Band Tensioning Tool Insert

Abstract

A band tensioning tool is provided that employs a replaceable insert juxtaposed to a tensioning wheel. The insert is made of low-friction material wherein band galling and tension wheel slippage is drastically reduced. The tool employing the contemplated insert can tension bands of various material properties with predictable repeatability.

Description

This application claims the benefit of U.S. Provisional Application Ser. No. 61/682,014, filed Aug. 10, 2012, the entire disclosure of which is incorporated by reference herein.

FIELD OF THE INVENTION

Embodiments of the present invention are generally related to band tensioning tools. More particularly, one embodiment is a tool with an insert positioned beneath, and spaced from, a tension wheel that facilitates band tensioning and reduces tool malfunctions.

BACKGROUND OF THE INVENTION

Corrosion-resistant metallic bands are used in oil drilling operations where exposure to seawater, chemicals, drilling fluids, etc. is common. Carbon steel bands have been used in these applications and have been successfully tensioned by existing tensioning tools, such as Fromm's A480 tool. Zeron, a stainless steel with excellent corrosion resistance and high strength characteristics, is also commonly used. Nickel alloys are also used, such as Inconel and Monel, which are corrosion and heat resistant. The problem of using stainless steel or nickel alloy bands is the existing band tools provide inadequate tension and the tension provided varies from band-to-band.

FIGS. 1-4 show the Fromm A480 tool 2. The tool employs a pneumatically-driven knurled tension wheel 6 that is spaced from a replaceable insert 10 located in a breaker foot 14. A spring biases the tension wheel 6 towards the breaker foot 14. A lever 18 is used to separate the tension wheel 6 from the breaker foot 14, which allows a band to be inserted therebetween. The operator releases the lever 18 and pneumatic pressure is used to rotate the tension wheel 6 which tensions the band. That is, as the tension wheel 6 rotates, the band is pulled across the insert 10, thereby tensioning the band about an object(s). A user-controlled “pressure setting” of the tool 2 is proportional to the amount of pressure applied by the tension wheel 6 onto the band, the level of band cutting force available, and band pull speed.

When a desired band tension is achieved, the tension wheel 6 will stall or repeatedly slip at the point of band contact because the pneumatic pressure used to rotate the tension wheel 6 will be insufficient to overcome the tension exerted by the band (i.e., a force in a direction opposite from the band pull direction). When the tension wheel 6 stalls, the operator surmises that the proper band tension has been achieved and uses lock forming jaws of the tool 2 to deform a buckle or seal about the band. After the band has been locked, the excess portion of the band is severed therefrom by a pneumatically driven knife/blade mechanism of the tool. If the tension wheel 6 slips before the desired band tension is achieved, because of increased friction between the band and insert, or because the tension wheel is rendered ineffective, the operator will mistakenly believe the desired tension has been reached and will lock and cut the band prematurely.

Again, existing tools tension carbon steel bands effectively, but bands made out of stainless steel, for example, often pose problems. For instance, compression of stainless steel bands against existing inserts cause the band and/or insert to gall as the band moves relative to the insert. Galling can occur after a small number of bands are tensioned. Galling, i.e., adhesive wear of the tension wheel or the insert, adversely affects tool performance because it can cause material to be removed from the band which can clog spaces in the knurled surface of the tension wheel. As one of skill will appreciate, altering the tension wheel in this fashion causes slippage and, thus, ineffective tensioning. Tension wheel slipping also causes the tension wheel to wear prematurely. Further, galling often alters the shape of the band, which may render adding additional band seals to a severed end of a band coil difficult.

Galling is addressed in some ways by coating the band with wax, which adds cost and complexity to band manufacturing. Alternatively, tool operators choose to accept some level of galling and compensate for slipping by modifying the pressure setting to increase the pressure the tension wheel applies on the band. Regardless of the techniques used to address the slippage, studies have shown that a given number of stainless steel bands tensioned with an existing tool often deviate in band tension performance, which indicates inconsistent and unpredictable tool performance.

Another way to address galling is to employ a pinch wheel opposite the tension wheel, which is disclosed in U.S. Pat. No. 6,073,664, the entirety of which is incorporated herein. Changing existing tools to incorporate a pinch wheel would require major modifications.

Thus is a long felt need to provide a band clamping tool that provides accurate and repeatable tension from band to band. It is also desirable to provide a band tensioning tool that prevents or reduces the amount of slippage between the pinch wheel and the band and, thus, prolongs life of the tension wheel.

SUMMARY OF THE INVENTION

It is one aspect of embodiments of the present invention to provide a tool that addresses galling and performance issues commonly experienced by existing band tensioning tools. More specifically, one embodiment of the present invention employs a low-friction insert that works in conjunction with a tensioning wheel. The contemplated insert has a room temperature tensile strength between about 20,000 to 32,000 psi, room temperature tensile modulus of between about 3-4 Mpsi, room temperature flexural strength of between about 30,000 to 50,000 psi, room temperature flexural modulus of between about 4.9 to 4.12 Mpsi, room temperature compressive strength of between about 40,000-75,000 psi, and room temperature coefficient of friction of between about 0.15 to 0.20. In one embodiment of the present invention, Wearcomp® manufactured by Hycomp® was used, but one of skill in the art will appreciate that any material that meets these or similar material properties may be used without departing from the scope of the invention. Wearcomp® is comprised primarily of pmr-15 polyamide resin (40%-60%) and carbon fiber or graphite (40%-60%).

The contemplated low-friction insert is placed within a foot of the tool and is spaced from the tension wheel. In operation, a band is compressed between the tension wheel and the insert. When the tension wheel is rotated and the band tensioned, the low-friction insert allows the band to slide without galling, which increases tension wheel effectivity. As a result, the insert allows for increased tension wheel pressure to be applied, which influences band tension and pull speed.

It is one aspect of embodiments of the present invention to provide a band tensioning tool comprising: a pneumatically-powered tension wheel; a foot spaced from the tension wheel, the foot having a recess; a lever associated with the foot that selectively moves the foot away from the tension wheel; and an insert positioned in the insert, the recess being made of a low-friction material.

It is yet another aspect of embodiments of the present invention to provide a band tensioning tool comprising a gear housing having a tension wheel protruding from a portion thereof; a foot pivotally coupled to the gear housing and having a band support portion disposed generally opposite the tension wheel; a compression foot spring having a first end portion associated with the gear housing and a second end portion associated with the foot, the compression foot spring adapted to pivotally bias the band support portion of the foot toward the tension wheel; a handle having a first end portion coupled to the foot, the handle having an intermediate portion and a second end portion extending from the foot generally along the axial dimension of the gear housing, the handle being actuatable toward and away from the gear housing to pivot the foot against the pivotal bias of the compression foot spring, which moves the band support portion away from the tension wheel to provide a band-receiving gap, the improvement comprising: a low-friction insert incorporated in the foot, the low-friction insert being generally aligned with, but spaced from, the tension wheel when the handle is actuated toward the gear housing.

It is still yet another aspect of embodiments of the present invention to provide a method of securing a band about a plurality of objects, comprising: providing a band tensioning tool comprising a pneumatically-powered tension wheel, a foot spaced from the tension wheel, the foot having a recess, a lever associated with the foot that selectively moves the foot away from the tension wheel, and an insert positioned in the insert, the recess being made of a low-friction material; moving the lever to separate the foot from the tension wheel; placing a band between the tension wheel and the foot; releasing the lever which moves the insert into engagement with the band, the band also being engaged to the tension wheel; rotating the tension wheel, which moves the band across the insert; achieving a predetermined band tension; deforming a seal about the band to create a band loop; and severing an excess portion of the band.

The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. The present invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present invention will become more readily apparent from the Detail Description, particularly when taken together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.

FIG. 1 is a perspective view showing a band tensioning tool of the prior art;

FIG. 2 is a front elevation view of FIG. 1;

FIG. 3 is a detailed view of FIG. 1 showing the bottom portion of the tool;

FIG. 4 is a detailed view of FIG. 1 showing a tension wheel spaced from an insert;

FIG. 5A is a perspective view of an insert employed by one embodiment of the present invention;

FIG. 5B is a front elevation view of FIG. 5A;

FIG. 5C is a side elevation view of FIG. 5A;

FIG. 6 is a table showing retained force of bands of various material compositions tensioned with a tool of one embodiment of the present invention;

FIG. 7 is a table showing loop tensile force achieved by bands tensioned with tools of one embodiment of the present invention;

FIG. 8 is a table showing band pull speed provided by one embodiment of the present invention;

FIG. 9 is a table comparing steel inserts with inserts employed by some embodiments of the present invention;

FIG. 10A is a perspective view of a tool showing removal of side cover screws;

FIG. 10B is a perspective view of a tool showing removal of the tool side cover;

FIG. 10C is a perspective view of a tool showing removal of a tension wheel;

FIG. 10D is a perspective view of a tool showing removal of an existing insert or the replacement of a low-friction insert; and

FIG. 10E shows the installation of the replacement insert into a foot.

It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

As briefly described above, FIGS. 1-4 show a band tensioning tool 2 commonly used in the industry to tension a band claim. The tool 2 includes pneumatically-driven tension wheel 6 that is spaced from a foot 14 that accommodates a low-friction insert 10. In operation, the user moves a lever 18 that moves the foot 14 away from the tension wheel 6, which allows a band to be placed therebetween. When the lever is released, the band is compressed between the low-friction insert 10 and the tension wheel 6. A pneumatic motor is initiated to rotate the tension wheel to tension the band. After a predetermined tension is achieved, a locking mechanism is employed that deforms a portion of a seal about the band, which maintains the applied tension, and the excess band portion, which extends beyond the seal, is severed. The components and functionality of existing tools is described in U.S. Pat. No. 4,380,255, which is incorporated by reference herein, and the previously-mentioned U.S. Pat. No. 6,073,644. The contemplated low-friction insert may be incorporated into these, or similar, tools. The Locking a seal by crimping is described in U.S. Pat. No. 7,484,274, which is incorporated by reference herein.

FIGS. 5A-5C shows a low-friction insert of one embodiment of the present invention. Although the shape of this insert is circular, one of skill in the art will appreciate that the insert may have any shape so long it can be accommodated in a cavity provided in the foot. The insert may also include a cavity that receives a secondary insert that is removable therefrom.

FIG. 6 is a table showing retained force of bands that were tensioned using a stock Fromm tool versus those using a Fromm tool employing the contemplated low-friction insert. Here, bands made of Zeron, Alloy 400, 304 stainless steel (one quarter hard), and 316 stainless steel were tensioned. A retained force (i.e., the force exerted on the objects by the band) of about 500 pounds was achieved when a Zeron band was tensioned with a stock Fromm tool and a retained force of about 280 pounds achieved by a tool using a tool with a low-friction insert. When tensioning an alloy 400 band, the stock tool produced a retained force of about 150 pounds compared to a retained force of about 250 pounds achieved by a tool with a low friction insert. In the case of a 304 stainless steel (one-quarter hard) band, the retained force was 550 pounds using the stock tool and about 340 pounds when using a tool with a low friction insert. Finally, when a 316 stainless steel band was tensioned using a stock tool, 90 pounds of retained force was attained compared to about 210 pounds using the low friction insert. Accordingly, one of skill in the art will appreciate that a tool employing a low-friction insert provides a more predictable and consistent band clamp performance over a wide range of materials compared to the stock tool.

These test results illustrate band performance repeatability, which is important, as users will often use bands of different materials for different applications. In the past, the band material would dictate the amount tension applied wherein the user would have to modify tool parameters to achieve the desired tension. Embodiments of the present invention address this issue by providing an insert that tensions bands of different materials to the same level degree, thereby increasing repeatability and reliability. For example, bands made of Zeron, Alloy 400, 304 stainless steel, and 316 stainless achieve a retained force of at least about 200 psi. The table shows that the retained force of bands applied by the stock Fromm tool varies depending on band material. Repeatability is often the driving force in banding operations, because it allows users to be confident that the tension applied to each band meets a predefined design criteria.

FIG. 7 shows that a tool employing a low-friction insert clamp strength will be unchanged over a wide range of pressure settings. More specifically, the loop tensile force provided by a band tensioned with a tool employing a low friction insert is about 3,500 lbf regardless of the tool pressure, i.e., pressure the tension wheel imparts on the band and insert, which is comparable to the tool loop tensile force provided by band tensioned with the stock tool. Thus using a low-friction insert does not adversely affect loop tensile performance.

FIG. 8 shows bands may be tension much faster when using a low friction insert. More specifically, tools using a low-friction insert are capable of operating at lower torque because excess power is not needed to counteract friction associated with the band moving across the insert. Such tools are desirable as they can pull band at higher speeds while applying the desired tension and while providing sufficient pneumatic pressure to sever bands of various materials. Employing a low-friction insert, the pull speed may be doubled because a high speed motor may be used. Conversely, prior art tools cannot use a high speed motor because of the detrimental effects of tension wheel slipping and/or galling, which affects the applied tension and which can stall the tool. Here, a tool employing a low-friction insert has a band speed rate of about 7 in./s wherein the prior art insert allows for a band pull speed of about 3.2 in./s (because a low-speed transmission is commonly used). As one of skill in the art will appreciate, pull speed is directly related to the amount of bands that can be installed in a given amount of time.

Referring now to FIG. 9, Zeron and Alloy 400 (full hard) bands were tensioned using a stock Fromm A480 tool and a Fromm A480 tool employing a low-friction insert. The stock tool produced bands tensioned to about 508 lbf (Alloy 400) and 629 lbf (Zeron). The tool employing a low friction insert performed much better, tensioning bands to about 1196 lbf (Alloy 400) and about 1301 lbf (Zeron). The standard deviation of band tension was also reduced when using a modified tool by an order of magnitude, from 284 to 34 for Zeron and from 145 to 58 for Alloy 400. Use of a low-friction insert increased tension on average about 673 lbf (Zeron) and 688 lbf (Alloy 400) over existing inserts. Further, the repeatability in performance is desirable to operators as they can tension many bands without having to make adjustments to the tool configuration.

Further, embodiments of the present invention reduce galling in stainless steel bands. In one test, 10,000 pulls were performed without failure, i.e., tension wheel slippage. Also, the nature of the contemplated low-friction insert allows it to be reversible (i.e., removed, flipped over, and replaced), thereby doubling its life and lowers tension output, which reduces the risk of damage to the seal and band at higher pressure settings.

With reference now to FIGS. 10A-10E, modification of a stock tool is shown. Initially, side cover screws 18 are removed and the side cover 22 is pried from the tool, which exposes the tension wheel 6 and insert screw 26. The tension wheel 6 and insert 10 are then removed. The replacement insert 10 is then installed into the foot 14 of the tool and a tension wheel 6 is placed back on its axle 30. Minute changes can be made to the gap between the tension wheel 6 and the insert 10. Finally, the side cover 22 and screws 18 are placed back on the tool and gap adjustment screws are used to further maintain a predetermined gap between the tension wheel 6 and the insert 10.

Although described numerous times herein, the aspects of the present invention are not limited to the Fromm A480 tool. That is, one of skill in the art will appreciate that tools of other manufacture and type can be used without departing from the scope of the invention.

While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

1. A band tensioning tool comprising:

a pneumatically-powered tension wheel;

a foot spaced from said tension wheel, said foot having a recess;

a lever associated with said foot that selectively moves said foot away from said tension wheel; and

an insert positioned in said insert, said recess being made of a low-friction material.

2. The tool of claim 1, wherein said low-friction insert has a room temperature tensile strength of between about 20,000 to 32,000 psi, room temperature tensile modulus of between about 3-4 Mpsi, room temperature flexural strength of between about 30,000 to 50,000 psi, room temperature flexural modulus of between about 4.9 to 4.12 Mpsi, room temperature compressive strength of between about 40,000-75,000 psi, and room temperature coefficient of friction of between about 0.15 to 0.20.

3. The tool of claim 1, wherein said low friction insert has a coefficient of friction of between about 0.15 to 0.20.

4. The tool of claim 1, wherein said low friction insert has a coefficient of friction of between about 0.05 to 0.40.

5. The tool of claim 1, wherein said low friction insert is made of a composition comprised of a mixture of between about 40%-60% pmr-15 polyamide resin and between about 40%-60% of at least one of carbon fiber and graphite.

6. The tool of claim 1, wherein said insert has a circular outer perimeter.

7. A band tensioning tool comprising a gear housing having a tension wheel protruding from a portion thereof; a foot pivotally coupled to said gear housing and having a band support portion disposed generally opposite said tension wheel; a compression foot spring having a first end portion associated with said gear housing and a second end portion associated with said foot, said compression foot spring adapted to pivotally bias said band support portion of said foot toward the tension wheel; a handle having a first end portion coupled to said foot, said handle having an intermediate portion and a second end portion extending from said foot generally along the axial dimension of said gear housing, said handle being actuatable toward and away from said gear housing to pivot said foot against the pivotal bias of said compression foot spring, which moves said band support portion away from said tension wheel to provide a band-receiving gap, the improvement comprising:

a low-friction insert incorporated in said foot, said low-friction insert being generally aligned with, but spaced from, said tension wheel when said handle is actuated toward said gear housing.

8. The tool of claim 7, wherein said low-friction insert has a room temperature tensile strength of between about 20,000 to 32,000 psi, room temperature tensile modulus of between about 3-4 Mpsi, room temperature flexural strength of between about 30,000 to 50,000 psi, room temperature flexural modulus of between about 4.9 to 4.12 Mpsi, room temperature compressive strength of between about 40,000-75,000 psi, and room temperature coefficient of friction of between about 0.15 to 0.20.

9. The tool of claim 7, wherein said low friction insert has a coefficient of friction of between about 0.05 to 0.40.

10. The tool of claim 7, wherein said low friction insert is made of a composition comprised of a mixture of between about 40%-60% pmr-15 polyamide resin and between about 40%-60% of at least one of carbon fiber and graphite.

11. A method of securing a band about a plurality of objects, comprising:

providing a band tensioning tool comprising a pneumatically-powered tension wheel, a foot spaced from said tension wheel, said foot having a recess, a lever associated with said foot that selectively moves said foot away from said tension wheel, and an insert positioned in said insert, said recess being made of a low-friction material;

moving said lever to separate said foot from said tension wheel;

placing a band between said tension wheel and said foot;

releasing said lever which moves said insert into engagement with said band, said band also being engaged to said tension wheel;

rotating said tension wheel, which moves said band across said insert;

achieving a predetermined band tension;

deforming a seal about said band to create a band loop; and

severing an excess portion of said band.

12. The method of claim 11, wherein said band does not substantially gall when it moves across said insert.

13. The method of claim 11, wherein said tool is capable of tensioning bands made of at least one of a carbon steel, a stainless steel alloy, and a steel/nickel alloy, wherein retained force is between about 200-400 lbf. is achieved, regardless of band material.

14. The method of claim 11, wherein said tool is capable of tensioning bands made of at least one of Zeron, Alloy 400, one-quarter hard 304 stainless steel, and 316 stainless steel, wherein retained force is between about 200-400 lbf. is achieved, regardless of band material.

15. The method of claim 11, wherein said tool is capable of tensioning a plurality of Zeron bands with a standard deviation associated with applied band tension is about 30-40.

16. The method of claim 11, wherein said tool is capable of tensioning a plurality of Zeron bands such that a standard deviation associated with applied band tension is reduced by about 80-90% with respect to a similar tool that does not employ a low-friction insert.

17. The method of claim 11, wherein said tool is capable of tensioning a plurality of Alloy 400 bands with a standard deviation associated with applied band tension is about 50-60.

18. The method of claim 11, wherein said tool is capable of tensioning a plurality of Alloy 400 bands such that a standard deviation associated with applied band tension is reduced by about 55-65% with respect to a similar tool that does not employ a low-friction insert.

19. A band tensioned by the method of claim 11.