Tool accommodating replaceable blade

A cutting tool utilizing a replaceable blade has a body which defines a blade-accepting pocket having an interior within which the body of the blade is nestingly accepted when inserted within the pocket and for releasable securement of the blade within the blade-accepting pocket. Furthermore, the blade-accepting pocket includes an abutment surface against which a surface of the blade body bears against when the cutting edge of the blade is moved into cutting engagement with an item being cut with the tool.

BACKGROUND OF THE INVENTION

This invention relates generally to tools having wearable cutting edges and relates, more particularly, to tools which utilize replaceable blades.

Tools to which this invention is to be compared include common hand tools having cutting edges which are susceptible to wear. If such a cutting edge is embodied within the body of the tool, the entire tool might have to be replaced when the cutting edge becomes worn or damaged. Of course, to replace the entirety of a tool in order to replace a worn or damaged cutting edge may be undesirable because of the costs involved or because of the need to break in a new tool. Examples of hand tools which commonly include cutting edges include wire cutters, wire strippers and pliers whose jaws embody a pair of opposing cutting edges which are urged into engagement with an item to be cut as the item to be cut is squeezed between the jaws.

Tools are known which utilize edge-defining blades which are intended to be replaced when worn or damaged or, in the alternative, are intended to be rotated to expose an unused cutting edge of a blade. However, the blades of such tools commonly require the use thereof of a shaft or other locking member which extends through a pre-formed hole provided in the body of the blades in order to secure the blades within the tool. An example of one such tool which utilizes replaceable blades is shown and described in U.S. Pub. No. 2006/0150418.

Among disadvantages associated with such a tool (i.e. one that utilizes a pre-formed hole through which a shaft is accepted) is that if the blade and shaft are comprised of metal and the blade comes into contact (e.g. during a cutting operation) with a live electrical wire, an arc fault, or grounding, of the wire through the blade could rapidly heat the blade and shaft to thereby effectively weld the blade and shaft together. If such a welding event occurs, the blade will be difficult, if not impossible, to remove from the tool.

It would be desirable to provide a new tool which accommodates the replacement of a worn or damaged blade without requiring that the body of the blade be provided with a pre-formed hole for securement of the blade within the tool or that the blade be secured within the tool with a shaft or other locking member which extends through a pre-formed hole provided in the blade.

Accordingly, it is an object of the present invention to provide a new and improved tool which accommodates the acceptance of a replacement blade therein.

Another object of the present invention is to provide such a tool having a blade-acceptance system which enables a worn or damaged blade to be replaced relatively quickly.

Still another object of the present invention is to provide such a tool which adequately supports a replaceable blade for use.

Yet another object of the present invention is to provide such a tool whose blade-acceptance principles are well-suited for incorporation in both hand tools and machine tools.

A further object of the present invention is to provide such a tool whose blade-acceptance system is uncomplicated in structure, yet effective in operation.

SUMMARY OF THE INVENTION

This invention resides in an improvement to a tool having a body for accepting a replaceable blade.

The improvement is characterized in that the body of the tool defines a blade-accepting pocket for nestingly accepting the replaceable blade inserted therein for releasable securement of the blade within the blade-accepting pocket.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

Turning now to the drawings in greater detail and considering firstFIG. 1, there is illustrated an embodiment, generally indicated20, of a tool within which features of the present invention are embodied. Briefly, the tool20is in the form of a pair of wire cutters having a body52including a pair of jaw portions (or jaws22,24)which are moveable toward and away from one another and a pair of handle portions (or handles26,28)which are associated with the jaws22,24for movement of the jaws22,24toward or away from one another. In the depicted tool20, the handles26,28are elongated in shape and are joined together at one end thereof to permit a pivotal movement of the jaws22,24about a pivot axis29toward or away from one another as the handles26,28are manipulated by a user.

More specifically, each jaw22or24of the tool20is incorporated within a corresponding handle26or28of the tool20, and a spring (not shown) is mounted internal of the tool20for acting between the handles26and28in a manner which biases the ends of the handles26,28opposite the joined ends thereof further apart. Therefore, the jaws22and24are moved toward one another as the user squeezes the handles26and28of the tool20toward one another in opposition to the biasing force of the internal spring of the tool20. By comparison, the jaws22and24are permitted to move apart under the biasing influence of the internal spring as the user loosens his grip upon the handles22,24.

For purposes of cutting wire with the tool20, the tool20utilizes a pair of cutting blades30which are positionable within the jaws22,24of the tool20. As best shown inFIGS. 2-5, each blade30includes a body32which is elongated in shape having a leading (substantially linear) cutting edge34, two opposite end walls36,38which extend rearwardly of the cutting edge34at substantially a right angle with respect thereto, a pair of side faces40,42which extend between the end walls36,38, and a trailing, or rear, edge44which also extends between the end walls36,38and along the blade body32opposite the cutting edge34. Within the depicted blade30, the cutting edge34is relatively sharp as a path is traced therealong, while each of the side faces40,42and trailing edge44is substantially planar. Furthermore, each of the end walls36or38is rounded in shape, and one of the side faces40of the blade body32defines a shallow detent46in the form of a substantially semi-spherical indentation for a reason which will be apparent herein.

It is a feature of the present invention that the tool20includes means, generally indicated48, defining a blade-accepting pocket50within which the blade30can be inserted for use. Although the pocket50can take any of a number of forms, the pocket50of the depicted tool20includes a substantially linear access passageway51which is collectively defined by two opposing and arcuate-shaped end walls54,56, a substantially planar side wall58which extends between the end walls54,56and a substantially planar bottom60which extends between the end walls54,56. As best shown inFIG. 7, the curvature of the end walls54,56provide the surfaces of the end walls54,56with somewhat of a C-shaped cross section wherein the Cs of the C-shaped walls54,56open toward one another. At the entrance of the access passageway51is provided an access opening62which opens generally upwardly and away from the bottom60of the pocket50(as seen inFIGS. 2 and 6).

As will be apparent herein, the two C-shaped end walls54,56are substantially parallel to one another and provide guide tracks along which the rounded end walls36and38of a blade30are permitted to slide during a blade insertion process. In other words and to insert a blade30into the pocket50, the body32of the blade30is inserted trailing edge44-first through the access opening62and along the passageway51so that the end walls36,38of the blade body32slide downwardly along the guide tracks formed by the surfaces of the C-shaped end walls54,56of the pocket50. The blade30is fully inserted within the pocket50when its trailing edge44strikes, or comes to rest upon, the bottom60of the pocket50. With the end walls36,38of the blade30positioned within the pocket50in this manner, the rounded end walls36,38of the blade30are captured by, or confined between, the Cs of the C-shaped surfaces of the end walls54,56of the pocket50.

It follows from the foregoing that when fully inserted within the pocket50, the blade30is nestingly accepted therein. For purposes of the present invention, the phrase “nestingly accepted” is intended to mean the acceptance of the blade body32by the pocket50so that the blade body32is captured within the pocket50(e.g. with the perimeter walls of the blade body32in engagement with the walls of the pocket50) in a manner which prevents the blade40from moving relative to the pocket50along each of two coordinate axes (e.g. X and Y coordinate axes) by any appreciable amount. To this end, the cross-sectional shape of the access opening62can be substantially complimentary to that of the transverse cross-sectional shape of the blade body32so that when fully inserted within the pocket50, the blade body32is closely accepted by the walls of the pocket50which collectively provide the access opening62thereof.

In the depicted tool20, the pocket50is adapted to accept the body32of the blade30as the blade30is inserted trailing edge44-first into the access opening62of the pocket50. Thus, the perimeter walls of the blade body32which are nestingly accepted by the pocket50include the end walls36,38and the side faces40,42of the blade body32. In other words, once the blade body32is positioned within the pocket50so that the trailing edge44of the blade body32rests upon, or abuts, the bottom60of the pocket50, none of the end walls36,38or the side faces40,42are permitted to shift in directions normal to the surfaces of these end walls36,38or faces40,42by any measurable amount.

The blade30can be releasably secured within the pocket50(and thus prevented from inadvertently falling out of the pocket50by way of the access opening62) by any of a number of means or methods, but within the depicted tool20, the blade30is prevented from falling out of the pocket50by way of a spring-biased ball assembly66which is mounted within the body52of the tool20for cooperating with the blade30when the blade30is fully inserted within the pocket50. In particular and as viewed inFIG. 7, a bore70is formed within the tool body52so as to extend part-way therethrough and so that the bore70opens into the pocket50from one side thereof. More specifically, the bore70opens into the pocket50at a location which is close to or coincident with the geographical mid-point of the pocket sidewall58.

Also included within the ball assembly66is a small steel ball72which is positioned within the bore70to accommodate movement therealong and a compression spring74which acts between the bottom (or terminal end) of the bore70and the ball72to urge the ball72away from the bottom of the bore70. When assembling the tool20, the compression spring74is inserted endwise into the bore70and then the ball72is urged into the bore70against the biasing force of the spring74, and then the sidewall58of the pocket50is slightly deformed (such as in a swaging process) to permit only a portion of the ball72to protrude from the opening of the bore70. With the ball assembly66secured within the bore66in this manner, the compression spring74continually urges the ball to a position at which a portion of the ball72protrudes from the bore opening.

Before the blade body32is inserted trailing edge44—first into the pocket50, care should be taken to ensure that the blade side face40will face the pocket sidewall58as the blade30is inserted into the pocket50. Oriented in such a manner, the trailing edge44of the blade body32can then be directed downwardly into the pocket50and into engagement with the portion of the ball72which protrudes from the bore70, or more specifically, the opening, or mouth, of the bore70. At that point, the trailing edge44slides across the bore opening and urges the ball72to a retracted position within the bore70against the biasing force of the compression spring74so that the blade30is permitted to continue to slide across the bore opening while the ball72is maintained in a retracted condition within the bore70as the blade side face40slides across the ball72. When the blade body32is fully inserted within the pocket50, the detent46provided in the side face40of the blade body32is aligned with the bore opening so that the ball72(or, more specifically, a portion of the ball72), is accepted by the detent46for releasably securing the blade body32in place within the pocket50. Although the acceptance of the ball72by the detent46is sufficient to prevent the blade30from inadvertent removal from, or falling out of, the pocket50, it is not strong enough to prevent a desired removal of the blade30from the pocket50if the blade body32were to be forced upwardly from the bottom60of the pocket50.

Although the blade-accepting pocket50of only one jaw24of the tool20has been described herein for accepting a blade30, it will be understood that the other jaw22of the tool20includes an identical blade-accepting pocket50for nestingly accepting a blade30inserted within the pocket50.

Accordingly, identical components of the blade-accepting pocket50of the tool jaw22are identified withinFIGS. 1 and 2with identical reference numerals.

During a cutting operation performed with the tool20, the jaws22,24of the tool20are positioned in a spaced, or spread apart, condition to accommodate the insertion of an item to be cut, such a piece of wire, between the opposing cutting edges34of the blades30. Once the item to be cut is positioned between the blades30, the jaws22,24are moved toward one another to bring the cutting edges34of the blades30into contact with the item. The application of sufficient (squeezing) pressure upon the jaws22,24effects the cutting of the item in two pieces in what is believed to be a combination of severing and pinching actions of the cutting edges as the item is squeezed between the opposing cutting edges34of the blades30. It therefore follows that during a cutting operation performed with the tool20, forces which are applied to the item being cut by the blade are directed toward and into the item. Accordingly, the reaction forces which act upon each blade30by the item being cut urge each blade30toward the bottom60of its corresponding pocket50. Thus, the relationship between the bottom60of the pocket50and the direction that cutting forces are applied to an item to be cut contributes to the securement of the blade30within its corresponding pocket50and is advantageous in this respect.

Although each blade30of the tool20has been shown and described as being releasably secured within its corresponding pocket50by way of a spring-biased ball assembly66, there exists alternative schemes for releaseably securing a blade within the interior of a blade-accepting pocket in accordance with the broader principles of the present invention. For example, there is illustrated in FIG.8a tool jaw, generally indicated78, having a body80provided with an internally-threaded through-bore82which opens into the interior of the pocket50through the sidewall58thereof. As is the case with the bore70of the tool20, the through-bore82of the tool body80opens into the pocket interior at a location which substantially corresponds with the geometric mid-point of the pocket sidewall58. Threadably accepted by the through-bore82is a set screw84whose shank portion86can be tightened against the side face40of a replacement blade30after the blade30has been inserted within the pocket50.

The set screw84, whose head is accessible through the tool body80through the side thereof opposite the pocket50, is withdrawn from (i.e. backed away from) the pocket interior to accommodate the insertion of a replacement blade30into the pocket interior, and upon insertion of the blade30into the pocket50, the set screw84is appropriately rotated so that the set screw is tightened against the blade side face40. With the set screw84tightened against the blade30in this manner, the blade30cannot be dislodged from or fall out of the pocket50through the access opening62thereof. It also follows that in order to remove the blade30from the pocket interior through the access opening62will require that the set screw84be loosened from the blade side face40.

Furthermore, there is depicted inFIGS. 9aand9ban alternative scheme for releasably securing a replaceable blade90within the interior of a blade-accepting pocket92of a tool, indicated94. Within theFIG. 9tool94, the opposing end walls, indicated96,98, of the blade-accepting pocket92are tapered slightly inwardly toward one another as a path is traced downwardly along the pocket92from the access opening thereof so that upon full insertion of the blade90into the pocket92, the opposite sidewalls, indicated88,89inFIG. 9a, of the blade90become wedged between the opposing end walls96,98of the pocket92to releasably secure the blade90within the pocket92. In other words, the blade-accepting pocket92of the tool94is sized to frictionally grip the perimeter surfaces of the blade90when the blade90is nestingly accepted by the pocket92so that the blade90is prevented from easily dislodging from the pocket92because of the frictional- gripping engagement between the inner surfaces of the pocket92and the perimeter surfaces of the blade90.

It is also a feature of the present invention that there is associated with each blade-accepting pocket of a tool, like that of theFIG. 1tool20, a slot102which facilitates the removal of a blade from the interior of a pocket with another tool, such as a flat-tipped screwdriver100(FIG. 10). In this connection and as best depicted inFIG. 6, such a slot102can be U-shaped in form having a base104and two spaced-apart legs106which extend from the base104and toward the interior of the pocket50. More specifically, the U-shaped slot102opens into, and is in communication with, the interior of the pocket50and the base104of the slot102, which is preferably flat, is substantially parallel to the bottom60of the pocket50.

When it is desired to remove a blade30from the tool pocket50and which reference toFIG. 10, the tipped end110of a flat-tipped screwdriver100can be inserted endwise into the slot102to position the tipped end110between the base104of the U-shaped slot102and the trailing edge44of the blade30. The screwdriver100can thereafter be twisted (i.e. rotated) one-quarter of a turn about its longitudinal axis so that the tipped end110acts between the slot base104and the trailing edge44of the blade30to force the trailing edge44to move away from the bottom60of the pocket50. Once moved away from the bottom60of the pocket50, the blade30can either be grasped with the fingers or between the jaws of a pair of pliers to manually lift the blade30from the pocket50.

With reference toFIGS. 11-13, there is depicted an alternative tool, generally indicated114, for cutting holes in sheet metal and which incorporates the principles of the present invention and a blade116which cooperatively interfits with the tool114to accommodate a cutting operation with the blade116as the blade116is rotated about an axis117. In this connection and as best shown inFIG. 13, the tool116is in the form of a tool holder118which includes a conical end portion120and a shank portion122which is joined to the conical end portion120and which enables the holder118to be firmly held within the chuck (not shown) of a rotatable device, such as a drill. Meanwhile, the conical end portion120has a body124within which is defined a blade-accepting pocket126provided by a pair of shallow notches128wherein each notch128extends linearly along the conical end portion120from the tip, indicated130, of the conical end portion120. Each of these notches128are substantially rectangular in cross section and open tangentially of the conical end portion120. The tool114can also be provided with a groove115which extends axially along the length of the conical end portion120to promote the removal of cut material away from the workpiece being cut with the tool114.

The blade116which is intended to the used with the conical end portion120is best shown inFIG. 13and is V-shaped in form and has substantially linear leg portions132which are substantially rectangular in cross section and which are joined to one another along an apex136. Furthermore, the blade116has cutting edges134which extend along the outer periphery of the leg portions132of the V-shaped form of the blade116. To install the blade116within the tool114, the blade116is oriented so that the interior of its V-shape is positioned in registry with the conical end portion120as depicted inFIG. 13so that the linear leg portions132are aligned with the notches128defined along the outer surfaces of the conical end portion124. The blade116is then moved toward the tip130of the conical end portion120of the tool114so that the underside surfaces of the leg portions132of the blade116are slidably accepted by the notches128provided along the length of the conical end portion120. The blade116continues to be urged along the length of the notches128until the underside of the leg portions132are fully accepted along the length of the notches128. At that point, the shank portion122of the tool114can be mounted within the chuck of a rotatable device, rotated by the device along the longitudinal axis of the tool14and thereafter moved in a manner which brings the cutting edges134of the blade116into cutting engagement with an item (e.g. a piece of sheet material) to be cut.

It follows from the foregoing that tools have been described wherein each tool possesses a body for accepting a replaceable cutting blade inserted therein and wherein the cutting blade includes a body defining a cutting edge; The body of the tool defines a blade-accepting pocket for nestingly accepting the replaceable blade inserted therein for use of the cutting edge of the blade. In one such embodiment of the tool, the notch defines an abutment surface against which the blade is positioned so that as the blade is moved into cutting engagement with an object to be cut, the reaction forces exerted upon the blade by the object during a cutting operation are opposed by the abutment surface and help to hold the blade within the pocket.

Furthermore and in instances in which a cutting tool which incorporates the principles of the present invention are used to cut live electrical wire, the absence of a metal shaft which extends through the blade reduces the likelihood that the blade will become permanently lodged within the blade-accepting pocket if, for example, the blade were to be excessively heated (i.e. melted) from an arc fault, or grounding, of the wire through the blade.

It will be understood that numerous modifications and substitutions can be had to the aforedescribed embodiment without departing from the spirit of the invention. For example, although a blade-accepting pocket50has been shown and described within the tool20ofFIGS. 1 and 2as being embodied within the jaw of a tool which is disposed on the same side of the pivot axis as are the handles of the tool, a blade-accepting pocket can be disposed on the side of a pivot axis opposite the handles of the tool. For example, there is illustrated inFIG. 14an example of a needle-nose pliers140having a pair of jaws144and handles146which are joined to one another for movement about a pivot axis142disposed generally between the jaws144and the handles146. In this set of pliers140, blade-accepting pockets148for holding blades149are provided in the jaws144so as to be positioned to one side of the pivot axis142opposite the handles146.

Furthermore and although the blades of the aforedescribed tools have seen shown and described as being used for severing an item, such a wire, in two pieces, a blade can be inserted within the blade-accepting pocket which is intended for other purposes. For example, there is illustrated inFIG. 15a blade150which possesses a size comparable to that of the blade30ofFIGS. 3-5to permit the use of the blade150within the blade-accepting pocket50of theFIG. 1tool20, but instead of possessing a leading cutting edge34, the blade150can possess any of a number of multiple arcuate-shaped cutting edges, such as cutting edges152and154which define with a companion blade mounted within the opposite tool22a wire stripper capable of stripping insulation off of a wire, such as an electrical wire, which possesses an insulating (e.g. plastic) sheath along its length. It also follows that the openings152,154can possess different sizes for purposes of stripping the insulation from electrical wires of different sizes.

Accordingly, the aforedescribed embodiments are intended for the purpose of illustration and not as limitation.