Interchangeable implement system for power tools

Abstract: A power tool system (1) having detachable and interchangeable implements (14) and driving sources (10). The interchangeable implements (14) and driving sources (10) use a housing (16) having common mating interface to selectively assemble a power tool having the desired characteristics. A latch (18) is used to hold a selected implement (14) and driving source (10) in functional engagement. An adjustable bale handle (60) provides a comfortable handhold for various configurations of the interchangeable implements (14).

Description: The present invention is directed to power tools. In particular, the present invention is directed to a power tool having a system of detachable and interchangeable implements. Such an attachment system is known for example from US-A-5,033,552. The term "power tool" includes hand-held power tools such as hedge trimmers and chain saws, as well as mechanisms which are not hand-held but whose operation is controlled by the hands of a user, e.g., lawn mowers and grinders. In order to perform a desired task using a power tool, it is important to select a power tool that has the proper configuration and capacity for accomplishing the task efficiently. The size and shape of the working tool, the speed and power of the driving mechanism, as well as the comfort of the user must always be considered. Conventionally, a user selects the appropriate tool from a collection of similar devices each having different characteristics. For example, in order to select an appropriate hand-held, powered hedge trimmer, the user must make a number of choices: whether to use a single or a double edge cutting blade, the length of the cutting blade, the shape of the cutting teeth, whether driving power should come from an electric motor or an internal combustion engine, the amount of power and speed required for driving the cutting blade, etc. Given all the permutations of these characteristics, a large collection of variously configured hedge trimmers would be required. Generally, the cost of purchasing, maintaining and storing such a large collection of hedge trimmers is prohibitive. It is much more common for a user to own a single hedge trimmer that is used in every situation, regardless of how well suited the hedge trimmer is to that particular situation. Under these circumstances, the efficiency and/or adequacy of the tool is often insufficient. It is also conventional for a power tool to be of fixed configuration. Specifically, it is common for each tool to have a single relative arrangement of the handle, power source and working tool. One disadvantage of such a fixed arrangement is that the user is not able to adjust the power tool for comfortable operation. In accordance with an embodiment of the invention there is provided an attachment system for connecting a driven implement to a driving source having the features as set forth in claim 1. The accompanying drawings illustrate an embodiment of the invention, and, together with the general description given above and the detailed description given below, serve to explain the principles of the invention, of which:- Figure 1 is a schematic illustration of a power tool according to the present invention having a main body matingly engaging a housing of a working implement, and a latch assembly in a first, unlatched, position; Figure 2 is a schematic illustration of the power tool shown in Figure 1, with the latch assembly in a second, latched, position; Figure 3 is a perspective view of the latch assembly shown in Figure 1; Figure 4 is a perspective view of a gear case portion of the power tool main body according to the present invention; Figure 5 is a perspective view of a working implement according to the present invention; Figure 6 is an exploded view of the working implement shown in Figure 5; Figures 7A and 7B are perspective views of an auxiliary handle for a power tool according to the present invention; Figure 8 is a perspective view of a detail of a main body of a power tool according to the present invention; Figure 9 is a partial cross-section view of a power tool according to a preferred embodiment of the present invention; Figure 10 is a bottom plan view of a main body of the preferred embodiment of the present invention illustrated in Figure 9; Figure 11 is a detail view of a clutch hub according to the preferred embodiment of the present invention illustrated in Figure 9; Figure 12 is a side elevation view of a working implement according to a preferred embodiment of the present invention; Figure 13 is a top plan view of the working implement according to the preferred embodiment of the present invention illustrated in Figure 12; Figure 14 is a cross-section view taken along line XIV-XIV in Figure 13; and Figure 15 is a detail view of a drive spud according to the preferred embodiment of the present invention illustrated in Figure 12. A hand-held power tool (1) is shown in Figures 1 and 2. The power tool (1) includes a main body (10) supporting and enclosing a driving source such as an electric motor or an internal combustion engine (not shown). The main body (10) additionally supports conventional controls and auxiliary systems (not shown) for operating the driving source. The main body (10) also provides at least one means for a user's hands to hold the power tool (1). A working implement (14) is operably connected to the driving source. For the sake of illustration, a double edge hedge-trimming implement is generically illustrated throughout the drawings. However, in accordance with the present invention, implements of different types and/or characteristics may also be used in connection with the main body (10). One example of a different type of implement is a rotary saw, as opposed to a reciprocating saw. A housing or cassette (16) connects the implement (14) to the main body (10). The cassette (16) provides a physical connection for supporting the mass of the implement (14) with respect to the main body (10), as well as houses a driving connection between the driving source and the implement (14). The connection between the cassette (16) and the main body (10) provides a detachable interface such that different types and/or sizes of working implements may be readily connected to the main body (10) by different cassettes (16). Specifically, the cassette (16) provides a single type of connection for attaching a range of implements having different characteristics (e.g., type, size, etc.) to the same main body (10). Similarly, the cassette (16) enables the implement (14) to be connected to a range of main bodies (10) having different characteristics (e.g., driving source type, power output, etc.). According to the present invention, a large collection of power tools is provided by interchangeably connecting small numbers of main bodies (10) and cassettes (16). Thus, a user is able to select the appropriate power tool for a desired task without the expense of purchasing, maintaining and storing a wide range of individual power tools. According to a preferred embodiment of the present invention, as illustrated in Figures 1-3, a latch assembly (18) is used to secure and release the cassette (16) with respect to the main body (10). The latch assembly (18) is pivotally mounted with respect to the gear case (12) at a pair of pivot points (20A) and (20B) on opposite sides of the gear case (12). Spacers (19), see Figure 1, are interposed between the latch assembly (18) and bosses( 20A') and (20B') on the gear case (12). This provides electrical insulation for the latch assembly (18) from the gear case (12), drive mechanism, and blades (50A,50B) in the event the insulation of the power cord (for an electric powered version) is severed accidentally while operating the power tool (1). The spacers (19), which are preferably made of plastic, also provide a durable, low friction bearing surface for the latch assembly (18) to pivot on, as opposed to having the latches wearing into the bosses (20A',20B') on the gear case (12) when pivoted. The latch assembly (18) includes a pair of latch arms (22A) and (22B) extending substantially parallel to one another and transversely from a common grip (24) to a corresponding one of the pivot points (20A,20B). According to the preferred embodiment of the present invention, each of the pivot points (20A,20B) comprises one of the two bosses (20A',20B') on the gear case (12), respectively, and one of two holes (20A") and (20B"), respectively, on the latch arms (22A,22B). Although the bosses (20A',20B') are shown formed on the gear case (12) and the holes (20A",20B") are shown formed in the latch arms (22A,22B), the shafts (20A',20B') may alternatively be formed on the latch arms (22A,22B) and the holes (20A",20B") formed in the gear case (12). The latch arms (22A,22B) include respective cam surfaces (26A) and (26B) for engaging corresponding rollers (28A) and (28B) mounted for rotation about posts on opposite sides of the cassette (16). The cam surfaces (26A,26B) and the rollers (28A,28B) comprise overcentre mechanisms such that as the latch assembly (18) is elastically deformed during pivoting with respect to the gear case (12). Specifically, as the latch assembly (18) is pivoted from a relaxed (i.e., un-deformed) state to a first position, the cam surfaces (26A,26B) engage the rollers (28A,28B) so as to elastically elongate that portion of the latch arms (22A,22B) extending from the pivot points (20A,20B) to the cam surfaces (26A,26B). Upon further pivoting the latch assembly (18) to a second position, the cam surfaces (26A,26B) remain engaged with the rollers (28A,28B); however, the latch arms (22A,22B) are elongated to a lesser degree. As is known with overcentre mechanisms, the latch arms (22A,22B) tend to be biased away from the first position of greatest elongation to either the second position of reduced elongation, or to a third position wherein the latch arms (22A,22B) are in the relaxed state. Thus, the latch assembly (18) secures and releases the cassette (16) with respect to the gear case (12) simply by pivoting the latch assembly (18) with respect to the gear case (12), i.e., without the need of any additional tools or fasteners. By virtue of the grip (24) being spaced apart from the pivot points (20A,20B) a greater distance than the cam surfaces (26A,26B) are spaced apart from the pivot points (20A,20B), a mechanical advantage is realized. Figure 4 shows the surface of the gear case (12) that interfaces with the cassette (16). In a preferred embodiment of the present invention, a first clutch part, or clutch hub, (30) is driven by the driving source and is accessible from the exterior of the gear case (12). The clutch hub (30) provides a driving force that is transferred through the cassette (16) to operate the implement (14). Also projecting from the gear case (12) are positioning pins (32A) and (32B) for locating the cassette (16) with respect to the gear case (12). As will be described further with reference to Figure 5, the pins (32A,32B) are received in corresponding holes in the cassette's cover plate (40). Although the pins (32A) and (32B) are shown as part of the gear case (12) and the holes are shown as part of the cassette (16), the pins may alternatively be attached in the cassette (16), and the holes formed in the gear case (12). Figure 5 shows the surface of the cover plate (40) that interfaces with the gear case (12). The pins (32A,32B) are matingly received in holes (34A) and (34B), and the clutch hub (30) matingly engages a second clutch part, or drive spud, (72). Figures 5 and 6 show a preferred embodiment of the present invention having a cassette (16) for connecting a reciprocating, double edge hedge trimming implement (14) to the gear case (12). The cassette (16) includes a shell (38)and the cover plate (40), and defines an interior volume. The shell (38) supports the mass of the implement (14) that is retained by means of two fasteners (42A) and (42B) and two nuts (48A) and (48B) secured to a clamping plate (46), which is trapped between the shell (38) and the cover plate (40). Anti-friction washers (44A) and (44B) are interposed between respective ones of the fasteners (42A,42B) and the blades (50A,50B) for improving the relative sliding action and reducing wear of the implement (14) with respect to the cassette (16). Different clamping plates (46), fasteners (42A,42B), and nuts (48A,48B) may be used to support implements (14) having different characteristics within the housing (16). According to the preferred embodiment of the present invention, the implement (14) includes two stacked blades (50A) and (SOB) that are longitudinally reciprocated with respect to one another. A blade support (52) extends along the length of the blades (50A,50B) to maintain the relative relationship between the blades (50A,50B) at the distal end thereof. The blades (50A,50B) and blade support (52) operate in a conventional manner. The blades (50A,50B) and the blade support (52) are interposed between the clamping plate (46) and the shell (38), and extend outward from the interior of the cassette (16) through an opening between the shell (38) and the cover plate (40). The relative configuration of the clamping plate (46) with respect to both the implement (14) and the cassette (16) ensures only the desired relative motion of the implement (14) with respect to the housing (16). Also mounted in the interior of the shell (38) is the drive spud (72) for matingly engaging the clutch hub (30) and for transferring motion from the clutch hub (30) to the blades (50A,50B). According to the preferred embodiment of the present invention, the drive spud (72) engages a blade driver (not shown) that is rotates about the same axis of rotation as the clutch hub (30) and the drive spud (72). The blade driver includes eccentrics (not shown) that matingly engage the blades (50A,50B) in a conventional manner for reciprocating the blades 950A,50B) with respect to one another. The drive spud (72) may also include a bearing (55) for reducing heat and wear. The drive spud (72), clutch hub (30), blade driver, and the eccentrics may all also be made of a material capable of acting as its own bearing surface. The cover plate (40) includes the aperture (36) for the drive spud (72) to protrude from to engage the clutch hub (30), as well as the holes (34A,34B) for receiving the positioning pins (32A,32B). When the cassette (16) is to be engaged with the gear case (12), the pins (32A,32B) are aligned with the holes to prevent relative lateral movement between the cassette (16) and the gear case (12) The latch assembly (18) is subsequently pivoted to the second position described above to hold the cassette (16) against the gear case (12). Concurrently, the drive spud (72) passes through the aperture (360 and matingly engages the clutch hub (30) for conveying movement from the driving source, through the cassette (16), to the implement (140. The reverse procedure is used for disconnecting the cassette (16) from the gear case (12). According the present invention, a common interface between cassette (16) and gear case (12) enables a wide range of implements (140 and main bodies (10) to be interchangeably connected. According to another aspect of the present invention as shown in Figures 7 and (8), a bale handle (60) may be adjustably attached to the main body (10). The adjustable bale handle (60) enables a user to hold the power tool (1) comfortably after interchanging the implements (14) or after the user repositions themselves with respect to the workpiece. According to a preferred embodiment of the present invention, the bale handle (60) is fastened to the main body (10) for pivotal movement about an axis. A detent system comprising at least one projection (62) and at least one recess (64) are matingly engageable for holding the bale handle (60) at a desired angular position with respect to the main body (10). According to the preferred embodiment illustrated in Figures 7 and 8, the bale handle (60) includes a plurality of the projections (62') and recesses (64') arranged so as to at least partially circumscribe the pivot axis, and the main body (10) includes a plurality of the recesses (64") (for engaging projections (62')) and projections (62") (for engaging recesses (64')) arranged so as to at least partially circumscribe the pivot axis. For each position of the bale handle (60) relative to the main body (10), at least one of the projections (62',62") is matingly received in one of the recesses 964',64"), respectively. Elastically deforming the bale handle (60) so as to displace the projections (62) in a direction parallel to the axis and away from the recesses (64) enables the bale handle (60) to be angularly reoriented. Aligning and matingly engaging a different combination of the projections (62) with recesses (64) enables the bale handle (60) to be retained at a different angular position with respect to the main body (10). A lock may be used to releasably secure the detent system. According to a preferred embodiment, the lock may comprise cooperatively engaging threaded male and female members that, when relatively tightened, hold the projections (62) in the recesses (64). According to a preferred embodiment, the range of angular adjustment of the bale handle (60) with respect to the main body (10) is constrained by at least one stop (66) that extends axially from the main body (10) into at least one arcuate groove (68) in the bale handle (60). The arcuate groove (68) partially circumscribes the pivot axis. The location and length of the arcuate groove (68) defines the permissible range of motion for the bale handle (60) relative to the main body (10). Although the projections (62) have been illustrated as being formed on the bale handle (60), and the recesses (64) have been illustrated as being formed on the main body (10), it is alternatively envisioned that the projections (62) may be formed on the main body (10) and the recesses (64) may be formed on the bale handle (60). Similarly, although the stop (66) has been illustrated as being formed on the main body (10) and the arcuate groove (68) has been illustrated as being formed on the bale handle (60), it is alternatively envisioned that the stop (66) may be formed on the bale handle (60) and the arcuate recess may be formed on the main body (10). Figures 9-15 are directed to a preferred embodiment of the present invention. According to this preferred embodiment, a driving force is transmitted through the clutch hub (30) and the drive spud (72). The clutch hub (30) and the drive spud (72) are configured and arranged to cooperatively engage one another, thus facilitating transmission of the driving force from the main body (10) to the implement (14). The dimensions according to preferred embodiments of the present invention are indicated with on the Figures and correspond with the reference numerals in Table 1. Ref. No. Description Preferred Range Preferred Example 101 Diameter of positioning pins 32A,32B 4 - 8 mm 6.00 mm 102 Front to Back distance between gear center pin 70 and positioning pins 32A,32B 55 - 75 mm 65.00 mm 103 Distance from center line between positioning pins 32A,32B to each of the positioning pins 32A,32B 25 - 35 mm 30.25 mm 104 Distance between positioning pins 32A,32B 50 - 70 mm 60.50 mm 105 Angle of drive tooth for clutch hub 30 30 - 60° 40° 106 Radius of drive tooth outside corner for clutch hub 30 1 - 2 mm 1.50 mm 107 Radius of inside surface of drive tooth for clutch hub 30 2 - 3 mm 2.50 mm 108 Diameter of center hole of clutch hub 30 5 - 7 mm 6.06 mm 109 Radius of drive tooth inside corner for clutch hub 30 0.5 - 1.5 mm 1.00 mm 110 Angle between drive teeth for clutch hub 30 30 - 60° 45° 111 Diameter between drive teeth for clutch hub 30 10 - 20 mm 14.00 mm 112 Maximum distance of recess of drive teeth for clutch hub 30 25 - 35 mm 29.00 mm 113 Vertical distance from end of gear center pin 70 to the locating ribs on the gear case 12 25 - 35 mm 29.42 mm 114 Horizontal distance from gear center pin 70 to the rear locating ribs on the gear case 12 35 - 55 mm 45.00 mm 115 Horizontal distance from gear center pin 70 to the front locating ribs on the gear case 12 70 - 95 mm 82.50 mm 116 Radius of arc that latch assembly 18 swings through about pivot points 20A,20B 35 - 55 mm 45.40 mm 117 Horizontal distance from pivot points 20A,20B to initial position of the arc for latch assembly 18 30 - 50 mm 37.10 mm 118 Vertical distance from pivot points 20A,20B to initial position of the arc for latch assembly 18 20 - 35 mm 26.15 mm 119 Horizontal distance from pivot points 20A,20B to final position of the arc for latch assembly 18 20 - 40 mm 30.35 mm 120 Vertical distance from pivot points 20A,20B to final position of the arc for latch assembly 18 25 - 40 mm 33.76 mm 121 Horizontal distance from gear center pin 70 to pivot points 20A,20B 5 - 15 mm 10.40 mm 122 Vertical distance from pivot points 20A,20B to locating ribs on gear case 12 15 - 30 mm 23.18 mm 123 Diameter of opening in gear case cover 20 - 40 mm 28.50 mm 124 Inside distance between latches 22A,22B 70 - 110 mm 88.70 mm 201 Diameter of holes 34A,34B 4 - 8 mm 6.00 mm 202 Front to back distance between centers of aperture 36 and holes 34A,34B 50 - 80 mm 65.00 mm 203 Side to side distance from center of aperture 36 to centers of holes 34A,34B 25 - 35 mm 30.25 mm 204 Distance between centers of holes 34A,34B 50 - 70 mm 60.50 mm 205 Angle of recess between drive teeth for drive spud 72 30 - 60° 50° 206 Angle of driven teeth for drive spud 72 30 - 60° 40° 207 Outside comer radius of driven teeth for drive spud 72 1 - 2 mm 1.50 mm 208 Outside diameter of driven teeth for drive spud 72 25 - 35 mm 27.60 mm 209 Inside diameter of driven teeth for drive spud 72 8 - 18 mm 13.00 mm 210 Inside comer radius of driven teeth for drive spud 72 0.5 - 1.5 mm 1.00 mm 211 Vertical distance from cover plate 40 to bottom of shell 38 at the gear center pin 70 location 25 - 45 mm 34.84 mm 212 Horizontal distance from center of drive spud 72 to back of cover plate 40 40 - 65 mm 53.20 mm 213 Horizontal distance from center of drive spud 72 to front of cover plate 40 90 - 160 mm 127.03 mm 214 Horizontal distance from center of drive spud 72 to sides of cover plate 40 at position of rear locating ribs on the gear case 12 after assembly 30 - 50 mm 41.00 mm 215 Horizontal distance from center of drive spud 72 to sides of cover plate 40 at position of front locating ribs one the gear case 12 after assembly 30 - 50 mm 41.30 mm 216 Vertical distance from cover plate 40 to centers of rollers 28A,28B 10 - 20 mm 14.00 mm 217 Horizontal distance from center of drive spud 72 to centers of rollers 28A,28B 20 - 40 mm 29.00 mm 218 Diameter of rolling surfaces of rollers 28A,28B 16 - 21 mm 18.50 mm 219 Width of rolling surfaces of rollers 28A,28B >2 mm 3.88 mm 220 Distance between rolling surfaces of rollers 28A and 28B 80 - 110 mm 93.02 mm An advantage of the embodiments described above is that they provide a power tool that may be readily selectively configured by the user for optimum efficiency and ease of operation. Also, these embodiments provide an arrangement for mating a driving source with a detachable working implement selected from a range of interchangeable tools. Another advantage of these embodiments is that they provide a mating arrangement for connecting a driving source with a detachable working implement that does not require additional tools to make the connection. In addition, these embodiments provide an arrangement for interchangably supporting a working implement with respect to a driving source, and for transferring power from the driving source to the working implement.

Claims: An attachment system for connecting a driven implement (14) to a driving source including a power take-off (30) accessible with respect to a main body (10), the attachment system comprising:- a housing (16) adapted for supporting the driven implement (14) and for matingly engaging the main body (10); a drive transfer (72) associated with said housing (16) and adapted for matingly connecting the power take-off (30) to the driven implement (14); and an implement mount (42,44,46,48) adapted for supporting the driven implement (14) for movement with respect to said housing (16), characterized in that a latch (18) is pivotally mounted with respect to the main body (10) and adapted to extend around the housing (16) for securing said housing (16) with respect to the main body (10). An attachment system according to claim 1, wherein a bale handle (60) is connected to said main body (10) and adapted for gripping by the user's hand, said bale handle (60) being pivotally mounted with respect to the exterior surface of said main body. An attachment system according to claim 1 wherein the latch arrangement comprises: at least one arm (22A, 22B) adapted for pivotal movement with respect to the main body (10) about a pivot axis; a grip (24) adapted for grasping to pivot the at least one arm, the grip being fixed on the at least one arm; and a cam surface (26A, 26B) on each of the at least one arm. An attachment system according to claim 3 wherein the cam surface (26A, 26B) is adapted for biasing the housing (16) toward the main body (10). An attachment system according to claim 4 wherein the at least one arm (22A, 22B) is elastically deformed by engagement between the cam surface (26A, 26B) on each of said at least one arm and the housing (16). An attachment system according to claim 1, wherein said housing (16) includes at least one roller (28) and said latch (18) includes a cam surface (26) adapted for engaging said roller (28) to secure said housing (16) to said main body (10) and wherein at a first pivotal position of said latch (18) at least one of said latch (18) and cam surface (26) are elastically deformed a first amount, at a second pivotal position of said latch (18) at least one of said latch (18) and said cam surface (26) are elastically deformed a second amount less than said first amount, and at a third pivotal position of said latch (18) said cam surface (26) is disengaged from said roller (28), wherein said first pivotal position is operatively interposed between said second and third pivotal positions. An attachment system according to claim 6, wherein said latch (18) includes a grip (24) adapted for pivotally moving said latch (18) with respect to the main body (10) about pivot points (20a, 20B) and the grip is spaced apart from the pivot points (20A, 20B) a greater distance than the cam surfaces (26A, 26B) are spaced apart from the pivot points. An attachment system according to claim 1, wherein said latch (18) includes a grip (24) adapted for pivotally moving said latch (18) with respect to the main body (10). An attachment system according to claim 1, wherein said latch (18) includes first and second arms (22A,22B) adapted for pivotal connection on opposite sides of the main body (10), and a grip (24) extending generally transversely with respect to said arms (22A,22B) and adapted for concurrently pivoting said first and second arms (22A,22B), each of said first and second arms (22A,22B) having a respective cam surface (26A,26B) and wherein said housing (10) includes first and second projections extending from opposite sides of said housing, and a respective roller (28) mounted on each of said first and second projections and adapted for cooperatively engaging a corresponding one of said cam surfaces (26). The attachment system according to claim 1 wherein two female members (34A, 34B) are formed in the housing (16) and each adapted to matingly receive a corresponding male member (32A, 32B) extending from the main body (10). A hand held power (1) tool comprising an attachment system according to any one of claims 1 to 10. A power tool system for trimming hedges comprising an attachment system according to claim 1 wherein the main body (10) at least partially encloses the driving source and the power tool system comprises: the housing (16) adapted for mating engagement to the main body (10), the housing including a first set of relatively reciprocating blades (50A, 50B) adapted for being operatively driven by the driving source; and a second housing adapted for mating engagement to the main body, the second housing including a second set of relatively reciprocating blades adapted for being operatively driven by the driving source; wherein the housing (16) and the second housing are interchangeably connectable with respect to the main body (10).

Inventors: DYKE COLIN, EDLEBLUTE CALVIN, LESSIG WILLIAM, MELONI ROBERT, VANTRAN JOHN, WAGSTER ROBERT, DYKE, COLIN, EDLEBLUTE, CALVIN, LESSIG, WILLIAM, MELONI, ROBERT, VANTRAN, JOHN, WAGSTER, ROBERT
Applicants: BLACK & DECKER INC, BLACK & DECKER INC.
Application year: 1999
Main classification: B27B17
IPC codes: B27B17