Vegetation cutting device |
|||||||
申请号 | EP11195359.2 | 申请日 | 2011-12-22 | 公开(公告)号 | EP2606717A1 | 公开(公告)日 | 2013-06-26 |
申请人 | Black & Decker Inc.; | 发明人 | Tate, Clare; | ||||
摘要 | A vegetation cutting device (10) comprises, a housing (12), and a motor (20) located within the housing. The motor comprises a rotating output shaft (22) for driving a pair of reciprocating blades (26,28). The vegetation cutting device also comprises a rotatable front handle (32) being rotatably mounted on the housing and is adapted to rotate with respect to the housing. The rotatable front handle comprises, a first trigger (36) wherein the motor is operable on actuation of the first trigger. A release button (40) is in mechanical cooperation with the rotatable front handle for actuating rotation of the front handle. The vegetation cutting device also comprises an interlock mechanism (62,72) mechanically coupling the release button and the first trigger wherein actuation of the release button prevents actuation of the first trigger and actuation of the first trigger prevents actuation of the release button. | ||||||
权利要求 | |||||||
说明书全文 | The present invention relates to a vegetation cutting device. In particular the present invention relates to a vegetation cutting device comprising a rotatable handle. Vegetation cutting devices such as hedge trimmers are known power operated tools for cutting hedges and other foliage and vegetation. Typically hedge trimmers are powered by petrol or electric and an engine or motor drives a blade assembly comprising a pair of reciprocating blades. Many types of vegetation cutting devices, such as hedge trimmers and chainsaws employ a rear handle which can have a trigger for operation by the user and a front handle for allowing two handed use to provide greater stability when in operation. During use the user typically grips the front handle and the rear handle of the hedge trimmer. However a user may find that he wants to cut vegetation at different heights, to cut vegetation of different shapes and to cut vegetation using different actions. For example, the user may wish to cut a vertical face of a hedge and a horizontal top of the hedge. The user may find that a hedge trimmer with front and rear handles permitting only one gripping position uncomfortable and frustrating to use. Known hedge trimmers can have a front bail handle located near the blade assembly. The bail handle typically surrounds the top and sides of the hedge trimmer. This means that the user can rotate the hedge trimmer along the longitudinal axis of the hedge trimmer and still grip the front and rear handles providing more gripping positions. However a problem occurs if a dual switching operation is desired. A dual switching mechanism can provide a switch on the rear handle and another switch on the front bail handle and the hedge trimmer will only operate if both switches are actuated. Providing a switch on the front bail handle which can be actuated in all the positions means that the switch located on front bail handle has to extend along the entire length of the bail handle. This makes the front bail handle cumbersome and can make the front switch more likely to be accidently activated. Some other hedge trimmers are known to have rotating handles to permit different gripping positions. For example, Another known hedge trimmer is shown in If the user grips the rear handle with both hands to activate the mechanisms in A hedge trimmer providing multiple gripping positions which can be easily be achieved during operation is desired. Embodiments of the present invention aim to address the aforementioned problems. According to an aspect of the present invention there is a vegetation cutting device comprising: a housing; a motor located within the housing, the motor comprising a rotating output shaft for driving one or more blades; a rotatable front handle being rotatably mounted on the housing and being adapted to rotate with respect to the housing, the rotatable front handle comprising a first trigger, wherein the motor is operable on actuation of the first trigger; a release button in mechanical cooperation with the rotatable front handle for actuating rotation of the front handle; and an interlock mechanism mechanically coupling the release button and the first trigger wherein actuation of the release button prevents actuation of the first trigger and actuation of the first trigger prevents actuation of the release button. By providing a front rotating handle the user can modify the vegetation cutting device to provide multiple gripping positions without placing the vegetation cutting device on the ground. By gripping the front handle the user can hold the vegetation cutting device more stably and also rotate the handle. In this way vegetation cutting device is evenly balanced about the front rotating handle. The interlock mechanism means that the use cannot operate the hedge vegetation cutting device and move the front rotatable handle at the same time. The interlock mechanism only allows operation of the vegetation cutting device or rotation of the front rotatable handle. This means that the vegetation cutting device has to be stopped before a user moves the position of the front rotatable handle. This makes modifying the gripping positions of the vegetation cutting device safer for the user. According to some embodiments the interlock mechanism may comprise a first interlock element mechanically coupled to the first trigger and a second interlock element mechanically coupled to the release button, the first and second interlock elements selectively prevent actuation of the first trigger or the release button. Preferably the first interlock element may be moveable between an unblocking position, whereby the second interlock element is moveable and a blocking position whereby the second interlock element is prevented from movement. Additionally or alternatively the second interlock element may be moveable between and unblocking position whereby the first interlock element is moveable and a blocking position whereby the first interlock element is prevented from movement. Preferably the first interlock element may comprise a moveable rib and the second interlock element comprises a moveable shoulder portion. Preferably the moveable rib may be mounted on an actuation rod mechanically connected to the first trigger and the release button comprises the moveable shoulder portion. According to some embodiments there may be a rear handle mounted on the housing and the rear handle comprises a second trigger wherein the motor is operable on actuation of the first and the second triggers. This means that the user must be holding both the front and rear handles before the vegetation cutting device will work. In this way, the vegetation cutting device demands two handed operation when activated and operation of the vegetation cutting device is safer. According to one embodiment the first and second interlock elements may be biased towards the unblocking positions. This means that when the vegetation cutting device is not in use, either operation of the vegetation cutting device or rotation of the front handle can be achieved without first moving another part of the interlock mechanism. When the shoulder portion of the release button is in the unblocking position, the release button is in a position whereby the rotatable handle is fixed with respect to the housing. When the rib of the front trigger is in the unblocking position, the front trigger is in a position whereby the motor is not in operation. Preferably the first trigger and the release button may be both depressible and depressing the first trigger prevents depressing the release button and depressing the release button prevents depressing the first trigger. A depressible release button and a depressible front trigger ensures that the user can easily select either the front trigger or the release button. At the same time this means that the interlock mechanism can be housed within the rotatable front housing. This makes the rotatable front handle compact and reduces the size of the rotatable front handle. According to some embodiments the axis of rotation of the rotatable front handle may be substantially in line with a longitudinal axis of the reciprocating blades. This means that the user will grip the vegetation cutting device in a line which is substantially parallel to the axis of the reciprocating blades. In this way the user grips the handle such that the gripping position on the front handle is offset from the axis of the reciprocating blades in substantially one direction, which reduces the turning moment the user experiences when holding the rotatable front handle. In some embodiments the rotatable front handle may be moveable between a plurality of positions. This provides greater gripping options for the user. Additionally the rotatable front handle may be rotatably mounted on a flange of the housing and the flange comprises a plurality of notches defining the plurality of positions and the release button comprises a finger portion for locating in any one of the notches. Additionally the finger portion of the release button may be moveable between a first position in which the rotatable front handle is moveable and a second position in which the finger is located in one of the notches thereby preventing rotation of the front rotatable handle. Preferably the vegetation cutting device may be a hedge trimmer. Preferably the vegetation cutting device may be a chainsaw. The one or more blades may be a pair of reciprocating blades. Alternatively the one or more blades can be a blade on a chain for a chainsaw. Various other aspects and further embodiments are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which:
The hedge trimmer 10 comprises a housing 12 formed from a clam shell construction comprising a first half 14 and a second half 16. The internal components of the hedge trimmer 10 will now be explained referring to The motor 20 comprises an armature having a rotary drive shaft 22. The rotary draft shaft 22 is coupled to a blade assembly 24 via gearing which drives a pair of reciprocating blades 26 and 28. The reciprocating blades 26, 28 are moveable in opposite directions along substantially linear paths. In some alternative embodiments, the hedge trimmer 10 can be petrol or gas powered and the rotary drive shaft is driven by an internal combustion engine. The exterior of the hedge trimmer 10 will now further be discussed with reference to It will be clear that the hedge trimmer 10 can be used in a variety of different orientations however the hedge trimmer 10 has an overall directionality. The user will always hold the hedge trimmer 10 with the blade assembly 24 facing away from their body. The "front" of the hedge trimmer is understood to be towards the blade assembly 24 end and the "rear" of the hedge trimmer is understood to be towards the adaptor 18 end. In this way the rotatable front handle 32 is the handle which is closest to the blade assembly 24 and the rear handle 30 is the handle which is further from the blade assembly 24 and closest to the user's body. The hedge trimmer 10 is activated by the user depressing a first actuation means or front trigger 36 located on the rotatable front handle 32. Depressing the front trigger 36 mechanically actuates a switch which completes an electrical circuit and operates the motor 20. In some embodiments the front trigger 36 is a button which extends along a forward facing of the front rotatable handle 32. The front trigger 36 has a biasing member, such as a spring, to bias the front trigger 36 to an "off" position. Additionally or alternatively the hedge trimmer 10 has a dual switching mechanism. The dual switching mechanism comprises the front trigger 36 and a second actuation means or a rear trigger 38. The motor 20 is operable only on actuation of both the first and rear trigger 36, 38. This means that the user has to be holding the hedge trimmer 10 with both hands to operate the hedge trimmer 10. The rear trigger 38 is a depressible trigger button and has a biasing member such as a spring to bias the rear trigger 38 to an "off" position. The rotatable front handle 32 as shown in The release button 40 is a depressible button and has a biasing member, such as a spring, to bias the release button 40 to a position which fixes the rotatable front handle 32 in place. This means that when the user is not using the hedge trimmer 10 the hedge trimmer 10 defaults to a state whereby the hedge trimmer 10 is not activated and the rotatable front handle 32 is fixed in position. The front trigger 40 and dual switching mechanism will now be described in further detail with reference to The housing 12 has a flange 52 and the rotatable front handle 32 is rotatably mounted thereon. The housing 12 has a neck portion 51 narrower and rearwards of the flange 52 and a cuff portion 54 of the rotatable front handle 32 co-operates with the neck portion 51. The rotatable front handle 32 has a front trigger 36 which is mechanically coupled to a switching unit 44 via a mechanical linkage. The switching unit 44 has a microswitch 45. The mechanical linkage comprises a first rod 42 which is connected at one end to the front trigger 36. In other embodiments the front trigger 36 can be integral with the first rod 42. The other end of the first rod 42 has a circular plate 46 which abuts against another circular plate 48 of a second rod 50. This means that the rotatable front handle 32 can rotate and the front trigger 36 can still move the second rod 50 via the first rod 42 in any position. The movement of the rotatable front handle 32 will now be discussed in further detail with reference to The release button 40 is shown in greater detail in When the release button 40 is in the second position, as shown in In some embodiments the front rotatable handle can be rotated to a plurality of positions. Indeed there can be five positions including one central position, as shown in The interlock mechanism will now be described in further detail with reference to The shoulder portion 62 of the release button 40 is moveable along a path which intersects a path of the rib 72 of the first rod 42. When the release button 40 is in the first position which prevents rotation of the rotatable front handle 32, the shoulder portion 62 is retracted so that the end 76 of the shoulder portion 62 is in line with wall 74. This means that the shoulder portion 62 is in an unblocking position and the shoulder portion 62 does not impede the movement of the rib 72. When the front trigger 36 is actuated, the first rod 42 moves rearwards and the rib 72 moves to a blocking position. Indeed, the rib 72 moves to a position whereby the rib 72 is adjacent to the end 76 of the shoulder portion 62. When the rib 72 is adjacent to the end 76 of the shoulder portion 62, the shoulder portion 62 cannot move past the rib 72. This means that the release button 40 is inoperable when the front trigger is actuated 36. In this way the interlock mechanism provides a mechanical "OR" gate whereby only the front trigger or the release button can be operated. In some embodiments the interlock mechanism can be any means suitable for ensuring the only the front trigger or the release button can be operated. This means that the hedge trimmer 10 has to be stopped before a user moves the position of the front rotatable handle 32. This makes modifying the gripping positions of the vegetation cutting device safer for the user. Indeed, other mechanical arrangements can be provided other than the shoulder and rib arrangement. For example Embodiments of the present invention have been discussed with particular reference to the examples illustrated. However it will be appreciated that variations and modifications may be made to the examples described within the scope of the invention. |