WO2009132288A2

WO2009132288A2 - Inline handheld power tool

Info

Publication number: WO2009132288A2
Application number: PCT/US2009/041689
Authority: WO
Inventors: Patrick J. Whelan
Original assignee: Whelan Patrick J
Priority date: 2008-04-25
Filing date: 2009-04-24
Publication date: 2009-10-29
Also published as: WO2009132288A3; US20090088052A1

Abstract

A powerhead for a hand held power tool includes a powerhead assembly, the powerhead assembly being operably couplable to a hand held motive source, the powerhead assembly having a rotatable implement, the implement being selectively rotated by the motive source when the motive source is operably coupled to the powerhead assembly, the implement further being rotatable about an implement axis, the implement axis being disposed transverse to a powerhead assembly longitudinal axis, the implement axis intersecting the powerhead assembly longitudinal axis. A hand held power tool and a powerhead of forming a powerhead for a hand held power tool are further included.

Description

INLINE HANDHELD POWER TOOL

Field of the Disclosure

This disclosure relates to handheld power tools and, more particularly, to handheld power tools for cutting and grinding workpieces.

Background of the Disclosure

Handheld power tools are used for many applications. For instance, they can be used to cut a workpiece. Cutting a workpiece can include cutting across the surface of a generally planar workpiece, cutting off an end of a length of workpiece, and so forth. Workpieces may comprise materials such as wood, metal, plastic, glass, and so forth.

Handheld power tools can also be used to grind a workpiece. Grinding involves the removal of material from a workpiece surface by abrasion. Grinding a workpiece can produce smooth or fine surface finishes. Another application of grinding includes producing channels, slots, and grooves in a surface of a workpiece.

A prior art angle grinder is one example of a handheld power tool that is used for cutting and grinding. An angle grinder includes an abrasive rotatable implement rotatably mounted to a powerhead assembly at the end of a motive source. The housing of the motive source often serves as a handle. Typically, the abrasive rotatable implement is coupled to a gearbox and driven by an electric motor, AC or DC, or compressed air. Electric motors can be supplied with electric energy via either an external power source or a battery, such as a rechargeable battery.

In typical prior art angle grinders, such as those shown in Figs. 1-3, the abrasive rotatable implement is offset from a longitudinal axis of the motive source and/or set at an angle to a longitudinal axis of the motive source. The axis of rotation of the implement does not intersect the longitudinal axis. The offset can disadvantageous^ limit the inherent stability of an angle grinder and, as a result, its functionality. For example, the offset and/or angle of the abrasive rotatable implement makes cutting or grinding along a straight line unstable. Further, the offset and/or angle of the abrasive rotatable implement makes aligning the rotatable implement with an intended location of a cut, cutoff, or grinding area difficult. Thus, the accuracy and precision of machining a workpiece can be diminished by an abrasive rotatable implement that is offset or angled.

The following U.S. Patent and U.S. Patent Publication references provide examples of grinding tools and are expressly incorporated herein by reference for all purposes: D330496, D333766, 5384985, 6669542, 6860260, 6981907, 6386961, 7014548, and 2006/0276114.

A hand held power tool with an inline rotatable implement is needed in the industry.

Summary of the Invention The present invention substantially meets the aforementioned needs of the industry.

Embodiments of the present invention are directed to a powerhead for a hand held power tool and includes a powerhead assembly, the powerhead assembly being operably couplable to a hand held motive source, the powerhead assembly having a rotatable implement, the implement being selectively rotated by the motive source when the motive source is operably coupled to the powerhead assembly, the implement further being rotatable about an implement axis, the implement axis being disposed transverse to a powerhead assembly longitudinal axis, the implement axis intersecting the powerhead assembly longitudinal axis. The present invention is further a hand held power tool and a method of forming a powerhead for a hand held power tool. Brief Description of the Drawings

Figs. 1-3 are perspective views of prior art angle grinders;

Fig. 4 is a side-view drawing of a handheld power tool with an inline blade according to the present rotatable implement disclosure; Fig. J is a top-view drawing of another embodiment of a handheld power tool according to embodiments of the invention;

Fig. 6 is a top-view cutaway drawing of an alternative embodiment of the handheld power tool of Fig. 5;

Fig. 7 is a side-view drawing of the handheld power tool of Fig. 4; Figs. 8 and 9 are end-view drawings of handheld power tools according to embodiments of the invention;

Fig. 10 is a side-view perspective line drawing of the handheld power tool of Fig. 4, with a powerhead assembly portion partially disassembled to show internal structure;

Fig. 11 is an end-perspective view line drawing of the handheld power tool of Fig. 4, with a powerhead assembly portion partially disassembled to show internal structure:

Fig. 12 is a side elevational view of an embodiment of the handheld power tool of the present invention;

Fig. 13 is a side elevational view of an additional embodiment of the handheld power tool of the present invention; Fig. 14 is a side elevational view of a further embodiment of the handheld power tool of the present invention;

Fig. 15 is an exploded line drawing of the drive mechanism of the handheld power tool according to embodiments of the invention; and

Fig. 16 is a side elevational view of an embodiment of the handheld power tool with a spring biased guard. Detailed Description

As shown in the figures, a handheld power tool is depicted generally at 10.

According to embodiments of the present invention, the handheld power tool 10 may include a generally cylindrical motive source 12, a powerhead assembly couplable at one end of the motive source 12, and a rotatable implement 16 mounted to the powerhead assembly portion.

Motive source 12 preferably functions as an enclosure or housing 11 for internal energizing components (not shown) for imparting rotating motion to the rotatable implement 16. A handle portion 17, comprising the external margin of the motive source 12 housing is preferably shaped to accommodate a user's hand. The user may grasp the tool 10 as shown in Fig. 4. Any suitable material, such as metal or plastic, may be used to form the housing 11 of the motive source 12. For instance, motive source 12 shown in Figs. 4-7 is formed from metal.

As depicted in Figs. 12 - 14, the motive source 12 may be a pneumatic motive source 12a, having a pneumatic coupler 13 a, an electric motive source 12b and powered from a 110 VAC outlet and having an electric wire 13b for coupling thereto, and may be an electric motive source 12c and powered by a rechargeable DC battery pack 13 c.

The handle portion 17 is shown to include indentations 20 to facilitate secure gripping of handle portion 17. Other features may additionally or alternatively be used, such as a rubber sleeve and/or a differently textured surface, to facilitate electrical insulation and/or secure gripping of handle portion 17 or any other region of motive source 12.

The motive source 12 preferably includes a trigger 36 that is pivotally mounted on pivot 37. The trigger 36 is preferably biased in the neutral state, as depicted in Fig. 4. Rotating the trigger 36 towards the housing 11 causes the underside margin of the trigger 36 to compress the actuator 39. In compression, actuator 39 serves to actuate the internal energizing components of the motive source 12, thereby imparting rotary motion to the implement 16. In the embodiment of Figs. 12-14, the trigger 36 terminates at the distal end thereof in finger sized hook 41. The hook 41 assists in preventing the hand of the user from advancing to come into contact with the implement 16. Powerhead assembly 14 is shown coupled to one end of motive source 12 and serves as a mount for rotatable implement 16. Powerhead assembly 14 may also house internal components, as described in more detail below. As shown in Figs. 4-6, powerhead assembly 14 may radially extend outward relative to the surface of motive source 12, such as to distinguish the powerhead assembly 14 from motive source 12. Distinguishing powerhead assembly 14 from motive source 12 may provide safety to a user by delineating the boundary of handle 17, which is spaced from rotatable implement 16.

As also shown in Fig. 5, powerhead assembly 14 may rotatably support rotatable implement 16, such as an abrasive disc, in an "inline" position extending from the end of powerhead assembly 14, the plane of the rotatable implement 16 intersecting the longitudinal axis 15 of the motive source 12 and the center 19a of the axis of rotation 19 of the rotatable implement 16 being coincident with the longitudinal axis 16. In other words, the rotatable implement 16 is generally linear with the longitudinal axis 15 of the cylindrical motive source 12, rather than being offset therefrom as noted in the prior art of Figs. 1-3.

With reference to Fig. 5, powerhead assembly 14 is shown to include two shoulders 22 and 24 separated by a slot 26 in which rotatable implement 16 is mounted. Shaped depressions 27 are formed in powerhead assembly 14 adjacent rotatable implement 16 and distal to motive source 12. As can be seen from the two embodiments in Figs. 5 and 6, different shaped depressions 27 may be formed to have different depths, angles of inclination, and degree of tapering. Shaped depressions 27 may provide a surface on which to support and slide tool 10 along a workpiece as it engages in cutting or grinding. The different embodiments of shaped depressions shown in Figs. 5 and 6 may provide different types of supporting and sliding performance.

Powerhead assembly 14 may facilitate precision, accuracy, and stability while the tool is deployed and rotatable implement 16 is used to cut and/or grind a workpiece. For example, outside edges 28 and 30 of powerhead assembly 14 (which also form the outside edges of shoulders 22 and 24) provide generally flat surfaces that can be used to abut a guide surface or fence parallel to an intended cut. Thus, outside edges 28 and 30 can promote straight cuts when the tool is used in coordination with a fence, such as by pressing the tool against the fence and drawing the tool along the surface of the workpiece. As shown in Fig. 5, the surface of rotatable implement 16 is offset from edge 28 by a distance indicated as X, and offset from edge 30 by a distance indicated as Y. As such, in practice, a user can orient a fence or straight edge the distance X or Y from an intended cut, and then abut edge 28 or 30 against the fence and direct tool 10 longitudinally along the straight edge to produce a straight cut. In the embodiment shown in Figs. 4-9, the distance X from rotatable implement 16 to outside edge 28 is the same as the distance Y from rotatable implement 16 to outside edge 28. However, other embodiments may be configured such that the distances X and Y are different. In other words, in other embodiments, the rotatable implement may not be supported in a configuration such that the rotatable implement is not coplanar with a central axis of the cylindrical motive source 12, but may be slightly offset therefrom but still parallel thereto. In still other embodiments, the configuration of the powerhead assembly 14 may be such that distances X and/or Y can be selectively changed, such as by sliding out an extender member from power assembly 14 or attaching an extension member to power assembly 14. Note that the lengths X and Y can be different while still maintaining rotatable implement 16 inline with motive source 12. Embodiments in which length X differs from length Y may provide convenience to a user. For example, in situations where two different intended cuts correspond to the unique distances X and Y from a fence, both intended cuts can be made with tool 10 without repositioning the fence. This can be accomplished merely by rotating tool 10 by 180 degrees such that the opposite outside edge abuts the fence which switching between intended cuts.

Moreover, shoulders 22 and 24 may facilitate precision, accuracy, and stability by providing lateral stability while cutting. The lateral stability imparted by shoulders 22 and 24 may counteract any tendency to twist that a rotary cutting tool may exhibit. Ends 32 and 34 of shoulders 22 and 24, respectively, may support tool 10 from the workpiece on both sides of rotatable implement 16 as tool 10 cuts in a longitudinal direction. Rounded ends 32 and 34 may initially be brought into contact with a workpiece as rotatable implement 16 cuts into the workpiece. Once in contact with the workpiece, ends 32 and 34 may support tool 10 on both sides of rotatable implement 16 by sliding along the workpiece during the cut. With reference to Fig. 7, a distance Z between the outer surface of ends 32 and the bottom of the peripheral edge (i.e. diameter) of rotatable implement 16 may define a cut depth. The cut depth may he set or modified by changing distance Z, either by using a different sized rotatable implement 16 or modifying the size of ends 32. Ends 32 can be formed in a variety of different sizes to facilitate different cut depths. In some examples, different shoulder pieces are provided to allow different cut depths. Optionally, although not shown, some embodiments may include additional structure configured to allow selective adjustment of the cut depth, for example by supporting the powerhead assembly 14 at a desired height relative to a workpiece surface.

Another example of how powerhead assembly 14 facilitates precision, accuracy, and stability occurs during grinding. Shoulder 22 or 24 can be used as a pivot point when bringing rotatable implement 16 into contact with a workpiece. Using shoulder 22 or 24 as a pivot point allows a user to more precisely introduce rotatable implement 16 to the workpiece by pivoting tool 10 about the pivot point.

Tool 10 may be powered to rotate rotatable implement 16 by any suitable means, including pneumatically, electrically, mechanically, and so forth. For example, the embodiment shown in Fig. 12 is pneumatic and, thus, powered by compressed air. Compressed air is introduced to a pneumatic cylinder (not shown) in motive source 12a via an inlet port 38 air boss 13 a. The pneumatic cylinder converts the energy contained in the compressed air into rotational motion of an output shaft 50, which is shown in Figs. 10 and 11 and rotatable implement lόussed in more detail below. In examples where tool 10 is powered by electricity, as depicted in Figs. 13 and 14, an electric motor is typically included in motive source 12 to drive output shaft 50, the motive source 12b is AC and receiving its power from 110 VAC cord 13b. The motive source 12c is DC, receiving its power from rechargeable battery 13 c. In other examples, chemical means, such as gasoline, may be used in conjunction with an engine in motive source 12 to mechanically drive output shaft 50.

Powered rotation of rotatable implement 16 may occur selectively by pivoting a trigger 36 coupled to motive source 12. Tool 10 may be configured to rotate rotatable implement 16 at a desired rate. For example, the pictured embodiment is operable at approximately 22,000 revolutions per minute, but may also be configured to rotate rotatable implement 16 faster or slower depending on a given application. Other embodiments may be configured to rotate a rotatable implement at any desired rate.

With reference to Figs. 10 and 11, tool 10 is shown to include various internal components to drive rotation of rotatable implement 16. The internal components may be accessible by removing or loosening fasteners 40, which secure removable shoulder 22 and 24 in a covering position. Fasteners 40 may be any suitable fastener, including screws or bolts. A complimentarily configured tool, such as an Allen wrench or blade screwdriver, may be used to tighten or loosen fasteners 40.

To stabilize tool 10 during tightening or loosening of fasteners 40, a port 42 may be provided. For example, in an embodiment of tool 10 shown in Fig. 9, port 42 is provided in rounded end 34, although the location of port 42 could be provided in rounded end 32 or elsewhere on tool 10. A user can insert a tool, such as a pin, into port 42 to stabilize tool 10 when applying torque to fasteners 40 to tighten or loosen them. For example, a pin inserted into port 42 may engage with an axle that supports the rotatable implement 16. Such a configuration may prevent rotation of the rotatable implement 16 when a fastener 42 is turned, allowing the fastener to be tightened or loosened.

As discussed above, a power source such as a pneumatic cylinder may drive rotation of output shaft 50. In the embodiment shown in Figs. 10 and 11, output shaft 50 includes a helical gear 52 intermeshed with a bevel gear 54 disposed on drive shaft 80. (See also Fig. 15) Bevel gear 54 may be coupled to the belts 56 configured to transmit torque to a driven shaft 58. Alternatively, a direct gear drive may be used by incorporating the bevel gear 54 with the drivenshaft 58. The bevel gear may be formed integral with or operably coupled to a respective axle half 90, 92 (as described below). A respective toothed belt 56 resides in a groove 59 defined in the interior surface of each of the shoulders 20, 22. Each of the belts 56 engages a respective toothed gear 82 disposed on the drive shaft 80. The drive shaft 80 is supported in a pair of bearings 84.

Driven shaft 58 includes the two axle halves 90, 92, couplable by a bolt 94. Each of the halves 90, 92 includes a bearing 96, a toothed drive gear 98 (engagable by a respective belt 56), and a mandrel 100. In assembly, The bolt 94 passes through the bore defined in the bearing 96, the bore defined in the gear 98 and the bore defined in the mandrel 100 of axle half 92 and then through the mandrel of the implement 16. The arbor of the rotatable implement 16 is aligned with the bores 102 defined in the components 96, 98, and 100. The bolt 94 then carries through the components 100, 98, 96 of the axle half 90, through the arbor of the rotatable implement 16 and threads into threads defined in a one of the shoulders 20, 22. This assembly holds the implement 16 in place in the tool 10. Tightening the bolt 94 acts to compressively capture the arbor of the rotatable implement 16 between the faces 104. Such compression is sufficient to rotate the arbor of the rotatable implement 16 even when the arbor of the rotatable implement 16 is working on a workpiece. Effectively, the axle 58 is a two piece axle held together by mean dot the bolt 98. An advantage of such arrangement is that the rotatable implement 16 may be readily replaced simply by removing the bolt 98. Alternative internal components and configurations may be used to drive rotation of rotatable implement 16 from the torque supplied by output shaft 50. In the embodiment of Figs. 12-14 and 16, the tool 10 includes a rotatable guard 108. The guard 108 is in two configurations as respectively indicated in Figs 12-14 and 16. In Figs. 12-14, the guard 108 is rotatable about axis 19 and is frictionally held in the desired position as indicated variably in Figs. 12-14. The user so positions the guard 108 prior to performing the operation on the workpiece 110. In the embodiment of Fig. 16, the guard 108 is freely rotatable about the axis 19 and is biased by a spring 112 that biases the guard 108 in a position substantially covering the exposed arc of the implement 16. The spring 112 in Fig. 16 illustrates the return-function of the spring, and not an actual spring mounted to the tool 10, of course.

Rotatable implement 16 may take a variety of forms. In the examples shown in Figs. 4-11, rotatable implement 16 includes two opposing abrasive surfaces 70 defined by a non- toothed peripheral edge 72. In other examples, rotatable implement 16 may comprise a toothed blade with or without one or more abrasive surfaces. Rotatable implement 16 may also take the form of a brush, or any suitable configuration. Tool 10 may be provided with a guard 102, as depicted in Figs. 12-14, adjacent to rotatable implement 16 to protect inadvertent contact of the rotating rotatable implement 16, such as by a user or by other objects that may otherwise obstruct or interfere with the rotation of rotatable implement 16 during operation of the tool 101. Such a guard 102 may be configured to rotate as tool 10 is brought into contact with a workpiece 110, as illustrated in Figs. 12- 14), for example to initiate a cut or to grind the workpiece 110. As depicted in Fig. 16, the guard 102 may be biased in the disposition substantially covering the implement 16 by means of a spring 112 having a first end coupled to the guard 102 and a second end anchored to the shoulder 21, 22. Alternatively, the spring 112 may be a coil spring mounted about the axis of the rotatable implement 16. Other embodiments may include various other springs, combination of springs, or other structures capable of biasing the guard 102. The guard 102 may be positioned on both sides of tool 10 adjacent rotatable implement 16, on only one side, or a guard 102 may not be included at all.

Moreover, tool 10 may be provided with a dust collection system (not pictured) for reducing the amount of dust created while operating on a workpiece with tool 10. Reducing the amount of dust may limit the amount of dust inhaled by a user and reduce dust accumulation on surrounding surfaces. Dust collection systems for power tools are known in the art and any suitable dust collection system may be used. A collection receptacle with an inlet, such as a bag with an opening, that is subject to negative pressure, such as via a vacuum, may serve as a suitable dust collection system.

The handheld power tool disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in a particular form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties rotatable implement disclosed herein. Where the disclosure or subsequently filed claims recite "a" or "a disclosure or claims may be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Applicant reserves the right to submit claims directed to certain combinations and subcombinations that are directed to one of the disclosed inventions and are believed to be novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of those claims or presentation of new claims in that or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present handheld power tool disclosure.

Claims

What is claimed is: 1. A powerhead for a handheld power tool, comprising: a powerhead assembly , the powerhead assembly being operably couplable to a hand held motive source; the powerhead assembly having a rotatable implement, the implement being selectively rotated by the motive source when the motive source is operably coupled to the powerhead assembly, the implement further being rotatable about an implement axis, the implement axis being disposed transverse to a powerhead assembly longitudinal axis, the implement axis intersecting the powerhead assembly longitudinal axis; and a rotatable guard structured to at least partially cover the rotatable instrument.

2. The powerhead of claim 1 being powered by a motive source selected from a list consisting of pneumatic, AC electric and DC electric.

3. The powerhead of claim 1 , the rotatable implement being borne on a two piece axle.

4. The powerhead of claim 1 , power to the rotatable implement being transferred by means of at least one toothed belt.

5. The powerhead of claim 1 , including power transmission means being a drive shaft coupled by at least one belt to a driven shaft, the implement being disposed on the driven shaft.

6. The powerhead of claim 1 , including an actuation trigger, the trigger having a distal end terminating in a hook.

7. The powerhead of claim 1 , including power transmission means, the power 5 transmission means being captured between two opposed shoulders.

8. A powerhead, comprising: powerhead assembly means, the powerhead assembly means for being operably coupled to a hand held motive source means; o the powerhead assembly means having a rotatable implement means, the implement means for being selectively rotated by the motive source means when the motive source means is operably coupled to the powerhead assembly means, the implement means further being rotatable about an implement axis means, the implement axis means for being transversely disposed to a powerhead assembly longitudinal axis, the implement axis 5 intersecting the powerhead assembly longitudinal axis; and a guard for rotating about the implement axis.

9. The powerhead of claim 8 being powered by motive source means selected from a list consisting of pneumatic, AC electric and DC electric. 0

10. The powerhead of claim 8, including the rotatable implement means for being borne on a two piece axle.

11. The powerhead of claim 8, power to the rotatable implement means for being 5 transferred by means of at least one toothed belt.

12. The powerhead of claim 8, including power transmission means being drive shaft means for being coupled by at least one belt to a driven shaft, the implement means for being disposed on the driven shaft means.

13. The powerhead of claim 8, including actuation trigger means, the trigger means having a distal end terminating in hook means.

14. The powerhead of claim 8, including power transmission means, the power transmission means for being captured between two opposed shoulders.

15. A handheld power tool, comprising: a powerhead assembly, the powerhead assembly being operably coupled to a hand held motive source; the powerhead assembly having a rotatable implement, the implement being selectively rotated by the motive source, the implement further being rotatable about an implement axis, the implement axis being disposed transverse to a power tool longitudinal axis, the implement axis intersecting the power tool longitudinal axis.

16. The hand held powered tool of claim 15 providing power by means of a motive source selected from a list consisting of pneumatic, AC electric and DC electric.

17. The hand held powered tool of claim 15, the rotatable implement being borne on a two piece axle.

18. The hand held powered tool of claim 15, power to the rotatable implement being transferred by means of at least one toothed belt.

19. The hand held powered tool of claim 15, including power transmission means being a drive shaft coupled by at least one belt to a driven shaft, the implement being disposed on the driven shaft.

20. The hand held powered tool of claim 8, including an actuation trigger, the trigger having a distal end terminating in hook.

21. The hand held powered tool of claim 15, including power transmission means, the power transmission means being captured between two opposed shoulders.

22. A method of forming a powerhead for a hand held power tool, comprising: forming a powerhead assembly and operably coupling the powerhead assembly to a hand held motive source; including a rotatable implement in the powerhead assembly, selectively rotating the implement by means the motive source when the motive source is operably coupled to the powerhead assembly, rotating the implement about an implement axis, and disposing the implement axis transverse to a powerhead assembly longitudinal axis, and effecting intersection of the implement axis with powerhead assembly longitudinal axis.

23. The method of claim 22 including providing power by means of a motive source selected from a list consisting of pneumatic, AC electric and DC electric.

24. The method of claim 22, including bearing the rotatable implement on a two piece axle.

25. The method of claim 1 , including transferring power to the rotatable implement by means of at least one toothed belt.

26. The method of claim 22 including effecting power transmission by means of a drive shaft coupled by at least one belt to a driven shaft and disposing the implement on the driven shaft.

27. The method of claim 26, including providing an actuation trigger and terminating a distal end of the trigger in hook.

28. The method of claim 22, including providing power transmission means and capturing the power transmission means between two opposed shoulders.