US3757408A

US3757408A - Tool for assembling a connector assembly

Info

Publication number: US3757408A
Application number: US00238807A
Authority: US
Inventors: S Shemtov
Original assignee: ELECTRICAL FITTING CORP
Current assignee: ELECTRICAL FITTING CORP
Priority date: 1972-03-28
Filing date: 1972-03-28
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11

Abstract

A power tool for tightening a connector on an electrical conduit and includes a first stationary chuck having spring contracted first jaws and a driven second chuck having spring expanded second jaws axially spaced from the first jaws and spring biased toward the first jaws to expand them. The second chuck is positioned in a housing and the second jaws cooperate with a cam surface on the housing inside face so that the advance of the second chuck contracts the second jaws and the second chuck is connected by a torque limiting clutch to a drive shaft and is provided with an inside shoulder. By inserting the connector and conduit into the tool, any inner ferrule or sleeve is threaded onto the convolutions of the conduit inner surface so as to fully engage the conduit and the end of the connector pushes the second chuck rearwardly when the gland nut and body flats register with the first and second jaws respectively to close the jaws and to engage the clutch.

Description

ilnfited States Patent 1 Shemtov 1 1 TOOL FOR ASSEMBLING A CONNECTOR ASSEMBLY [75] Inventor: SamiShemt0v,Centrallslip,N.Y.

[73] Assignee: Electrical Fitting Corporation,

East Farmingdale, NY.

[22] Filed: Mal. 28, 1 972 [21] Appl. No.: 238,807

[52] US. Cl. 29/237, 29/240 Primary Examiner.lames L. Jones, Jr. Att0rneyHoward C. Miskin 1451 Sept. 11, 1973 [57] ABSTRACT A power tool for tightening a connector on an electrical conduit and includes a first stationary chuck having spring contracted first jaws and a driven second chuck having spring expanded second jaws axially spaced from the first jaws and spring biased toward the first jaws to expand them. The second chuck is positioned in a housing and the second jaws cooperate with a cam surface on the housing inside face so that the advance of the second chuck contracts the second jaws and the second chuck is connected by a torque limiting clutch to a drive shaft and is provided with an inside shoulder. By inserting the connector and conduit into the tool, any inner ferrule or sleeve is threaded onto the convolutions of the conduit inner surface so as to fully engage the conduit and the end'of the connector pushes the second chuck rearwardly when the gland nut and body flats register with the first and second jaws respectively to close the jaws and to engage the clutch.

13 Claims, 6 Drawing Figures PATENTEB sum 1 or 2 Fig.2

TOOL FOR ASSEMBLING A CONNECTOR ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates generally to improvements in power tools and it relates more particularly to an improved power tool for tightening a connector on a conduit and more specifically it relates to an improved power tool for tightening the gland nut of a threaded connector on a liquid-tight flexible electrical conduit.

A liquid-tight electrical conduit in widespread use is of the metal helix type covered with a continuous flexible plastic sheath. In order to facilitate the attachment of the conduit to a fixture or junction box, threaded connectors are attached to the ends of the conduit which is cut to the desired length. These connectors generally include a tubular body member threaded at opposite ends and provided with an intermediate tool cooperating section; such as hexagonal flat surfaces, knurled or striated, surfaces or ribs, hereinafter called body nut. A coupling or lock-nut engages one of the threaded ends. The opposite threaded end is engaged by a nut which tightens a gland housed in the body member to effect a liquid-tight connection between the coupling and the conduit, the conduit being embraced by the body member wall and a clamping sleeve engaging the end of the conduit. The lock-nut must remain loose and is used to hold the connector in operative position. While this type of conduit connector is highly satisfactory, its attachment to conduit previously was by means of hand tools, which was an expensive and time consuming procedure. This is especially true where large numbers of connectors must be connected.

SUMMARY OF THE INVENTION Still another object of the present invention is to provide an improved power tool for tightening the gland nut of a connector on a liquid-tight sheathed helical electrical conduit. a

A further object of the present invention is to provide a power toolfor tightening the gland nut on an electrical conduit connector with the proper torque and to uniformly connect the connector to the conduit.

Yet another object of the present invention is to provide a power tool for tightening a connector onto a conduit and to fully engage the inner ferrule with the conduit prior to attaching the connector to the conduit.

Still a further object of the present invention is. to provide a tool of the above nature characterized by its compactness, simplicity, ruggedness, ease and convenience of application and use, and high reliability.

The above and other. objects of the present invention will become apparent from a reading of the following description thaken in conjunction with the accompanying drawings which illustrate a preferred embodiment thereof.

In a sense the present invention contemplates the provision of a tool for tightening a connector to a conduit, said connector including a body member having an externally threaded portion and an integrally formed flats or first nut defining portion and a gland tightening second nut engaging the externally threaded portion on one side of said first nut portion and a lock-nut on the opposite side of said first nut portion, comprisinga first relatively stationary chuck member having first jaws inwardly and outwardly movable between advanced contracted and retracted expanded positions respectively, a second chuck member axially spaced from and coaxial with and rotatable relative to the first chuck member and having second jaws inwardly and outwardly movable between advanced contracted and retracted expanded positions respectively, jaw closing means for urging said first and second jaws toward their contracted positions when said nuts register with respective jaws, and drive means for rotating said second chuck member.

In its preferred form the improved tool includes a base member on which the first chuck and a cylindrical casing having an open front end are coaxially mounted. The first chuck has opposite blocks having wells which converge toward the second chuck housing and the first jaws register with the well and are spring biased rearwardly to contract the first jaws. The second chuck includes a tubular body member rotatable and axially movable in the casing and having the second jaw mem bers slidable in transverse grooves in the front face of the body member and engaging an annular cammed surface on the inside face of the casing so that rearward axial movement of the second chuck contracts the jaws against a spring bias. The rear end face of the second chuck body member is serrated as is the confronting front face of a drive member located in the housing rear, the faces defining a torque limiting clutch. The drive member is motor driven and spring means biases the second chuck forwardly to bear on the first jaws so that the jaws are normally expanded. A peripheral shoulder is located on the inner face of the second chuck body member and is so related to the second jaws that when the connector is inserted in the tool and the connector inner end engages the shoulder, the connector body member nut registers with the second jaws and the gland nut registers with the first jaws. Advance of the connector effects the contraction of the jaws and the engagement of the clutch.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a perspective viewof the improved tool and a connector mounted on conduit in a position to be applied thereto;

FIG. 2 is a sectional view taken along line 2 2 'in FIG. 1; I

FIG. 3 is'a sectional view taken along line 3 3 in FIG. 2;

FIG. 4 is a side elevation view of FIG. 3;

FIG. 5 is a view similar to FIG. 2 but with the connector shown in working association with the tool; and

FIG. '6 is a sectional view taken along lines 6 6 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing which illustrate a preferred embodiment of the present invention, the reference numeral 10 generally designates the improved power tool which is applied to the tightening of a connector 11 mounted at the end of a conduit 12 such as, for example, of the type including a helically wound flexible tube having inner convolutions encased in a flexible plastic sheath, for example, of polyvinyl chloride. The connector 11 is of known construction and includes an integrally formed metal tubular body member having an exteriorly threaded outer section 13 and an enlarged exteriorly threaded inner section 14. A moisture proofing gland 8 is housed in section 14 and is compressed by the tightening of a hex nut 17 engaging section 14, and a connector securing nut or locknut 18! engages the threaded section 13. In applying the connector 11 to the conduit 12, the end of the conduit 12 is slipped between a sleeve 9 in section 14 to fully engage both and the packing gland 8, and the nut 17 is tightened by the tool to compress the gland and effect a liquid-tight connection.

The improved tool 10 includes a base plate 19 having affixed to the rear thereof a bracket 20 having an arcuate recess 21 for supporting an electric drive motor, not shown, which powers the tool 10. Mounted on the front face of plate 19, are a stationary forward first chuck 22, and a coaxial cylindrical casing or housing having an open front end confronting and closely spaced from chuck 22. The chuck 22 includes a pair of similar transversely spaced blocks 23 secured to base plate 19 and having formed therein wells 24 of rectangular transverse cross section and extending from the rear inner corners of respective blocks 23 to approximate medial points shortly forward of the front faces of the blocks 23.

Slidably telescoping each of the wells 24 is a first jaw member 26 of a transverse cross section corresponding to that of well 24 and have a longitudinal flat inside face 27 parallel to the inside faces 28 of blocks 23 and perpendicular to base plate 19 and a transverse planar front face 28. A helical compression spring is located in each well 24 and is entrapped between the base of the well 24 and the confronting face of jaw member 26. When jaws 26 are in a position with their faces 27 coplanar with block faces 28, the jaw faces 29 are shortly rearwardly of the rear faces of blocks 23 and springs 30 are highly compressed.

The housing 25 has a cylindrical peripheral wall 32 and an axially bored rear end wall 33 and is open at its front end. The inside face of peripheral wall 32, slightly rearwardly of the front end thereof, is bevelled to form an inwardly rearwardly inclined, peripheral, cam defining face 34 which terminates in a forwardly directed cylindrical inside face 36. A longitudinally stepped shaft 37 is coaxial with casing 25 and includes an enlarged rear section 38 projecting through and joumalled in the central bore in rear wall 33, and extending about midway into casing 25, a short intermediate section 39 of lesser diameter than shaft section 38 and delineated therefrom by an integrally formed peripheral flange 40 with a cylindrical outer face, and relatively small diameter elongated front shaft section 41 extending from shaft section 39 through the front of casing 25 and forward of chuck 22 and delineated from section 39 by a forwardly converging conically shaped guide shoulder 42. A drive coupling 43 is attached to the outer end of shaft section 38 to facilitate its connection to a drive motor mounted on bracket 20.

Attached to and rotatable with shaft 37 is the drive member 44 of a torque limiting disengagable clutch which is housed in the rear end of casing 25. Drive member 44 includes a forward peripheral wall 46 of greater inside diameter than the outside diameter of shaft section 38 and a centrally apertured rear end wall 47 abutting casing wall 33 and secured to shaft section 38 by a pin engaging aligned transverse bores in shaft section 38 and wall 47. The front face of drive member 44 has saw tooth serrations 49 formed therein with leading inclined faces 50 facing in the direction of rotation of clutch member 44.

A second chuck and driven clutch member 52 is positioned in the forward section of casing 25 and is rotatable and axially slidable on shaft 37. The member 52 comprises an integrally formed body member including a cylindrical wall 53 extending from the front end of casing 25 and terminating at its rear end in an inwardly directed peripheral flange 54 which extends to the face of shaft section 38 and is movable into engagement with the rear face of shaft-flange 40. An annular wall 56 projects rearwardly from the rear face of flange 54 and has a serrated rear face mating the front face of clutch member 44. An annular space 58 is delineated by the confronting faces of

walls

46 and 56, and shaft section 38 and a helical compression spring 59 is positioned in space 58 and is entrapped between

walls

47 and 54 to urge member 52 to its forward position as shown in FIG. 2. A collar 60 is secured to the inside face of wall 53 forward of flange 54 and slidably and rotatably engages shaft section 39 to permit the axial movement of member 52.

Formed in the front end of wall 53 are a pair of opposite rectangular grooves 63 extending substantially tangentially to the inner face of wall 53 between the inner and outer faces of wall 53. Slidably engaging each of the grooves 63 is a second jaw 64 including an arm 65 nesting in groove 63 and provided at its outer end with a forwardly projecting leg 66. The rear outer corner of each jaw 64 is bevelled to provide a face 67 which complements and is engagable with cam face 34. An annular plate 68 is secured to the front face of wall 53and is provided along its inner edge with rearwardly projecting ears 69 covering the grooves 63 proximate the inside face of wall 53. A helical compression spring 70 is entrapped between each ear 69 and a corresponding jaw leg 66 to spring bias the jaws 64 to their expanded condition, as shown in FIG. 2, the jaws being contractable to load springs 70. The axial distance between the front face of collar 60 and jaw legs 66 is about equal to that between. the end edge of coupling section 13 and body nut section 16.

Considering now the operation of the improved tool which, in its ready condition as shown in FIG. 2, has chuck member 52 biased forwardly by spring 59 so that the member 52 is disengaged from the motor drive clutch member 44, the annulus 68 bears on and expands jaws 26 and springs 70 expands jaws 64. To tighten connector 11 onto conduit 12, the conduit is slipped into the space in the connector between the inner sleeve ferrule 9 and the plastic ring 8 and the connector l1 and conduit 12 are slipped onto shaft section 41 and advanced until connector section 13 beats on a collar 60 and tapered shaft portion 42 engages and rotates ferrule 9 to fully engage conduit 1]. The threads of ferrule 9 mate with the threads of the convolutions of the inner surface of conduit 12. The

open jaws

26 and 64 permit the passage of

nuts

18, 16 and 17 and the connector is axially located by shaft section 39. By further advance of the connector 11, which bears on collar 60, member 52 is moved rearwardly into driven engagement with clutch member 44, the jaws 64 are contracted by the action of cam face 34 on the rearwardly moved jaw faces 67 to engage body nut 16, and the jaws 26 are released by the rearwardly moved annulus 68 to permit the closing of jaws 26 by springs 30 and the engagement of gland nut 17.

The rotation of the chuck member 52 rotates the coupling body while gland nut 17 is held stationary by jaws 26 to tighten the gland nut 17. When the gland nut 17 is sufficiently tightened the resulting back torque on chuck member 52 causes the advance thereof by the confronting serrated edges of clutch members 44 and S2 and a chattering which is an indication of the completion of the gland nut tightening. By releasing the pressure applied by the operator to the connector, the member 52 is advanced to its forward position to effect the expansion of

jaws

26 and 64 and the disengagement of

nuts

16 and 17 to permit the withdrawal of conduit 12 and the gland compressed connector 11.

The present invention allows the connector to be properly tightened on the conduit after the ferrule fully engages the conduit and the lock-nut 18 to remain loose for future removal and connection to the electrical outlet box or surface. Also, while the clutch members are shown having mating serration teeth, other elements can be used such as friction, teeth or the like. Also, while the driving member of the clutchis shown fastened to the driving shaft by a pin, any other convenient connecting means can be used.

While the body nut" as previously defined included a surface that was machined or roughened in some manner, a smooth surface on the connector could be used with suitable changes in the surfaces of the coopcrating jaws.

Further, while the present invention was illustrated being used with a connector, other fittings, such as couplings may be used. Also, the connector or other fitting may be initially positioned on the shaft of the unit and the conduit inserted on the unit. While the metal ferrule 9 may be loosely mounted in the connector, it could be made to be firmly held within the connector so that rotation of the connector rotates the ferrule to tighten it onto the conduit.

While there has been described and illustrated a preferred embodiment of the present invention it is apparent that numerous alterations, omissions and additions may be made without departing from the spirit thereof.

What I claim is:

l. A tool for tightening a connector to a conduit said connector including a body member having an externally threaded portion and an integrally formed first nut defining portion and a gland tightening second nut engaging said externally threaded portion, comprising a first relatively stationary chuck member having first jaws movable between advanced contracted and retracted expanded positions respectively, a second chuck member axially spaced from and coaxial with and rotative relative to the first chuck member and having second jaws movable between advanced contracted and retracted expanded positions respectively, jaw closing means for urging said first and second jaws toward their contracted positions when said nuts register with respective jaws, and drive means for rotating said second chuck member.

2. The tool of claim 1 including first spring means normally urging said first jaws toward their advance positions and means normally urging said jaws toward their retracted positions against the influence of said first spring means and responsive to the registry of said nuts of said connector with respective chucks for releasing said jaws toward their advance positions.

3. The tool of claim 1 wherein said drive means includes means for limiting the torque imparted to said second chuck.

4. The tool of claim 1 wherein said drive means comprises a clutch including a drive section and a driven section connected to said second chuck and axially movable between an advanced clutch position toward said drive section and a retracted declutch position away from said drive section.

5. The tool of claim 4 including spring means urging said clutch driven section toward said retracted declutch position.

6. The tool of claim 1 wherein said second chuck is axially movable between a retracted position proximate said first chuck and an advanced position relatively .remote from said first chuck, said means for closing said second jaws being responsive to the advance of said second chuck.

7. The tool of claim 6 wherein said first jaws advance to a closed position in response to the advance of said second chuck.

8. The tool of claim 6 including spring means normally retracting said second jaws.

9. The tool of claim 1 including a housing having a cylindrical first bore extending through the front end of said housing and having a cam defining forwardly outwardly inclined peripheral shoulder proximate its forward end, said second chuck comprising a cylindrical body member slidably and rotatably registering with said first bore and having a coaxial second bore formed therein and open at its front and having a peripheral shoulder in its inner face rearwardly of the front thereof, said second jaws being slidably supported in said body member for movement to an advanced position extending into said bore and spring urged toward a retracted position and engaging said cam surface whereby rearward movement of said body member advances said second jaws and spring means normally forwardly urging said body member.

10. The tool of claim 9 including a drive member located in said housing rearwardly of said body member and having a front clutch face, said body member having a rear clutch face confronting said front clutch face and being movable with said body member into and out of engagement with said front clutch face, and spring means normally urging said body member forwardly to separate said clutch faces.

11. The tool of claim 10 including a shaft coaxial with said housing and projecting through the rear of said housing and forwardly beyond said first chuck, said drive member being affixed to said shaft. 1

12. The tool of claim 11 wherein said connector further includes a ferrule for engaging the inner surface of the conduit, and said shaft having a diameter for rotat-v wardly to their expanded positions.

I I! t I =5

Claims

1. A tool for tightening a connector to a conduit said connector including a body member having an externally threaded portion and an integrally formed first nut defining portion and a gland tightening second nut engaging said externally threaded portion, comprising a first relatively stationary chuck member having first jaws movable between advanced contracted and retracted expanded positions respectively, a second chuck member axially spaced from and coaxial with and rotative relative to the first chuck member and having second jaws movable between advanced contracted and retracted expanded positions respectively, jaw closing means for urging said first and second jaws toward their contracted positions when said nuts register with respective jaws, and drive means for rotating said second chuck member.

6. The tool of claim 1 wherein said second chuck is axially movable between a retracted position proximate said first chuck and an advanced position relatively remote from said first chuck, said means for closing said second jaws being responsive to the advance of said second chuck.

11. The tool of claim 10 including a shaft coaxial with said housing and projecting through the rear of said housing and forwardly beyond said first chuck, said drive member being affixed to said shaft.

12. The tool of claim 11 wherein said connector further includes a ferrule for engaging the inner surface of the conduit, and said shaft having a diameter for rotating the ferrule to engage the conduit no later than the tightening of said gland nut.

13. The tool of claim 9 wherein said first chuck includes a pair of transversely spaced blocks having rearwardly converging wells formed therein, said first jaws slidably telescoping said wells and movable forwardly and rearwardly to expanded and contracted positions respectively, spring means urging said jaws rearwardly, and spring means normally urging said second chuck forwardly to bear on said first jaws to urge them forwardly to their expanded positions.