US3913427A

US3913427A - Tool for removing broken threaded fasteners

Info

Publication number: US3913427A
Application number: US474867A
Authority: US
Inventors: George Brase
Original assignee: B AND R TOOL Inc
Current assignee: B AND R TOOL Inc
Priority date: 1974-05-30
Filing date: 1974-05-30
Publication date: 1975-10-21
Anticipated expiration: 1992-10-21
Also published as: JPS50153400A; DE2437142B1; DE2437142A1

Abstract

A tool for removing broken threaded fasteners or studs comprises an open-ended gripping member with an interior wall formed by longitudinal, spaced apart ridge portions adapted to form gripping grooves when driven axially onto a broken threaded fastener. The gripping member is fixed to one end of a threaded shaft that extends through the end wall of a sleeve and is attached at its other end to a flat sided head member. A movable nut is threaded to the shaft between the sleeve and the head member for removing the gripping member from the broken fastener after it has been loosened.

Description

United States Patent [191 Brase 1 Oct. 21, 1975 TOOL FOR REMOVING BROKEN THREADED FASTENERS [75] Inventor: George Brase, Fresno, Calif.

[73] Assignee: B & R Tool, Inc., Fresno, Calif.

[22] Filed: May 30, 1974 [21] Appl. No.: 474,867

5s 40 3o 42 4e 32 f0 Primary ExaminerJames L. Jones, Jr. Attorney, Agent, or Firm-Owen, Wickersham & Erickson [57] ABSTRACT A tool for removing broken threaded fasteners or studs comprises an open-ended gripping member with an interior wall formed by longitudinal, spaced apart ridge portions adapted to form gripping grooves when driven axially onto a broken threaded fastener. The gripping member is fixed to one end of a threaded shaft that extends through the end wall of a sleeve and is attached at its other end to a flat sided head memher. A movable nut is threaded to the shaft between the sleeve and the head member for removing the gripping member from the broken fastener after it has been loosened.

18 Claims, 13 Drawing Figures U.S. Patent Oct. 21, 1975 Sheet 1 of3 3,913,427

FlG 1 TOOL FOR REMOVING BROKEN THREADED FASTENERS This invention relates to a tool for removing threaded studs or fasteners secured to structure and particularly for removing broken cap nuts from truck wheels.

In many instances, threaded studs or other similar fasteners become broken or frozen in place due to corrosion, thereby making their removal from a threaded socket a difficult problem. For example, on vehicles such as large dual wheel trucks the wheels are secured to the axle by cap nuts which have a relatively long threaded shank. Often, during the removal of a wheel for tire repair or replacement the flat sided end portion of one or more of these cap nuts is broken off. Usually, this occurred because the cap nut was firmly lodged in its threaded socket, and in such cases removal of the broken cap nut became a laborious, timeconsuming process. Time lost in attempting to remove such broken fasteners was extremely costly to the truck operation. Previous attempts to remove such cap nuts using conventional tools failed to provide consistent and effective results within a reasonable time.

Accordingly, it is a general object of the present invention to provide a solution to the aforesaid problem and more specifically to provide a tool which will grip a broken or headless threaded cap nut or fastener so that it can be loosened and easily unthreaded from its socket.

Another object of my invention is to provide a tool that can grip and loosen for removal a threaded cap nut or fastener that is broken and headless without damaging its socket and with the application of a relatively small amount of force exerted by an unskilled person of average strength.

Another object of my invention is to provide a tool which will grip a broken threaded stud or cap nut, and

loosen it within its socket, and then will release its grip and separate itself from the stud.

Yet another object of the invention is to provide a tool for removing broken threaded parts from their sockets which is strong, durable and can be readily disassembled for replacement of wearable parts.

Still another object of my invention is to provide a tool for removing threaded parts from their sockets that is particularly well adapted for ease and economy of manufacture.

BRIEF SUMMARY OF THE INVENTION The aforesaid and other objects of my invention are accomplished by a tool comprising an open-ended gripping member having an elongated cavity with an irregular inner wall. Spaced circumferentially around this latter wall are a series of longitudinal ridges having relatively obtuse edges. The gripping member is made of a relatively hard metal so that when driven longitudinally onto a broken stud or cap nut the obtuse edges form gripping grooves extending transversely through its threads. The gripping member is connected to a threaded shaft that extends through the end wall of a sleeve member that surrounds the gripping member. Fixed to the end of the shaft is a flat sided head member such as a hex shaped nut. Threadedly engaged to the shaft between the head member and the end wall of the sleeve member is an adjustable nut which is used for re moving the gripping member from the threaded cap nut after it has been loosened in its socket by the tool. The

tool is put into use by placing the gripping member in line with the threaded fastener to be removed and driving it onto the fastener by striking the head member of the tool. Once the gripping member has been driven into a forced engagement with the threaded member the tool head member is turned by a suitable wrench in theproper direction to loosen the threaded fastener. Once loosened, the adjustable nut on the tool shaft is turned until the gripping member is drawn into the sleeve member and pulled off of the loosened threaded member. The entire loosening and removal process for an otherwise difficult-to-remove fastener can be performed quickly and easily with a relatively small amount of manual skill and strength.

Other objects, advantages and features of my invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing:

BRIEF DESCRIPTIONOF THE DRAWING FIG. 1 is a view in perspective showing a typical hub of a truck axle with projecting cap nuts for securing the inside wheel thereon, one of the cap nuts being broken and thereby requiring removal by a tool according to the present invention;

FIG. 2 is a view in elevation showing a tool embodying the principles of the present invention being driven onto a broken cap nut;

FIG. 3 is a view in section taken along line 33 of FIG. 2;

FIG. 4 is a view similar to FIG. 2 showing the tool in section with its gripping member in place on the broken cap nut;

FIG. 5 is a view in section taken along line 55 of FIG. 4;

FIG. 6 is a view of the tool in FIG. 4 showing the gripping member removed from the cap nut after the latter has been loosened in its socket;

FIG. 7 is a view in elevation and in section of a somewhat modified form of tool embodying the principles of the present invention;

FIG. 8 is a view in section of another modified form of tool according to the invention;

FIG. 8a is a fragmentary view showing a modified form of the tool of FIG. 8;

FIG. 9 is a view in section of yet another modified form of tool according to the invention;

FIG. 9a is a fragmentary view'in section showing a modified head end portion of my tool;

FIG. 10 is an enlarged endview of the tool in FIG. 9 taken along line l010; and

FIG. 11 is another fragmentary view in section showing the head end of a tool according to the invention.

DETAILED DESCRIPTION OF EMBODIMENT Referring to the drawing, FIG. 1 shows the inside wheel 12 of a typical dual wheel truck axle 14 as it appears when ready for removal from the axle hub 16 to which it is secured by a series of cap nuts 18 that extend through holes 20 in the wheel. These cap nuts, which are similar to threaded studs each have a threaded shank portion, one end of which is adjacent to an enlarged beveled collar 22. Extending from the collar is an inner end portion 24 (see FIG. 2) that projects through the wheel 12 and is threadedly seated to a flange portion 25 of the axle hub. The outer end of each cap nut is provided with a flat sided nut-like portion 26 to facilitate being gripped by an appropriate wrench for removal from the axle hub. However, this outer end portion of a cap nut is often broken off due to application of excessive torque, and such a broken cap nut is designated by numeral 18a. The problem of removing this broken cap nut then requires the use of a tool 30 embodying the principles of the present invention.

As shown in greater detail in FIGS. 2-6, the tool 30 comprises a gripping member 32 having a generally cylindrical shape with an elongated cavity 34 that is open at its inner end. The inside wall of the aforesaid cavity has an irregular shape formed by a series of longitudinal notches 36 and ridges 38 that are circumferentially spaced apart. Any suitable number of ridges 38 may be provided depending on the size of the tool and its intended use. For purposes of illustration the tool 30 of FIGS. 2-6 is shown with 12 ridges 38 but, as shown in FIG. 10, it could have eight or some other number, if desired. The ridges have fairly sharply defined edges, and since the gripping member is made from a relatively hard material, such as tool steel, they can readily be driven transversely into interference with and through a series of threads to form grooves 30 through them, as shown in FIG. 5. v

The inner end of the gripping member is axially aligned with and secured to a threaded shaft 40, as by welding, or, as described below, it may be detachable from the shaft. The diameter of the shaft is substantially less than that of the gripping member 32 so that an annular shoulder 42 is formed on it where the shaft joins the gripping member. The main body of the shaft extends through an opening 44 in an inner end portion 46 of a sleeve member 48 whose inside diameter is sufficiently larger than that of the gripping member to form a substantial clearance with it. The outer end of the sleeve member is open and its end edge 50 is preferably in a plane perpendicular to the longitudinal axis of the shaft.

The outer end of the shaft 40 has an enlarged head 52 provided with a series of flat sides, such as a standard hex nut. Adjacent to the inner end of the shaft head and also fixed thereto or to the shaft I may provide a circular flange member 54 whose diameter is substantially greater than the shaft 40. Threadedly engaged with the shaft and movable along it between the flange member and the inner end of the gripping member is a retraction nut 56.

Within the sleeve member 48 and surrounding the shaft 40 in the embodiment of FIGS. 1-6 is a coil spring 58 which is retained under compression by the fact one end engages the inner end wall 46 of the sleeve member 48 and the other end is retained by the shoulder 42 on the gripping member 32. Thus, the spring 58 constantly urges the gripping member outwardly toward the open end of the sleeve member while urging the sleeve end wall 46 against the retraction nut 56.

As shown in FIGS. 2, and 6 the sleeve member 48 and its annular end wall 46 can be fabricated from separate pieces and welded together or they could be machined or otherwise made as an integral component. Alternatively, as shown in FIG. 7, a modified tool a may be provided wherein a separate cap portion 60 is threadedly secured to one end of a tubular member 62 to form a sleeve member 48a. Such a modified tool has some advantages in the simplicity of shape and assembly of its components, but its operation in use is the same as that of tool 30.

When the tool 30 is to be used for removing a broken cap nut 18a, as shown in FIG. 1, it is first aligned with the broken cap nut shank so that the ridge portions 38 of the gripping member 32 are engaged with and slightly interferring the exposed threads of the cap nut (See FIG. 2). At this point, the retraction nut 56 is turned back on the shaft 40 so that the outer end of the gripping member projects outwardly from the inner edge 50 of the sleeve member. Now, a driving force, as by a suitable hammer, is applied to the head 52 of the shaft, and this force causes the ridges 38 of the gripping member 32 to cut across the threads of the cap nut thereby forming a gripping contact with it (See FIG. 4). The distance that the gripping member must be driven onto the broken cap nut 18a to form adequate gripping contact may vary depending on the size of the cap nut and to what degree it is threaded in place. However, I have found that where the ridge portions 38 of the gripping member each provide an interference with the cap nut threads of around l/64 to l/32 inches, a gripping engagement of the ridges of from one-fourth to onehalf inches in length will be sufficient to prevent any slippage between the cap nut and the gripping member. When this contact is made, a suitable wrench can now be applied to the fixed head 52 of the tool to turn it and the broken cap nut in the proper direction of rotation to loosen the latter from its seat. When this has been accomplished, the gripping member is removed from the cap nut by turning the retraction nut on the shaft against the inner end wall of the sleeve member, as shown in FIG. 6. This causes the outer edge 50 of the sleeve member to bear against the surface around the cap nut and pulls the gripping member from it. Once the gripping member is free from the loosened cap nut the tool 30 can be removed and the broken cap nut 18a can be completely removed from its socket by hand.

Another somewhat modified tool 30b embodying the principles of my invention is shown in FIG. 8. In this embodiment, a threaded shaft 40b is attached to a gripping member 32b so that the latter can be disconnected from the shaft and replaced if its gripping ridges 38 become worn. Thus, the shaft 40b has an end portion of reduced diameter which extends through an opening 72 in a central bearing portion 74 of the gripping member 32b. As shown in FIG. 8, the reduced end portion of the shaft is tapped axially to receive the threaded shank of a retaining screw 76 whose head 78 bears against the central bearing portion. Alternatively, as shown in FIG. 8a, the aforesaid retaining screw could be replaced by a stud 80 or an integral threaded portion extending from the end of the shaft, with a nut 82 threaded to the stud which again bears against the central bearing portion 74 of the gripping member. With either arrangement as can be readily seen, the gripping member 32b may be quickly and easily removed from the shaft 40b to disassemble the tool and replace a worn gripping member.

The tool 30b is also provided with a thrust bearing 84 of the conventional ball or roller type friction between the sleeve 48b and a retraction nut 56b when torque is applied to the tool head 52b to loosen a cap nut or the like. On the tool 30b an outer race 86 of the thrust bearing is secured to the main sleeve 48b by a collar 88. The inner race 90 of the bearing is attached by some suitable means to the sleeve adjusting nut 56b. For example, it may be welded thereto, or the nut 56b may be magnetized to such an extent that it holds the inner race closely to it with considerable force. In any event, the nut 56b is essentially attached to the thrust bearing 84 and thus to the sleeve 48b so that, in this embodiment, when the nut is turned on the shaft 40b it also 'moves the main sleeve relative to it. This eliminates the necessity for the spring 58 in tool 30.

Yet another embodiment according to the principles of my invention is shown as a tool 300 in FIG. 9. Here, the tool shaft 400 is preferably attached by a removable fastener 76 to the gripping member 32a in essentially the same way as shown in FIG. 8. It should be noted that the gripping member 32c may be made long enough and with a large enough cavity 92 at itsopen end so that it will fit around even an unbroken cap nut 18. Thus, if the flat sided end 26 of a cap nut gets worn or rounded off by constant use, and ordinary wrenches cannot grip it, my tool 300 can be placed over the worn cap nut to grip it for removal by means of the gripping member 32c.

On the tool 30c the sleeve 480 comprises a central member 94 with external threads and an adjustable inner end portion 96 threadedly attached thereto which enables the sleeve to be extended in length where desired. Threadedly secured to the other end is an outer end portion 98 having a cylindrical recess 100 within which is secured, as by a press fit, the outer race 86 of a thrust bearing 84. The inner race 90 of this bearing may be secured in the same manner as the embodiment of FIG. 8 to a retraction nut 56a, so that rotation of this nut will move the entire sleeve 48c relative to the shaft 400 and again eliminate the need for an internal spring.

In FIG. 9a, another arrangement for connecting a retraction nut 56d to a thrust bearing 84 is shown. Here, the nut is provided with an integral flange portion 102 at one end which is attached to or held against the inner race 90 of the bearing 84 by an outer lip 104 of the outer race 86. The outer race is fixed within a cavity 106 in the main sleeve 48d as by a press fit, as shown in FIG. 9. Again, when the nut 56d is rotated on its shaft 40d it moves the entire sleeve axially relative to the shaft.

In some instances it may become desirable to remove the head member 52 of the tool and replace it if it becomes worn. Although each head member is preferably provided with a convex surface 108 and is made of hardened material, it may become worn after extensive use of the too]. To make removal of the head member simple as shown in FIG. 1, the outer end of the shaft 40 is provided with a series of grooves and splines 110 and this end portion is merely forced within a cylindrical cavity 112 of the head member with an interference fit. The fit is such that no slippage can occur between the head member and the shaft when the head is turned by some torquing device to loosen a cap nut. However, when it becomes necessary to remove a worn head member from the shaft, the retraction nut 56 is turned on the shaft so as to move it against the head member.

' An annular extended portion 114 on the nut 56 bears against the head member and pushes it axially until it is free of the shaft.

From the foregoing it should be apparent that the present invention provides an effective solution to the heretofore vexing problem of removing broken or worn cap nuts. While my tool has a particular application to broken cap nuts it is obvious that it could also be applied to other situations where other threaded fasteners such as studs must be loosened for removal from their sockets in various types of structure. The tool provided is' easy to operate by unskilled labor so a large amount of valuable time is saved in removing broken or worn fasteners. Although it can be made strong and durable, itican also be quickly disassembled when worn parts suchas the gripping member and the head member require replacement. i

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

1. A tool for loosening a broken or worn threaded fastener within its socket in a structural member to facilitate removal therefrom comprising:

an elongated shaft having at least one threaded portion thereon; i

a head member attached to an outer end of said shaft so as to transmit torque to it when said head member is turned;

a gripping member attached to an inner end of said shaft, said gripping member having an open ended, axially extending cavity and means on the inner walls of said cavity for gripping the threaded portion of a fastener to be loosened; and

means engaging said threaded portion on said shaft and bearing against said structural member for removing said gripping member from a fastener after it has been loosened.

2. The tool as described in claim 1 wherein said gripping member comprises an elongated body, and said means on its inner walls comprises a series of longitudinally extending, parallel ridges spaced apart by recesses and adapted to interfere with and form grooves transversely through the fastener to be loosened when said tool is driven axially onto said fastener.

3. The tool as described in claim 2 wherein said ridges and recesses are formed by flat intersecting surfaces so that the inner ends of said ridges terminate with relatively sharp well defined edges that are parallel to the longitudinal axis of said tool and said gripping member.

4. The tool as described in claim 2 wherein said ridges and recesses terminate at a point spaced inwardly from the outer edge of said gripping member and said cavity thereof extends inwardly from the inner ends of said ridges so that the tool is useable for either long or short fasteners that require loosening.

5. The tool as described in claim 1 wherein said gripping member has a bearing portion and said shaft has an end portion of reduced diameter which extends through said bearing portion, and screw means in the end of said shaft for removably connecting said shaft to said bearing portion of said gripping member.

6. The tool as described in claim 1 wherein said head member comprises a hex shaped member having a convex top surface.

7. The tool as described in claim 1 wherein said head member comprises a flat sided member having a cylindrical recess, and the outer end of said shaft has spline portions which form an interference fit with the inner wall of said cylindrical recess.

8. The tool as described in claim 1 wherein said means engaging the threaded portion on said shaft for removing said gripping member comprises:

a main sleeve member surrounding said shaft and having a larger inside diameter than the outside diameter of said gripping member and an annular end wall around said shaft;

21 retraction nut threadedly engaged to said shaft between said annular end wall of said sleeve member and said head member.

9. The tool as described in claim 8 and coil spring means within said sleeve member extending between its said annular end wall and the inner end of said gripping member.

10. The tool as described in claim 8 including means connecting said annular end wall of said sleeve member to said retraction nut.

11. The tool as described in claim 10 wherein said means connecting said annular end wall to said retraction nut comprises a thrust bearing having an inner race and an outer race and a plurality of bearing members between said races.

12. The tool as described in claim 11 wherein said outer race of said thrust bearing is fixed to the inner end of said sleeve member.

13. The tool as described in claim 12 wherein said retraction nut has a flange portion at one end and the outer race of said thrust bearing has lip means extending partially around said flange portion.

14. The tool as described in claim 12 wherein said retraction nut is magnetized so as to be magnetically attracted to said thrust bearing.

15. The tool as described in claim 12 wherein said retraction nut has an extended collar portion for engaging said head member to move it axially on said shaft and thereby cause its removal when desired.

16. A tool for loosening a broken or worn threaded fastener within its socket for removal therefrom comprising:

an elongated shaft having at least one threaded portion thereon;

a gripping member attached to an inner end of said shaft, said gripping member having an open ended, axially extending cavity and spaced apart, axially extending ridge members on the inner walls of said cavity for gripping the threaded portion of a fastener to be loosened;

a movable sleeve means extending axially around said shaft and said gripping member and having an inner head end surrounding said threaded shaft portion; 1

a retraction nut on said threaded shaft portion for exerting an axial force against said inner head end of said sleeve means when the other end of said sleeve means is against structure surrounding a fastener that has been loosened, thereby removing said gripping member from the fastener.

17. The tool as described in claim 16 including a thrust bearing between said inner head end of said sleeve means and said retraction nut.

18. The tool as described in claim 16 wherein said retraction nut has an integral flange, and a thrust bearing between said flange and said inner head end of said sleeve means, said thrust bearing having an outer race with annular lip means secured to said retraction nut flange.

Claims

1. A tool for loosening a broken or worn threaded fastener within its socket in a structural member to facilitate removal therefrom comprising: an elongated shaft having at least one threaded portion thereon; a head member attached to an outer end of said shaft so as to transmit torque to it when said head member is turned; a gripping member attached to an inner end of said shaft, said gripping member having an open ended, axially extending cavity and means on the inner walls of said cavity for gripping the threaded portion of a fastener to be loosened; and means engaging said threaded portion on said shaft and bearing against said structural member for removing said gripping member from a fastener after it has been loosened.

8. The tool as described in claim 1 wherein said means engaging the threaded portion on said shaft for removing said gripping member comprises: a main sleeve member surrounding said shaft and having a larger inside diameter than the outside diameter of said gripping member and an annular end wall around said shaft; a retraction nut threadedly engaged to said shaft between said annular end wall of said sleeve member and said head member.

16. A tool for loosening a broken or worn threaded fastener within its socket for removal therefrom comprising: an elongated shaft having at least one threaded portion thereon; a head member attached to an outer end of said shaft so as to transmit torque to it when said head member is turned; a gripping member attached to an inner end of said shaft, said gripping member having an open ended, axially extending cavity and spaced apart, axially extending ridge members on the inner walls of said cavity for gripping the threaded portion of a fastener to be loosened; a movable sleeve means extending axially around said shaft and said gripping member and having an inner head end surrounding said threaded shaft portion; a retraction nut on said threaded shaft portion for exerting an axial force agAinst said inner head end of said sleeve means when the other end of said sleeve means is against structure surrounding a fastener that has been loosened, thereby removing said gripping member from the fastener.