Adjustable tool handle

An adjustable handle and method of adjusting the cross-sectional shape of a handle is disclosed. The handle comprises a central core having a plurality of axially extending grooves each having at least two radially extending ramps as well as a sleeve having a plurality of flexible expandable members with a plurality of fins in sliding relationship with the axially extending grooves and ramps. When a user turns a knob of the handle, the sleeve is directed to slide axially within the groove such that the fins of the flexible expandable members contact the ramps thereby altering the cross sectional shape of the handle over an axial distance.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

Not applicable.

BACKGROUND

The present invention relates generally to a hand tool device. In particular, the invention relates to an adjustable handle for a hand tool device.

Small hand tools such as trowels, screwdrivers, hammers, and other hand-held tools frequently are used when performing various types of construction and home-improvement projects. The handles of these tools typically are fabricated of relatively rigid wood or plastic and have a fixed diameter and cross-sectional shape. In order to produce these and other hand tools in large quantities, a standard-size handle is typically produced and affixed to the tool element. The cross-sectional shape and dimensions of the standard size handle is determined based upon an average hand size for a user as determined by the tool manufacturer. However, these tool handles do not take into account the various grip size and strength of the users. In addition, when the tools are used for extended periods of time, the tool's rigid, fixed-diameter handle can cause user fatigue and discomfort.

SUMMARY

In order to overcome the above-stated problems and limitations, and others, there is provided a handle for a hand tool or other hand-held device that is adjustable to better conform to a user's grip, hand size, and physical condition. The cross-section of the handle can readily be adjusted by the user.

In general, the adjustable handle of the present invention comprises a central core with an outer surface having a plurality of axially extending grooves, with each of the grooves comprising a plurality of radially extending ramps that extend outward to the outer surface. The first end of the central core has an opening for receiving a tool element and the outer surface on the core proximate its second end has a threaded region. The handle also comprises a knob that is engaged with the threaded region of the central core. Positioned about the central core is a sleeve having a first end and a plurality of slots extending axially to thereby form a plurality of flexible expander members, each of the expander members having a plurality of fins that are positioned in a sliding relationship with the axially extending grooves of the central core. A cover is positioned about the plurality of flexible expander members of the sleeve.

In a second embodiment of the present invention, a tool handle capable of adjusting to a user's grip is disclosed. A tool handle is adjustable in that the user can adjust a shape of the tool handle by turning the knob in a clockwise or counterclockwise direction so as to move the sleeve, and hence, plurality of flexible expander members axially such that the fins move along the radially extending ramps in a radial and axial direction. The movement of these fins in an axial and radial direction changes the cross sectional shape of the handle.

In a third embodiment of the present invention a method of adjusting the shape of a hand tool handle is disclosed. The shape of the tool handle having the components previously discussed can be adjusted by a user gripping the cover of the handle with a user's first hand. The knob is turned in a clockwise or counterclockwise direction by a user's second hand. The movement of the knob thereby causes the sleeve and plurality of flexible expander members to move axially such that the fins move along the radially extending ramps of the central core in both radial and axial directions to adjust the handle shape within the user's first hand. This process can be repeated in either direction until the user is satisfied with the shape of the handle within the user's grip.

DETAILED DESCRIPTION

Referring now to the drawings in detail, and initially toFIG. 1, a hand shovel10or trowel is shown in perspective view. The trowel10comprises a blade12and a handle14. A detailed perspective view of the handle14is shown inFIG. 2and a side elevation view of the handle14is shown inFIG. 3.

Referring now toFIGS. 4-9, the handle14comprises a generally axially extending central core16having a core first end18, a core second end20, and an outer surface22. The outer surface22of the central core16has a plurality of axially extending grooves24located therein. The number of grooves can vary between embodiments. However, it is preferred that the plurality of axially extending grooves24comprises at least three grooves. In the embodiment shown inFIGS. 4-7, six grooves are utilized.

Located in each of the axially extending grooves24is a plurality of radially extending ramps26. The ramps26extend radially outward to the outer surface22. As it can be seen fromFIG. 4, the plurality of radially extending ramps comprises two ramps in each of the axially extending grooves24. However, a larger quantity of ramps can be utilized. Other features of the central core16comprise an opening28proximate the first end18for receiving a tool element, such as a trowel blade12.

In an alternate embodiment of the present invention, the opening28in the core16can extend from the first end18to the second end20such that the core is essentially hollow. In this configuration the tool element can pass completely through the handle14and be attached to the handle14proximate the second end20.

At the opposite end of central core16, or proximate second end20, a portion of the outer surface22is threaded as depicted by identifier30and shown inFIG. 6. Although the central core16can be fabricated from a variety of materials, for the embodiment shown inFIGS. 3-7, the central core16is preferably fabricated from a plastic such as nylon 6/6, although other plastics with similar properties can be used.

Engaged with the threaded region of the central core is a knob32that can be turned by a user to adjust the handle geometry. The knob has an external surface34having a texture that improves the grip of the user. Examples of different grip configurations are shown inFIGS. 10-13. As with the central core, the knob32is also fabricated from a plastic material.

Positioned radially about the central core16is a sleeve36that has a first end38and a plurality of slots40extending axially to a sleeve second end42, thereby forming a plurality of flexible expandable members44. Located along the radial inner side of the plurality of flexible expandable members44are a plurality of fins46. The fins46of the flexible expandable members44are positioned in a sliding relationship with the axially extending grooves24of the central core16. The quantity of fins46in the plurality of flexible expandable members44corresponds to the quantity of radially extending ramps26in the plurality of axially extending grooves24. The sleeve36, as with the central core16and knob32is also fabricated from a plastic such as glass reinforced nylon 6/6. However, other plastics with similar properties can be used.

Positioned about the sleeve36and plurality of flexible expandable members44is a cover48. The cover48is fabricated from a material that allows the user to have a secure grip on the handle14as well as permitting the handle14to expand and return to a contracted state. The preferred material for such an application is a vulcanized thermoplastic or thermoplastic elastomer with balanced polypropylene and rubber compounding to produce an acceptable hardness, stretch, and recovery memory. Another feature of the handle14is an end cap50. The end cap50is coupled to the central core16by a removable fastener52, such as a screw or bolt, and serves to limit the amount of travel by the knob32, thereby preventing it from separating from the central core16.

As previously discussed, the plurality of flexible expandable members44have fins46that are in slidable relationship with the axially extending grooves24of the central core16. Furthermore, the knob32is in threaded engagement with the second end20of the central core16. The axial position of the sleeve36and plurality of flexible expandable members44can be changed by turning the knob32and thereby moving it along the threaded portion of the second end20of the central core16. This in turn causes the sleeve36to move in axially, and due to the ramps26, in a radial direction. The knob32can be turned both clockwise and counterclockwise.

Adjusting the shape of the handle can be better understood with respect toFIG. 4andFIG. 7. In order to adjust the handle shape, a user grips the cover48of the handle14with a user's first hand. Then, a user takes their second hand and turns the knob32either in a clockwise direction or a counterclockwise direction. As such, no external tooling is required to turn the knob. Referring initially toFIG. 4, it can be seen that the plurality of flexible expandable members44are initially in an axial position in which the fins46are located adjacent the plurality of ramps26. If the user turns the knob32in a clockwise direction, the sleeve36and plurality of flexible expandable members44are moved axially away from the knob32, thereby causing the fins46to contact the radially extending ramps26move radially outward along the radially extending ramps26so as to increase the size of the handle14. This expanded handle geometry is shown in cross section inFIG. 7.

The exact change in shape and size of the handle14depends on a variety of factors including the quantity, angle, and axially spacing of the ramps26and the quantity and spacing of the axially extending grooves24. For example, if the axially extending grooves24in which the fins46are positioned are substantially equally spaced about the handle14, then the cross sectional shape of the handle14will change more uniformly than if the axially extending grooves24are unequally spaced. Therefore, for a generally round handle cross section, as shown inFIG. 5, the diameter will change more uniformly for generally equally spaced grooves24. However, the present invention is not limited to a round handle cross section, nor to generally uniform change in cross section. In fact, the cross section of the handle14can be oblong, oval, or a variety of non-uniform shapes. Another factor affecting the change in handle geometry is the quantity of ramps26, their axial spacing, and their respective angle. These factors determine the direction of cross-sectional geometry change and the axial length over which the change in handle geometry occurs. The ramps26in the embodiment disclosed herein are shown at 30 degrees relative to the horizontal. However, the ramp angles can be uniform or different so as to create a different cross sectional shape. For example, if the ramp angles alternate between 30 degrees and 45 degrees, a handle cross section can be changed from a circular shape to a square-like shape when it is expanded. The embodiment shown inFIGS. 4 and 7comprise two sets of ramps spaced apart by an axial distance. However, the present invention is not limited to this embodiment in terms of ramp quantity or spacing and could include additional ramps26that are axially spaced either the same or differently.

In the event the user wants to contract the handle size, the user turns the knob32in a counterclockwise direction allowing the cover48to contract and causing the sleeve36and plurality of flexible expandable members44to move axially towards the knob32, thereby causing the fins46to move radially inward along the radially extending ramps26so as to decrease the size of the handle14. Through this movement, the handle changes geometry from that shown inFIG. 7to that shown inFIG. 4. The process of turning the knob clockwise or counterclockwise can be repeated as required in order to adjust to handle to the user's satisfaction and comfort or to be adjusted to a different user of the tool.

An additional benefit of an adjustable handle that can be realized from this invention is the ability to adjust the handle size and shape for a user having a weakened hand condition or who has less hand strength then a typical user. By adjusting the handle geometry, the handle can better conform to the user's grip, even in a weakened state.

Although the handle configuration disclosed herein is depicted with respect to a hand tool, the adjustable handle can be utilized on other hand-held equipment and is not limited to hand tools. Other art fields that can utilize the present invention include, but are not limited to, sports equipment, cleaning equipment, and other devices that are grasped in a user's hand. Specific examples include golf clubs, tennis rackets, brooms, and mops, to name a few.