATENTS 2,225,345 12/ 1940 Lamoreaux 72-402 2,999,405 9/1961 Ewart 72-402 3,234,776 2/1966 Stoltz 72-410 CHARLES W. LANHAM, Primary Examiner MICHAEL J. KEENAN, Assistant Examiner US. Cl. X.R. 72-410