APPARATUS FOR MOUNTING TENSION INDICATORS
United States Patent 3729988
In an apparatus or device for use with a tool for tightening fastener elements such as bolts, nuts, screws and the like, a socket is rotatably mounted in a housing for receipt of one element of the threaded fastening joint such as the bolt, screw or nut. A guide in the housing positions the tab in alignment with the socket and fastening element so that when the joint is tightened, the tab is compressed between two bearing surfaces in the joint. The tab is comprised of a plastic strip having a current conducting wire embedded along each edge which wires are connected in an electric circuitry mounted in the housing. When the joint has been loaded in tension a predetermined amount, the plastic tab partially deforms and extrudes to establish electrical continuity between the joint and wires to close the circuit thereby signalling pre-load. Further tightening of the joint completely shears the plastic tab and wires to signal that minimum proof load has been reached. A magazine or reel is mounted in the housing to permit continuous and automatic loading of a plurality of tabs collated into a continuous strip. The electric signal can inform the operator or control the tool when the indicated loads are reached.
US Patent References:
INDICATING MEANS
Rogers - February 1970 - 3495907
Transducer
Bodner et al. - August 1961 - 2998585
Fastener rotating and feeding device
Reynolds - March 1959 - 2878700
Method and machine for assembling washers with rotary fasteners
Stern - September 1955 - 2716762
Article-assembling apparatus
Lubbert - June 1954 - 2681668
INDICATING MEANS
Rogers - February 1970 - 3495907
Transducer
Bodner et al. - August 1961 - 2998585
Fastener rotating and feeding device
Reynolds - March 1959 - 2878700
Method and machine for assembling washers with rotary fasteners
Stern - September 1955 - 2716762
Article-assembling apparatus
Lubbert - June 1954 - 2681668
Application Number:
05/084991
Publication Date:
05/01/1973
Filing Date:
10/29/1970
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
470/3, 81/57.370
International Classes:
G01L5/24; G01L5/24
Field of Search:
10/155R,155A 29/23D,23TS,208,211 81/57.37,57.23,52.4R,52.5,57.38 815/62 340/213 73/88F
US Patent References:
| 2642592 | Method and machine for assembling washers with fasteners | June 1953 | Nielsen |
Primary Examiner:
Queisser, Richard C.
Assistant Examiner:
Korkosz, Arthur E.
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows
1. Apparatus for feeding a tension indicating tab means and rotatable fastener element into a threaded fastener joint and tightening said fastener element to tension said joint comprising, in combination: a housing having a surface engageable with said joint, said surface having means defining an opening to permit passage of said fastener element and tab means through said opening into engagement with said joint; a socket mounted within said housing for receiving said fastener element, said socket being rotatable to rotate and advance said fastener element through said opening into said joint; and guide means in said housing for receiving and positioning said tab means intermediate said joint and fastener element so that when said socket is rotated to advance said fastener element, said fastener element and tab means are advanced through said opening in said surface and tensioned with said joint.
2. Apparatus according to claim 1 wherein said combination further includes electrical circuitry and signal means mounted in said housing and operatively associated with said tab means, said tab means including electrical conducting means connected to said electrical circuitry and signal means, the latter being open until said fastener element reaches a predetermined tensile load, whereupon said electrical circuitry is closed and said signal means is activated to indicate a predetermined tensile load in said joint when said socket is rotated to tighten said fastener element and tab means.
3. Apparatus according to claim 2 wherein said housing includes magazine means for storing a plurality of tab means, said magazine means being connected to said guide means to feed said tab means intermediate said joint engaging said flat surface and said socket.
4. Apparatus according to claim 3 wherein said magazine means is comprised of a rotatable reel about which said tab means is wound, the hub of said reel having a pair of lead wires interconnected to said electrical circuitry and signal means, said lead wires extending from said hub for connection to said tab means.
5. Apparatus according to claim 1 wherein said surface is flat and said socket is mounted within said housing above said flat surface, said guide means being adjacent said flat surface intermediate said flat surface and socket, said guide means defining a relatively flat guide track for receiving and positioning said tab means intermediate said joint and fastener element.
6. Apparatus according to claim 1 wherein said housing includes a base and upper portion adjustable for relative movement therebetween, said base including said flat surface and guide means, said upper portion including said socket, said upper portion when moved toward said base portion acting to position said fastener element and tab means beyond said flat surface into said joint for rotation of said socket to tension said joint.
7. An apparatus for mounting a tensioning indicating tab means and threaded fastener element in a fastener joint and tensioning said joint comprising in combination: a plurality of tab means of flowable material having means of substantially greater hardness than said material embedded along each edge of said tab means; a housing having a surface engageable with said joint; a socket mounted within said housing for receiving said fastener element, said socket being rotatable to rotate and advance said threaded fastener element into said joint beyond said surface; and guide means in said housing for receiving and positioning said tab means intermediate said joint and fastener element.
8. The apparatus according to claim 7 wherein said combination further includes electrical circuitry and signal means mounted in said housing, said means of substantially greater hardness in said tab means being comprised of malleable electric conducting wire connected to said electrical circuitry and signal means, said fastener element being comprised of electrical conducting material initially shielded from said malleable conducting wire in said tab means so that when said fastener element and tab are initially tightened to tension said joint said electrical circuitry means is open, and after said joint is tensioned to a predetermined load, said flowable material is deformed between said electrical wire and fastener element so that said electrical circuitry is closed thereby actuating said signal means to indicate when said tension joint is at said predetermined load.
9. Apparatus according to claim 8 wherein a second predetermined tensile load of greater magnitude than said first load is indicated by said electrical circuitry and signal means when said malleable electrical wire is severed to reopen said electrical circuitry when said second predetermined tensile load is reached.
10. Apparatus according to claim 8 wherein said housing includes a magazine means for storing said plurality of tab means, said magazine means being connected to said guide means to feed said tab means intermediate said joint engaging flat surface and said socket.
11. Apparatus according to claim 10 wherein said plurality of tab means are interconnected to form a strip of arbitrary length, said electrical circuitry and signal means being connected to said malleable wires at the end of said strip.
12. Apparatus according to claim 11 wherein said magazine is comprised of a rotatable reel about which said tab strip is wound, the hub of said reel having a pair of lead wires interconnected to said electrical circuitry and signal means, said lead wires extending from said hub for connection to said strip of tab means.
13. Apparatus according to claim 7 wherein said surface is flat and said socket is mounted within said housing above said flat surface, said guide means being adjacent said flat surface intermediate said flat surface and socket, said guide means defining a relatively flat guide track for receiving and positioning said tab means intermediate said joint and fastener element.
1. Apparatus for feeding a tension indicating tab means and rotatable fastener element into a threaded fastener joint and tightening said fastener element to tension said joint comprising, in combination: a housing having a surface engageable with said joint, said surface having means defining an opening to permit passage of said fastener element and tab means through said opening into engagement with said joint; a socket mounted within said housing for receiving said fastener element, said socket being rotatable to rotate and advance said fastener element through said opening into said joint; and guide means in said housing for receiving and positioning said tab means intermediate said joint and fastener element so that when said socket is rotated to advance said fastener element, said fastener element and tab means are advanced through said opening in said surface and tensioned with said joint.
2. Apparatus according to claim 1 wherein said combination further includes electrical circuitry and signal means mounted in said housing and operatively associated with said tab means, said tab means including electrical conducting means connected to said electrical circuitry and signal means, the latter being open until said fastener element reaches a predetermined tensile load, whereupon said electrical circuitry is closed and said signal means is activated to indicate a predetermined tensile load in said joint when said socket is rotated to tighten said fastener element and tab means.
3. Apparatus according to claim 2 wherein said housing includes magazine means for storing a plurality of tab means, said magazine means being connected to said guide means to feed said tab means intermediate said joint engaging said flat surface and said socket.
4. Apparatus according to claim 3 wherein said magazine means is comprised of a rotatable reel about which said tab means is wound, the hub of said reel having a pair of lead wires interconnected to said electrical circuitry and signal means, said lead wires extending from said hub for connection to said tab means.
5. Apparatus according to claim 1 wherein said surface is flat and said socket is mounted within said housing above said flat surface, said guide means being adjacent said flat surface intermediate said flat surface and socket, said guide means defining a relatively flat guide track for receiving and positioning said tab means intermediate said joint and fastener element.
6. Apparatus according to claim 1 wherein said housing includes a base and upper portion adjustable for relative movement therebetween, said base including said flat surface and guide means, said upper portion including said socket, said upper portion when moved toward said base portion acting to position said fastener element and tab means beyond said flat surface into said joint for rotation of said socket to tension said joint.
7. An apparatus for mounting a tensioning indicating tab means and threaded fastener element in a fastener joint and tensioning said joint comprising in combination: a plurality of tab means of flowable material having means of substantially greater hardness than said material embedded along each edge of said tab means; a housing having a surface engageable with said joint; a socket mounted within said housing for receiving said fastener element, said socket being rotatable to rotate and advance said threaded fastener element into said joint beyond said surface; and guide means in said housing for receiving and positioning said tab means intermediate said joint and fastener element.
8. The apparatus according to claim 7 wherein said combination further includes electrical circuitry and signal means mounted in said housing, said means of substantially greater hardness in said tab means being comprised of malleable electric conducting wire connected to said electrical circuitry and signal means, said fastener element being comprised of electrical conducting material initially shielded from said malleable conducting wire in said tab means so that when said fastener element and tab are initially tightened to tension said joint said electrical circuitry means is open, and after said joint is tensioned to a predetermined load, said flowable material is deformed between said electrical wire and fastener element so that said electrical circuitry is closed thereby actuating said signal means to indicate when said tension joint is at said predetermined load.
9. Apparatus according to claim 8 wherein a second predetermined tensile load of greater magnitude than said first load is indicated by said electrical circuitry and signal means when said malleable electrical wire is severed to reopen said electrical circuitry when said second predetermined tensile load is reached.
10. Apparatus according to claim 8 wherein said housing includes a magazine means for storing said plurality of tab means, said magazine means being connected to said guide means to feed said tab means intermediate said joint engaging flat surface and said socket.
11. Apparatus according to claim 10 wherein said plurality of tab means are interconnected to form a strip of arbitrary length, said electrical circuitry and signal means being connected to said malleable wires at the end of said strip.
12. Apparatus according to claim 11 wherein said magazine is comprised of a rotatable reel about which said tab strip is wound, the hub of said reel having a pair of lead wires interconnected to said electrical circuitry and signal means, said lead wires extending from said hub for connection to said strip of tab means.
13. Apparatus according to claim 7 wherein said surface is flat and said socket is mounted within said housing above said flat surface, said guide means being adjacent said flat surface intermediate said flat surface and socket, said guide means defining a relatively flat guide track for receiving and positioning said tab means intermediate said joint and fastener element.
Description:
BACKGROUND OF INVENTION
This invention relates to a tension indicating system and, more particularly, to a power tool that will run the fastener to a first position and indicate pre-load; and further rotate the fastener into the plastic range and indicate minimum proof load.
In copending application entitled METHOD AND MEANS FOR INDICATING TENSION, filed Oct. 19, 1970, Ser. No. 81,819, which application is incorporated herein by reference, the invention deals with a tension indicating tab which would indicate visually or through an electric signal when pre-load had been reached in a threaded joint and when minimum proof load had been reached. The invention has several distinct advantages over the prior and existing art in that it is more accurate and reliable and was a function of load tension rather than torque. In addition, the tab material provided a locking bond in the joint so that if the joint became loosened, the joint would still not rotate. Furthermore, the material acted as a sealant to weatherproof the joint and due to its lubricating tendencies, reduced the amount of torque up to 50 percent necessary to properly tighten the join to minimum proof load.
SUMMARY OF INVENTION
It is a principal object of this invention to provide various power tools capable of operating at various r.p.m.'s that will run the fastener to a snug pre-load position, indicate that pre-load has been achieved, and further rotate the fastener up to minimum proof load indicating when proof load has been achieved.
It is another principal object of this invention to provide a variety of tools which will feed a collated strip of tabs in various fastener joints from a reel or magazine either manually or automatically to increase the accuracy, production, and speed while reducing installation costs.
Yet another object of this invention is to provide a tool which will be automatically shut off at pre-load and minimum proof load.
For achievement of these and other objects, an adapter tool housing is provided having socket means rotatably mounted therein, and adapted for attachment to manual or power operating means to drive the socket. The adapter includes a guide track means for inserting a single tension indicating tab or collated strip in a work engaging position, the tab having a cutout portion to permit a threaded bolt to pass therethrough, and metallic means embedded along each edge of the tab forming leads connectable to an electric circuit mounted in the adapter having an electrical source and signal means so that when the electric circuit is closed, the signal is actuated. When the socket and indicating tab are positioned for tightening of the joint, and the joint is tightened to a predetermined tensile load, tab material disposed between the bearing surfaces is deformed or extruded sufficiently to establish electrical continuity between the metallic means and joint, thereby closing the circuit to actuate the electrical signal means thus indicating pre-load. Further tightening of the joint causes the tab material and wires to become completely deformed, extruded and sheared from between the bearing surfaces thereby breaking the lead wires to close the electrical circuit causing the electrical signal means to cease thereby indicating minimum proof load in the joint.
Various electrical circuitry can be mounted in the adapter so that if a power source is used in tightening the joint, the power source can be stopped at pre-load and/or minimum proof load and/or the collated strip can be automatically fed so that the next tension indicating tab is properly positioned after the last operation.
By providing an adapter tool which not only indicates pre-load and minimum proof load in the joint but provides for a continuous supply of indicating tabs, significant accuracy, reliability and economical installation cost reduction is achieved.
DESCRIPTION OF THE DRAWINGS
A better understanding of this invention will be found by the following description thereof made in conjunction with the drawings wherein:
FIG. 1 is a cutaway side view of a reel fed adapter tool provided by this invention;
FIG. 2 is an end view of the adapter shown in FIG. 1 taken in cross section along line II--II of FIG. 1;
FIG. 3 is a bottom view of the apparatus shown in FIGS. 1 and 2;
FIG. 4 is a cutaway side view of an alternative embodiment for feeding a collated strip of tension indicating tabs;
FIG. 5 is a bottom view of the embodiment shown in FIG. 4 taken in cross section along line V--V of FIG. 4;
FIG. 6 is an end view of the apparatus shown in FIGS. 4 and 5;
FIG. 7 is a side view in cross section of an alternative embodiment; and
FIG. 8 is a plan view of one type of tension indicating strip for use in the alternative shown in FIGS. 4-7 for continuous feeding.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings in detail, FIGS. 1-3 show a reel-type loader 10 having a main body or housing portion 12 with a reel 14 rotatably mounted at one end of the body for storing a roll or strip 16 comprised of a plurality of collated tension indicating tabs as described in the above identified copending application, Ser. No. 81,819 entitled MEANS FOR INDICATING TENSION and filed Oct. 19, 1970. Such strip as best shown in FIG. 3 is a construction of plastic material having a plurality of openings 15 for receiving bolts and wires 17 and 19 embedded therein on each side of the openings and extending the entire length of the strip so as to provide an electrical circuit open at both ends. Strip 16 is wound onto the reel so that when the reel is positioned in body 12 and rotated in a clockwise direction, the strip is fed along the bottom portion 18 of body 12 through a guide 20 which prevents the strip from lifting up off bottom 18 of the body into the socket portion 22 of the adapter.
Socket portion 22 is comprised of a conventional socket 24 held within the body by a frame 26 which encloses the socket, frame 26 preferably being characterized as a spring clamp which closes around the socket but permits rotation of socket 24 in the frame. With frame 26 in the form of a spring clamp, the socket is interchangeable in adapter tool 10 so that different size joints can be tightened with the same reel adapter. Socket 24 shown in FIG. 1 has a lower portion 34 characterized by a hexigonal socket for receipt of a hex nut 36. The upper portion 28 of socket 24 has a standard square opening 30 permitting insertion of a conventional adapter tool 50 such as a hand wrench or power drill with an adapter plug 32.
The signal indicating means is provided by a battery 40 and light 42 mounted in hub portion 44 of the reel. Leads 17 and 19 projecting from the inner end of strip 16 are connected to hub 44 by a pair of set screws 43 and 45 which in turn connect the battery and light in series by a plurality of wires 47, 49 and 51. thus, an open circuit is provided which includes one wire 17 of strip 16, wire 47 connected between wire 17 of strip 16 and one terminal of battery 40; wire 49 connected between battery 40 and one terminal of the light 42; wire 51 connected between the other terminal of light 42 and the other wire 19 of strip 16. The circuit is open at the extreme free end of the strip 16. Thus, shorting across the two wires 17 and 19 of strip 16 closes the circuit energizing the light 42 and creating a signal.
It should be evident that the circuit can be closed by bridging the two wires 17 and 19 of strip 16 by means of a nut contacting the two during the fastening of said nut on a bolt or other threaded member. Thus, as described in my copending application, when a threaded joint is loaded in tension to pre-load (pre-load being the predetermined load wherein the plastic material of the tension indicating tab is partially extruded so that electrical continuity is established between the joint or hex nut 36 and the edge wires in the tab) the electrical circuit is closed and the light indicates the pre-load has been established. Such signal indicates to the operator that pre-load has been reached.
While the battery 40 and light 42 are shown mounted on an internal plate 46 in FIG. 2, it will be appreciated that various arrangements for mounting the light, battery, and wire connectors are envisioned.
OPERATION
To operate the reel-type loader 10 shown in FIGS. 1-3, a hex nut 36 is inserted in socket 24; reel 14 is manually or mechanically rotated clockwise to bring the innermost indicator tab of the strip into alignment with hex nut 36 as shown in FIGS. 1 and 3 so that the adapter tool 50 can be positioned on a fastener joint (not shown). At this point, adapter tool 50 such as an electrical drill having a plug adapter 32 for insertion into socket 24 is mounted to drive the socket. It will be appreciated that a mechanical wrench could be used in lieu of a power tool. Tool 50 is then activated to rotate socket 24 and tighten hex nut 36 onto the fastener joint. When pre-load is reached, sufficient deformation or extrusion of the tension indicating tab 16 in the work position will occur resulting in electrical continuity being established between the tab wires 17 and 19 and the joint (not shown) to close the electrical circuit operated by battery 40 thereby turning on light 42. This alerts the operator or tool that pre-load has been reached.
Once pre-load has been reached, further operation of tool 50 will increase the tensile load in the joint until the tab indicating wires 17 and 19 and material are completely sheared from between the hex nut 36 and joint bearing surface closing the electrical circuit to turn off light 42 and alert the operator or tool that minimum proof load has been reached. At this point, further operation of tool 50 should be terminated as the joint is secure. Further rotation past this point may tend to stretch the joint past its ultimate breaking point. For a more detailed description of the operation of the tension indicating tab or strip material 16, reference is made to the above identified copending application.
In lieu of manual shut off of tool 10, a circuit similar to that described in reference to FIG. 12 of the above referred to copending application could be used to automatically shut the tool off at pre-load and minimum proof load.
Once a particular joint has been secured, there is a total severance of the strip 16 so that the adapter tool 10 can be removed from the joint by lifting straight up until the hex nut 36 is clear of socket 38 at which point a new hex nut is inserted in the socket; reel 14 is rotated in a clockwise direction until the next operative tab is in position as shown in FIG. 3 and the adapter tool is then placed on the next joint to be fastened.
FIRST ALTERNATIVE EMBODIMENT
Referring now in detail to FIGS. 4-6 and 8, an injector type tool 65 is shown having a base 66 and upper portion 68. The tool is designed to supply a plurality of insertible screws or bolts 70 and a tension indicating strip 72 having a plurality of tabs 74; inject an individual screw 70 through an individual tab into the joint for tightening. In addition, the tool is designed to indicate to the operator or tool when pre-load and minimum proof load has been reached in the joint.
Referring to FIG. 4, two guide tracks 76 and 78 are aligned longitudinally in the lower or base portion 66 and spaced vertically with respect to each other. The upper guide track 76 is provided for receipt of screws 70 while the lower guide track 78 holds and guides the indicating strip 72. The base 66 is adjustably connected to the upper portion 68 by a pair of threaded bolts 79 (only one of which is shown in FIG. 4) mounted through upper portion 68 and through a pair of spaced slots 80 formed in the base so that the base is movable towards and away from the upper portion. The central portion of the base and upper portion are formed to provide an opening 81 to facilitate handling of the tool.
A plurality of screws 70 are inserted into guide track 76 through the open end 83 of the tool and a strip 72 is inserted into the lower guide track 78. Referring to FIG. 6, guide track 76 is preferably C-shaped in cross section to permit insertion of the screws 70 in the opening of the track and directionally guide them into alignment above the tabs 74. On the other hand, the lower guide track 78 is generally rectangular in cross section to act simply as an enclosed guide to directionally control strip 72 into alignment below the screws.
The electrical signal means in tool 65 (FIG. 5) includes a battery 84 and buzzer 85 mounted in the upper portion 68 and connected in series by a plurality of wires 86, 87 and 88 to a pair of fixed terminals 89 and 90, mounted in the base portion 66. Terminals 89 and 90 are rigidly mounted for cooperation with strip 72 shown more clearly in FIG. 8. The strip 72 shown in FIG. 8 includes a plurality of tension indicating tabs 74, but in addition, has a sawtooth configuration along its edges comprising a plurality of notches 122 cut laterally into the strip deep enough in penetration to expose a portion of wires 124 and 126 embedded along each edge of the strip.
The complete electrical circuitry of the signal means is thus established. With strip 72 inserted in the lower guide track 78, it is positioned as shown in FIG. 5 in alignment with screws 70. The exposed ends of the embedded wires 124 and 126 are in electrical contact with terminals 89 and 90. Terminals 89 and 90 are in turn connected to wires 87 and 88 respectively wire 88 being connected to one terminal of the battery while wire 87 is connected to one terminal of the buzzer. Wire 86 interconnects the other terminals respectively of the battery and buzzer. Prior to pre-load, with the circuit connected as described, the circuit is open and the buzzer is not activated. However, when the joint is tightened to pre-load so that electrical continuity is established between wires 124 and 126 of the strip, the circuit becomes closed and the battery actuates the buzzer. Further tightening to minimum proof load severs wires 124 and 126 to turn the buzzer off indicating to the operator of the tool that proof load has been reached. After severance, a portion of wires 124 and 126 extend out from the next tab in the strip at or near the sawtooth notch 122 which exposed ends abut against terminals 89 and 90 when the strip is advanced thereby again establishing the electrical circuit described above for the next joint.
In order to position one of screws 70 in the joint, the row of screws are advanced manually or otherwise along guide track 76 until the innermost screw (screw 70a in FIG. 4) slips off the inner end 91 of guide track 76 into passageway 93. Preferably guide track 76 has a diminishing cross-sectional C-opening at passageway 93 so that there is frictional resistance to screw 70a accidentally entering the passageway unless it is purposefully moved into it. Passageway 93 is dimensionally shaped to permit the screw to move longitudinally within the passageway but not become blocked or caught in it. The passageway passes through the entire body of the adapter tool, having one opening 95 at the top of the tool through the upper portion 68 and a lower opening 97 opening up into guide track 78 so that the tension indicating strip 72 can be positioned and aligned beneath passageway 93 so that an individual tab is aligned with the passageway. A wrench fitting 99 removably fits into passageway 93, fitting 99 having a socket 101 on one end thereof for engagement with the screw head and a plug fitting 103 on the opposite end for engagement with a power tool or hand wrench for rotation of fitting 99.
OPERATION
To operate adapter tool 65, a plurality of screws 70 are inserted in guide track 76 to load the tool. In addition, a tension indicating strip 72 is inserted in guide track 78, the strip having a plurality of tabs 74. The strip 72 is inserted until the innermost end abuts against terminals 89 and 90 which terminals contact wires 124 and 126 embedded in strip 72. This aligns opening 128 with passageway 93 so that when the screws 70 are advanced to deposited screw 70a into the passageway, the screw will pass through the tab opening 128 into the joint as shown in FIG. 4. At this point wrench fitting 99 is inserted into passageway 93 with the socket 101 fitting over the head of screw 70a. A manual or power wrench is then mounted over plug 103 and the screw is rotated. At pre-load, the plastic strip deforms to close the electric circuit by establishing continuity between wires 124 and 126 activating buzzer 85 and at minimum proof load the entire strip is severed to extinguish the buzzer therefore alerting the operator when both pre-load and proof load have been reached. Again, many electrical and mechanical variations are available to achieve various signalling, controlling and loading embodiments.
SECOND ALTERNATIVE EMBODIMENT
Referring now to FIGS. 7 and 8 in detail, FIG. 7 shows an adapter tool 100 for inserting a strip 72 identical to that shown in FIG. 8 and described in reference to the first alternative embodiment of FIGS. 4-6. Tool 100 includes a socket 106, the socket preferably being removable from the tool to permit various size sockets to be inserted in the tool. A standard square opening 108 is exposed on the upper side of the tool to permit insertion of a mechanical wrench or power tool, the socket being rotatably mounted within the adapter. A guide track 105 is provided for insertion of strip 72 so tat one of the tabs 74 can be aligned with the socket to position the tab between the nut inserted in the socket and fastener surface 110. A rotatable cam lock 112 is provided so that when strip 102 is inserted into the guide track, the cam lock is pivoted down onto the strip to lock it into position.
A signal means 114 includes a battery 116; a buzzer 118; a plurality of wires 130, 132, and 134; and a pair of clips 138 (only one of which is shown in FIG. 7). Clips 138 are mounted on the side of tool 100 so that when a tab is properly aligned below the socket, clips 138 are in electrical contact with the exposed portions of wires 124 and 126 embedded in the strip at notches 122. Wire 132 connects one of the clips to a terminal of buzzer 118; wire 130 connects the other terminal of buzzer 118 to a terminal of battery 116; and wire 134 connects the other terminal of battery 116 to the other clip 138. Thus, the identical open circuit is established as hereinbefore described with regards to the first two alternative embodiments and upon pre-load, the embedded wires 124 and 126 are shorted to activate buzzer 118; while at minimum proof load, the circuit is severed to alert the operator or tool at both pre-selected loads.
While adapter tool 100 is shown in FIG. 7 as holding a tension indicating strip 72 comprised of two indicating tabs 74, by shortening guide track 105 to the right of socket 106, the adapter can be designed for single tension indicating tab inserts where desired.
OPERATION
To operate, a nut is inserted in socket 106 and a tab is aligned beneath it for compression between the nut and fastener surface 110. With the tool positioned over the joint and a wrench or power tool inserted into the socket, the joint is tightened. At pre-load, electrical continuity is established between leads 124 and 126 and the circuit through the clips 138, battery 116 and buzzer 118 is closed. Further tightening to proof load shears the lead wires 124 and 126 opening the circuit shutting off the buzzer to indicate proof load. Again, it will be appreciated that various circuitry can be used in combination with the power tool to automatically turn the tool off at pre-load and/or proof load.
Thus, various modified adapter tools are envisioned for automatically or manually advancing a continuous tension indicating strip to reduce installation time and costs, while at the same time providing a consistent quality controlled joint.
It will be obvious to those having ordinary skill in this art that the details of construction of the particular preferred embodiments may be modified in a great many ways without departing from the unique concepts presented. It is therefore intended that the invention is limited only by the scope of the appended claims rather than by particular details of construction shown, except as specifically stated in the claims.
This invention relates to a tension indicating system and, more particularly, to a power tool that will run the fastener to a first position and indicate pre-load; and further rotate the fastener into the plastic range and indicate minimum proof load.
In copending application entitled METHOD AND MEANS FOR INDICATING TENSION, filed Oct. 19, 1970, Ser. No. 81,819, which application is incorporated herein by reference, the invention deals with a tension indicating tab which would indicate visually or through an electric signal when pre-load had been reached in a threaded joint and when minimum proof load had been reached. The invention has several distinct advantages over the prior and existing art in that it is more accurate and reliable and was a function of load tension rather than torque. In addition, the tab material provided a locking bond in the joint so that if the joint became loosened, the joint would still not rotate. Furthermore, the material acted as a sealant to weatherproof the joint and due to its lubricating tendencies, reduced the amount of torque up to 50 percent necessary to properly tighten the join to minimum proof load.
SUMMARY OF INVENTION
It is a principal object of this invention to provide various power tools capable of operating at various r.p.m.'s that will run the fastener to a snug pre-load position, indicate that pre-load has been achieved, and further rotate the fastener up to minimum proof load indicating when proof load has been achieved.
It is another principal object of this invention to provide a variety of tools which will feed a collated strip of tabs in various fastener joints from a reel or magazine either manually or automatically to increase the accuracy, production, and speed while reducing installation costs.
Yet another object of this invention is to provide a tool which will be automatically shut off at pre-load and minimum proof load.
For achievement of these and other objects, an adapter tool housing is provided having socket means rotatably mounted therein, and adapted for attachment to manual or power operating means to drive the socket. The adapter includes a guide track means for inserting a single tension indicating tab or collated strip in a work engaging position, the tab having a cutout portion to permit a threaded bolt to pass therethrough, and metallic means embedded along each edge of the tab forming leads connectable to an electric circuit mounted in the adapter having an electrical source and signal means so that when the electric circuit is closed, the signal is actuated. When the socket and indicating tab are positioned for tightening of the joint, and the joint is tightened to a predetermined tensile load, tab material disposed between the bearing surfaces is deformed or extruded sufficiently to establish electrical continuity between the metallic means and joint, thereby closing the circuit to actuate the electrical signal means thus indicating pre-load. Further tightening of the joint causes the tab material and wires to become completely deformed, extruded and sheared from between the bearing surfaces thereby breaking the lead wires to close the electrical circuit causing the electrical signal means to cease thereby indicating minimum proof load in the joint.
Various electrical circuitry can be mounted in the adapter so that if a power source is used in tightening the joint, the power source can be stopped at pre-load and/or minimum proof load and/or the collated strip can be automatically fed so that the next tension indicating tab is properly positioned after the last operation.
By providing an adapter tool which not only indicates pre-load and minimum proof load in the joint but provides for a continuous supply of indicating tabs, significant accuracy, reliability and economical installation cost reduction is achieved.
DESCRIPTION OF THE DRAWINGS
A better understanding of this invention will be found by the following description thereof made in conjunction with the drawings wherein:
FIG. 1 is a cutaway side view of a reel fed adapter tool provided by this invention;
FIG. 2 is an end view of the adapter shown in FIG. 1 taken in cross section along line II--II of FIG. 1;
FIG. 3 is a bottom view of the apparatus shown in FIGS. 1 and 2;
FIG. 4 is a cutaway side view of an alternative embodiment for feeding a collated strip of tension indicating tabs;
FIG. 5 is a bottom view of the embodiment shown in FIG. 4 taken in cross section along line V--V of FIG. 4;
FIG. 6 is an end view of the apparatus shown in FIGS. 4 and 5;
FIG. 7 is a side view in cross section of an alternative embodiment; and
FIG. 8 is a plan view of one type of tension indicating strip for use in the alternative shown in FIGS. 4-7 for continuous feeding.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings in detail, FIGS. 1-3 show a reel-type loader 10 having a main body or housing portion 12 with a reel 14 rotatably mounted at one end of the body for storing a roll or strip 16 comprised of a plurality of collated tension indicating tabs as described in the above identified copending application, Ser. No. 81,819 entitled MEANS FOR INDICATING TENSION and filed Oct. 19, 1970. Such strip as best shown in FIG. 3 is a construction of plastic material having a plurality of openings 15 for receiving bolts and wires 17 and 19 embedded therein on each side of the openings and extending the entire length of the strip so as to provide an electrical circuit open at both ends. Strip 16 is wound onto the reel so that when the reel is positioned in body 12 and rotated in a clockwise direction, the strip is fed along the bottom portion 18 of body 12 through a guide 20 which prevents the strip from lifting up off bottom 18 of the body into the socket portion 22 of the adapter.
Socket portion 22 is comprised of a conventional socket 24 held within the body by a frame 26 which encloses the socket, frame 26 preferably being characterized as a spring clamp which closes around the socket but permits rotation of socket 24 in the frame. With frame 26 in the form of a spring clamp, the socket is interchangeable in adapter tool 10 so that different size joints can be tightened with the same reel adapter. Socket 24 shown in FIG. 1 has a lower portion 34 characterized by a hexigonal socket for receipt of a hex nut 36. The upper portion 28 of socket 24 has a standard square opening 30 permitting insertion of a conventional adapter tool 50 such as a hand wrench or power drill with an adapter plug 32.
The signal indicating means is provided by a battery 40 and light 42 mounted in hub portion 44 of the reel. Leads 17 and 19 projecting from the inner end of strip 16 are connected to hub 44 by a pair of set screws 43 and 45 which in turn connect the battery and light in series by a plurality of wires 47, 49 and 51. thus, an open circuit is provided which includes one wire 17 of strip 16, wire 47 connected between wire 17 of strip 16 and one terminal of battery 40; wire 49 connected between battery 40 and one terminal of the light 42; wire 51 connected between the other terminal of light 42 and the other wire 19 of strip 16. The circuit is open at the extreme free end of the strip 16. Thus, shorting across the two wires 17 and 19 of strip 16 closes the circuit energizing the light 42 and creating a signal.
It should be evident that the circuit can be closed by bridging the two wires 17 and 19 of strip 16 by means of a nut contacting the two during the fastening of said nut on a bolt or other threaded member. Thus, as described in my copending application, when a threaded joint is loaded in tension to pre-load (pre-load being the predetermined load wherein the plastic material of the tension indicating tab is partially extruded so that electrical continuity is established between the joint or hex nut 36 and the edge wires in the tab) the electrical circuit is closed and the light indicates the pre-load has been established. Such signal indicates to the operator that pre-load has been reached.
While the battery 40 and light 42 are shown mounted on an internal plate 46 in FIG. 2, it will be appreciated that various arrangements for mounting the light, battery, and wire connectors are envisioned.
OPERATION
To operate the reel-type loader 10 shown in FIGS. 1-3, a hex nut 36 is inserted in socket 24; reel 14 is manually or mechanically rotated clockwise to bring the innermost indicator tab of the strip into alignment with hex nut 36 as shown in FIGS. 1 and 3 so that the adapter tool 50 can be positioned on a fastener joint (not shown). At this point, adapter tool 50 such as an electrical drill having a plug adapter 32 for insertion into socket 24 is mounted to drive the socket. It will be appreciated that a mechanical wrench could be used in lieu of a power tool. Tool 50 is then activated to rotate socket 24 and tighten hex nut 36 onto the fastener joint. When pre-load is reached, sufficient deformation or extrusion of the tension indicating tab 16 in the work position will occur resulting in electrical continuity being established between the tab wires 17 and 19 and the joint (not shown) to close the electrical circuit operated by battery 40 thereby turning on light 42. This alerts the operator or tool that pre-load has been reached.
Once pre-load has been reached, further operation of tool 50 will increase the tensile load in the joint until the tab indicating wires 17 and 19 and material are completely sheared from between the hex nut 36 and joint bearing surface closing the electrical circuit to turn off light 42 and alert the operator or tool that minimum proof load has been reached. At this point, further operation of tool 50 should be terminated as the joint is secure. Further rotation past this point may tend to stretch the joint past its ultimate breaking point. For a more detailed description of the operation of the tension indicating tab or strip material 16, reference is made to the above identified copending application.
In lieu of manual shut off of tool 10, a circuit similar to that described in reference to FIG. 12 of the above referred to copending application could be used to automatically shut the tool off at pre-load and minimum proof load.
Once a particular joint has been secured, there is a total severance of the strip 16 so that the adapter tool 10 can be removed from the joint by lifting straight up until the hex nut 36 is clear of socket 38 at which point a new hex nut is inserted in the socket; reel 14 is rotated in a clockwise direction until the next operative tab is in position as shown in FIG. 3 and the adapter tool is then placed on the next joint to be fastened.
FIRST ALTERNATIVE EMBODIMENT
Referring now in detail to FIGS. 4-6 and 8, an injector type tool 65 is shown having a base 66 and upper portion 68. The tool is designed to supply a plurality of insertible screws or bolts 70 and a tension indicating strip 72 having a plurality of tabs 74; inject an individual screw 70 through an individual tab into the joint for tightening. In addition, the tool is designed to indicate to the operator or tool when pre-load and minimum proof load has been reached in the joint.
Referring to FIG. 4, two guide tracks 76 and 78 are aligned longitudinally in the lower or base portion 66 and spaced vertically with respect to each other. The upper guide track 76 is provided for receipt of screws 70 while the lower guide track 78 holds and guides the indicating strip 72. The base 66 is adjustably connected to the upper portion 68 by a pair of threaded bolts 79 (only one of which is shown in FIG. 4) mounted through upper portion 68 and through a pair of spaced slots 80 formed in the base so that the base is movable towards and away from the upper portion. The central portion of the base and upper portion are formed to provide an opening 81 to facilitate handling of the tool.
A plurality of screws 70 are inserted into guide track 76 through the open end 83 of the tool and a strip 72 is inserted into the lower guide track 78. Referring to FIG. 6, guide track 76 is preferably C-shaped in cross section to permit insertion of the screws 70 in the opening of the track and directionally guide them into alignment above the tabs 74. On the other hand, the lower guide track 78 is generally rectangular in cross section to act simply as an enclosed guide to directionally control strip 72 into alignment below the screws.
The electrical signal means in tool 65 (FIG. 5) includes a battery 84 and buzzer 85 mounted in the upper portion 68 and connected in series by a plurality of wires 86, 87 and 88 to a pair of fixed terminals 89 and 90, mounted in the base portion 66. Terminals 89 and 90 are rigidly mounted for cooperation with strip 72 shown more clearly in FIG. 8. The strip 72 shown in FIG. 8 includes a plurality of tension indicating tabs 74, but in addition, has a sawtooth configuration along its edges comprising a plurality of notches 122 cut laterally into the strip deep enough in penetration to expose a portion of wires 124 and 126 embedded along each edge of the strip.
The complete electrical circuitry of the signal means is thus established. With strip 72 inserted in the lower guide track 78, it is positioned as shown in FIG. 5 in alignment with screws 70. The exposed ends of the embedded wires 124 and 126 are in electrical contact with terminals 89 and 90. Terminals 89 and 90 are in turn connected to wires 87 and 88 respectively wire 88 being connected to one terminal of the battery while wire 87 is connected to one terminal of the buzzer. Wire 86 interconnects the other terminals respectively of the battery and buzzer. Prior to pre-load, with the circuit connected as described, the circuit is open and the buzzer is not activated. However, when the joint is tightened to pre-load so that electrical continuity is established between wires 124 and 126 of the strip, the circuit becomes closed and the battery actuates the buzzer. Further tightening to minimum proof load severs wires 124 and 126 to turn the buzzer off indicating to the operator of the tool that proof load has been reached. After severance, a portion of wires 124 and 126 extend out from the next tab in the strip at or near the sawtooth notch 122 which exposed ends abut against terminals 89 and 90 when the strip is advanced thereby again establishing the electrical circuit described above for the next joint.
In order to position one of screws 70 in the joint, the row of screws are advanced manually or otherwise along guide track 76 until the innermost screw (screw 70a in FIG. 4) slips off the inner end 91 of guide track 76 into passageway 93. Preferably guide track 76 has a diminishing cross-sectional C-opening at passageway 93 so that there is frictional resistance to screw 70a accidentally entering the passageway unless it is purposefully moved into it. Passageway 93 is dimensionally shaped to permit the screw to move longitudinally within the passageway but not become blocked or caught in it. The passageway passes through the entire body of the adapter tool, having one opening 95 at the top of the tool through the upper portion 68 and a lower opening 97 opening up into guide track 78 so that the tension indicating strip 72 can be positioned and aligned beneath passageway 93 so that an individual tab is aligned with the passageway. A wrench fitting 99 removably fits into passageway 93, fitting 99 having a socket 101 on one end thereof for engagement with the screw head and a plug fitting 103 on the opposite end for engagement with a power tool or hand wrench for rotation of fitting 99.
OPERATION
To operate adapter tool 65, a plurality of screws 70 are inserted in guide track 76 to load the tool. In addition, a tension indicating strip 72 is inserted in guide track 78, the strip having a plurality of tabs 74. The strip 72 is inserted until the innermost end abuts against terminals 89 and 90 which terminals contact wires 124 and 126 embedded in strip 72. This aligns opening 128 with passageway 93 so that when the screws 70 are advanced to deposited screw 70a into the passageway, the screw will pass through the tab opening 128 into the joint as shown in FIG. 4. At this point wrench fitting 99 is inserted into passageway 93 with the socket 101 fitting over the head of screw 70a. A manual or power wrench is then mounted over plug 103 and the screw is rotated. At pre-load, the plastic strip deforms to close the electric circuit by establishing continuity between wires 124 and 126 activating buzzer 85 and at minimum proof load the entire strip is severed to extinguish the buzzer therefore alerting the operator when both pre-load and proof load have been reached. Again, many electrical and mechanical variations are available to achieve various signalling, controlling and loading embodiments.
SECOND ALTERNATIVE EMBODIMENT
Referring now to FIGS. 7 and 8 in detail, FIG. 7 shows an adapter tool 100 for inserting a strip 72 identical to that shown in FIG. 8 and described in reference to the first alternative embodiment of FIGS. 4-6. Tool 100 includes a socket 106, the socket preferably being removable from the tool to permit various size sockets to be inserted in the tool. A standard square opening 108 is exposed on the upper side of the tool to permit insertion of a mechanical wrench or power tool, the socket being rotatably mounted within the adapter. A guide track 105 is provided for insertion of strip 72 so tat one of the tabs 74 can be aligned with the socket to position the tab between the nut inserted in the socket and fastener surface 110. A rotatable cam lock 112 is provided so that when strip 102 is inserted into the guide track, the cam lock is pivoted down onto the strip to lock it into position.
A signal means 114 includes a battery 116; a buzzer 118; a plurality of wires 130, 132, and 134; and a pair of clips 138 (only one of which is shown in FIG. 7). Clips 138 are mounted on the side of tool 100 so that when a tab is properly aligned below the socket, clips 138 are in electrical contact with the exposed portions of wires 124 and 126 embedded in the strip at notches 122. Wire 132 connects one of the clips to a terminal of buzzer 118; wire 130 connects the other terminal of buzzer 118 to a terminal of battery 116; and wire 134 connects the other terminal of battery 116 to the other clip 138. Thus, the identical open circuit is established as hereinbefore described with regards to the first two alternative embodiments and upon pre-load, the embedded wires 124 and 126 are shorted to activate buzzer 118; while at minimum proof load, the circuit is severed to alert the operator or tool at both pre-selected loads.
While adapter tool 100 is shown in FIG. 7 as holding a tension indicating strip 72 comprised of two indicating tabs 74, by shortening guide track 105 to the right of socket 106, the adapter can be designed for single tension indicating tab inserts where desired.
OPERATION
To operate, a nut is inserted in socket 106 and a tab is aligned beneath it for compression between the nut and fastener surface 110. With the tool positioned over the joint and a wrench or power tool inserted into the socket, the joint is tightened. At pre-load, electrical continuity is established between leads 124 and 126 and the circuit through the clips 138, battery 116 and buzzer 118 is closed. Further tightening to proof load shears the lead wires 124 and 126 opening the circuit shutting off the buzzer to indicate proof load. Again, it will be appreciated that various circuitry can be used in combination with the power tool to automatically turn the tool off at pre-load and/or proof load.
Thus, various modified adapter tools are envisioned for automatically or manually advancing a continuous tension indicating strip to reduce installation time and costs, while at the same time providing a consistent quality controlled joint.
It will be obvious to those having ordinary skill in this art that the details of construction of the particular preferred embodiments may be modified in a great many ways without departing from the unique concepts presented. It is therefore intended that the invention is limited only by the scope of the appended claims rather than by particular details of construction shown, except as specifically stated in the claims.