GB2495758A - Vibration dampened side handle for power tool - Google Patents

Abstract

A side handle, particularly for a power tool, has a central bar 1012 and a tubular grip 1016 mounted on and surrounding central bar 1012. The handle also comprises a vibration dampener 1000 having a preferably hexagonal central plate 1004 fixedly mounted on central bar 1012 and a plurality of resiliently deformable arms 1002, preferably six, attached to or integral with the plate 1004 and extending from plate 1004 towards an inner wall of grip 1016. An ends of each arm 1002 is in resilient frictional contact with the inner wall 1020 of grip 1016. Preferably arms 1002 and plate 1004 are metal. Plate 1004 is preferably perpendicular to a longitudinal axis of bar 1012, and arms 1002 are preferably located symmetrically about the bar at corners of plate 1004. The handle preferably comprises a cap 1014 for transferring rotation between bar 1012 and grip 1016.

Description

SIDE HANDLE

The present invention relates to a side handle for a power tool, and in particular, to a side handle for a drill.

Drills, in particular, hammer drills, comprise a main housing in which is mounted a spindle and a motor, which rotatingly and/or axially drives the spindle via gears and/or a hammering mechanism, also located within the housing. The spindle transfers the rotational and/or axial movement of the spindle to a cutting tool, such as a drill bit, via a chuck or tool holder attached to the end of the spindle, forward of the main housing. Typically, such drills have two handles, a rear handle attached at the rear of the main housing and a side handle attached towards the front of the main housing, on one side of the main housing. Often, the side handle can be attached to either side of the main housing.

One type of side handle comprises a hand grip which is attached at one end to a base, which is attached to the side of main housing, and which extends away from the base and the housing in a direction generally perpendicular to the longitudinal axis of the spindle of the drill.

A problem with power tools, in particular drills, is that they generate a large amount of vibration during their operation. The transfer of the vibration from the tools to the hands of the operator can lead to injury to the hands of the operator and therefore it is desirable to minimise the amount of vibration transferred. One way of achieving this to provide a vibration dampener between the hand grip and the base to reduce the amount of vibration transferred from the base to the hand grip.

EP2082846, as published, describes such a design of side handle for a drill in paragraphs 45 to 52 with reference to Figures 7 to 13. The side handle comprises a hand grip 84 (using the same reference numbers as EP2082846) which is attached to a bolt 106 via two vibration dampeners 118, 120. The bolt 106 attaches to a base 80. The dampeners 118, 120 are made from resilient rubber. During use of such a side handle, the operator applies pressure to the hand grip 84 in a direction generally parallel to the longitudinal axis of the spindle of the drill to which the handle is attached, which is perpendicular to longitudinal axis of the hand grip. As such, this applies a rotation force onto the hand grip 84 in a direction perpendicular to the longitudinal an axis of the hand grip about an axis of rotation located in close proximity to the base 80. This results in a large degree of sideways pressure being placed on the dampener 118 closest to the base 80, which, due to it being made from rubber, becomes compressed on one side. This reduces the performance of the vibration dampener 118.

The present invention overcomes or at least reduces the problems associated the design of side handle disclosed in EP2082846.

Accordingly, there is provided a side handle for a power tool comprising: a central bar; a tubular grip which is mounted on and surrounds the central bar via a vibration dampener; the vibration dampener comprising a spling having a central plate, which is mounted in a non rnoveable manner on the central bar, and a plurality of resiliently deformable arms attached to the plate and which extend away from the plate towards an inner wall of the grip, the ends of each of the arms being in resilient frictional contact with the inner wall of the grip.

An embodiment of the present invention will now be described with reference to the accompanying drawings of which: Figure 1 shows an exploded side view of a the side handle according to the present invention; Figure 2 shows a perspective end view of the side handle (excluding the base); Figure 3 shows a perspective end view of the side handle with the plastic cap in an exploded position; Figure 4 shows a perspective end view of the side handle with the spring and plastic cap in an exploded position; Figure 5 shows a cut away rear perspective view; Figure 6 shows a vertical cross sectional view; and Figure 7 shows the two component parts of the plastic cap.

An embodiment of a side handle according to the present invention will now be described. The embodiment is for a side handle for a drill.

Referring to figure 1, the side handle comprises a plastic grip 1016 which is mounted on a bolt 1012 via a vibration dampening mechanism (as shown in FigureS and which is described in more detail below). The bolt 1012 has a threaded end 1019 which projects from the end of the grip 1016. The side handle comprises a base 1050 and an attachment oop 1052. The attachment loop 1052 comprises a flexible metal strip 1054 which is attached at both ends to a nut 1056 which has a threaded passage 1058 formed through it. The base 1050 has a curved support 1060 and a tubular passageway 1062 which passes through its length. In use, the metal strip 1054 is wrapped around the body of a drill (not shown). The nut 1056 is inserted into the tubular passage 1062 from the side of the base 1050 containing the curved support 1060. The threaded end 1019 of the bolt 1012 is inserted into the other end of the tubular passage 1062 until it engages with the threaded passage 1058 of the nut 1056. The bolt 1012 is then rotated using the hand grip 1016, causing the threaded end 1019 of the bolt 1012 to screw into the threaded passage 1058 of the nut 1056. As the threaded end 1019 of the bolt 1012 screws into the threaded passage 1058 of the nut 1056, the nut 1056 is drawn towards the grip 1016. This causes the nut 1056 and metal strip 1054 to be drawn into the tubular passage 1062, resulting in it tightening around the body of the drill. Once the metal strip 1054 is wrapped tightly around the body of the drill, the grip 1016 is prevented from further rotation. At this point the curved support 1060 also abuts the side of the drill. The side handle is thereby secured to the drill. In order to release the side handle, the grip 1016 is rotated in the opposite direction, thereby unscrewing the threaded end 1019 of the bolt 1012 from the nut 1056. The entrance 1064 of the tubular passage 1062 is tapered to facilitate the entry and exit of the nut 1056 and metal strip 1054 into the tubular passage 1062.

The vibration dampening mechanism will now be described with reference to Figures 2 to 6. The vibration dampening mechanism comprises a metal spring 1000.

The metal spring 1000 comprises six arms 1002 which are resiliently deformable and which are integrally formed with and extend from a central hexagonal plate 1004 in a symmetrical shape. Each arm 1002 is L shaped with the first part 1080 extending away from the plate 1004 in the plane of the plate 1004. The second part 1082 extends at an angle to the first part. A circular aperture 1006 is formed through the plate 1004. Formed on the bolt 1012 is a flange 1008 having two flat sides 1010 which extend tangentially to the longitudinal axis 1066 of the bolt 1012. The spring 1000 is located on the circular shank of the bolt 1012 immediately behind the flange 1008 as best seen in Figures 3 and 6. The ends of the arms 1002 have resilient frictional contact with the inner wall 1020 of the grip 1016 with a predetermine pre-force due to arms 1002 being bent inwardly away from their non deformed positions by the inner wall 1020 of the grip 1016. This locates the bolt 1012 centrally within the plastic grip 1016 in the middle of the grip 1016. The advantage of using a metal spring 100 instead of rubber for the damping element as described in EP2082846 is the improved damping qualities. When vibrations are of a high frequency and the grip moves at high speed relative to the bolt 1012, unlike metal springs, rubber dampeners loose some of their damping properties.

The plastic cap 1014 comprises two components as best seen in Figure 7.

The plastic cap comprises a cover 2000 and a circular insert 2002. The cover 2000 comprises a recess 1068 which corresponds to the shape of the flange 1008 on the bolt 1012. The recess 1068 comprises two flat sides 2004. A circular aperture 1017 is formed through the base of the recess 1068. Two slots 2006 are formed lengthwise in the sides of the cover 2000 on opposite sides of the cover.

The circular insert 2002 comprises a circular ring 2008 having a first pair of clips 1015 located on one side of the ring 2006 diametrical opposed to each other extending in a first direction, and a second pair of clips 2010 located on the other side of the ring 2008 to the first pair 1015, diametrical opposed to each other and extending in a second direction which is directly opposite to that of the first pair 1015.

As such the first pair of clips 1015 extend parallel to but in the opposite direction to second pair 2010. The first pair of clips 1015 are arranged around the circumference of the ring 2008 at 90 degrees relative to the second pair of clips 2010.

When the two components of the plastic cap 2014 are assembled, the ring 2008 is located adjacent cover 2000 so that it surrounds the recess 1068 with each of the second pair of clips 2010 locating within one of the slots 2006. The width of each of the second pair of clips 2010 is slight smaller than the width of the slot 2006 in which it is located so that there is a limited amount of rotational movement allowed between the cover and the ring 2002.

The assembled plastic cap is mounted on the shank of the bolt in front of the flange 1008, the flange 1008 locating in the recess 1068 of the cover 2000 with the front end 1019 of shank passing through the aperture 1017, the flats of the flange 1008 engaging with the flat sides 2004 of the recess 1068 to prevent rotational movement between the cover 2000 and the bolt 1012.

Formed on the inner walls 1020 of the grip 1016 are ribs 1022 which are located behind the flange 1008 of the boltlOl2. The ring 2008 is located between the cover 2000 and ribs 1022. The first pair clips 1015 on the ring 2008 locate between the ribs 1022. The width of each of the first pair of clips 1015 is slightly smaller than the width of the space between the ribs 1022 in which it is located so that there is a limited amount of rotational movement allowed between the ribs and the ring 2002.

The plastic grip 1016 can move perpendicularly (Arrows C and 0) to longitudinal axis 1066 of the bolt 1012 relative to the bolt 1012 by the bending of the arms 1002 of the spring 1000 due to the flexible nature of the arms 1002. The arms 1002 absorb vibration, reducing the amount transferred from the bolt 1012 to the grip 1016. However, the resilience of the arms 1012 is sufficient to support the pressure applied to the grip 1012 by the operator during use whilst reducing vibration.

The grip 1016 can rotate (Arrow B) on the bolt 1012 over a limited range of rotational movement about the longitudinal axis 1066 of the bolt 1012 due to the limited amount of rotational movement allowed between the cover 2000 and the ring 2002 and the limited amount of rotational movement allowed between the ribs 1022 of the grip 1016 and the ring 2008.

When a users wishes to rotate the bolt 1012 via the grip 1016, the user rotates the grip 1016. Initially, the grip 1016 can freely rotate relative to the bolt 1012 until the sides of the first pair of clips 1015 on the ring 2008 engage with the sides of the ribs 1022 and the sides of the second pair of clips 2010 engage with the sides of the slots 2006 of the cover. At this point the rotational movement of the grip is transferred directly to the bolt via the plastic cap 1014. When the grip 1016 rotates relative to the bolt 1012, the resilient arms of the spring can either deform slightly due to the frictional engagement with the inner wall 1022 of the grip or slide along the inner wall of the grip 1016.

It will be appreciated that the design of the arms 1002 can arranged to alter the amount of resilience in the directions of Arrows C and 0, or even prevent movement in any one of those directions. The use of L shaped arms is particular beneficial in providing sufficient resilience in the direction of Arrow C so that, when the operator applies pressure to the hand grip 1016 in a direction generally parallel to the longitudinal axis of a spindle of the drill to which the handle is attached, which is perpendicular to longitudinal axis of the grip 1016, the arms 1002 provide sufficient support to the grip 1016 whilst providing good vibration dampening to the grip 1016.

Located at the far end of the bolt 1012 remote from the flange 1008, is a second vibration dampener 1070. The dampener 1070 has the same design as the second dampener 120 (using the same reference numbers as EP2082846) described in EP2082846.

Claims (1)

1. <claim-text>CLAIMS1. A side handle for a power tool comprising: a central bar 1012; a tubular grip 1016 which is mounted on and surrounds the central bar 1012 via a vibration dampener; the vibration dampener comprising a spring 1000 having a central plate 1004, which is mounted in a non moveable manner on the central bar 1012, and a plurality of resiliently deformable arms 1002 attached to the plate 1004 and which extend away from the plate 1004 towards an inner wall of the grip 1016, the ends of each of the arms being in resilient frictional contact with the inner wall 1020 of the grip 1016.</claim-text> <claim-text>2. A side handle as claimed in claim 1 wherein the plane of the plate 1004 is perpendicular to a longitudinal axis 1066 of the bar 1012.</claim-text> <claim-text>3. A side handle as claimed in either of claims 1 or 2 wherein the arms 1002 are located symmetrically around the bar 1012.</claim-text> <claim-text>4. A side handle as claimed in any one of claims 1 to 3 wherein there are six arms 1002.</claim-text> <claim-text>5. A side handle as claimed in claims 4 wherein the periphery of the plate 1004 is hexagonal in shape, each of the arms 1002 being attached to a corner of the plate 1004.</claim-text> <claim-text>6. A side handle as claimed in any of claims ito 5 wherein the arms 1002 are made from metal.</claim-text> <claim-text>7. A side handle as claimed in any of claims 1 to 6 wherein the plate 1004 is made from metal.</claim-text> <claim-text>8. A side handle as claimed in any of claims ito 7 wherein the arms 1002 and plate 1004 are formed integrally.</claim-text> <claim-text>9. A side handle as claimed in any of claims 1 to 8 wherein there is further provided a cap 1014 mounted on the bar and which is connected between the grip and the bar 1012 and which is capable of transferring rotational movement between the grip and the bar.</claim-text> <claim-text>10. A side handle as claimed in claim 9 wherein the cap comprises two parts connected to each other, a first part comprising a cover, a second part comprising a circular insert, wherein one part is connected to the grip and the other is connected to the bar.</claim-text> <claim-text>11. A side handle as claimed in claim 10 wherein there is limited rotation movement between the cover and the circular insert.</claim-text> <claim-text>12. A side handle as claimed in claim 11 wherein the circular insert comprises at least one clip 1015, each clip engaging in a corresponding slot formed in the cover, the width of the at least one clip being smaller than the width of the slot.</claim-text> <claim-text>13. A side handle as claimed in any of claims 10 to 12 wherein there is limited rotation movement between the part of the cap which connects to the grip and the grip.</claim-text> <claim-text>14. A side handle as claimed in any of claims 10 to 13 wherein the circular insert is connected to the grip and the cover is connected to the bar, wherein the circular insert comprises at least one clip which engages with the grip.</claim-text> <claim-text>15. A side handle as claimed in claim 14 wherein the grip comprises at least one rib, the at least one clip engaging the at least one rib.</claim-text> <claim-text>16. A side handle as claimed in any of claims 10 to 15 wherein the circular insert is connected to the grip and the cover is connected to the bar, wherein the bar further comprises a flange 1008, which locates within a recess 1068 formed within the cover 1014, the shape of the of the flange corresponding to the shape of the recess, the shape being non circular to prevent any rotational movement of cover around the bar 1012.</claim-text> <claim-text>17. A side handle as claimed in any of claims 10 to 16 wherein the grip comprises at least one rib located on a first side of the flange, wherein the plate 1004 is also mounted on the bar 1012 on the first side of the flange 1008 adjacent the flange 1008 between the flange and the at least one rib, the circular insert being mounted on the bar 1012 on the other second side of the flange 1008 adjacent the flange 1008, the at least one clip of the circular insert extends through the resilient arms of the spring into a space formed adjacent the at least one rib.</claim-text>