Power tool
A power sander (2) has a housing (4) supporting a mounting platen (6) for supporting a sanding head for oscillatory orbital motion of the platen (6) and sanding head relative to the housing. The housing has side surfaces, a curved front surface (14) containing an on/off switch (16) for switching electrical power to a motor in the housing, a curved upper surface (20) and a generally saddle shaped graspable surface (22) located between the front surface and upper surface. The graspable surface has a concave upper portion (24) and concave side portions (26) arranged on opposite sides of the upper portion. For ergonomic handling of the sander by a user, the saddle shaped graspable surface has a concaved upper portion and side portions.
The present invention relates to power tools, and relates particularly, but not exclusively, to power sanders.
BACKGROUND OF THE INVENTIONKnown power tools, such as power drills in which a drill bit is rotated by an output shaft which is in turn rotated by means of an electric motor, generate significant amounts of vibration, which can under certain circumstances limit the length of time during which the tool can be used continuously. In addition, the housing of such tools is generally made from a durable plastics material on which it can be difficult for a user of the tool to maintain a grip when the tool is in use for a sustained period. This generally limits the degree of comfort and ease with which a user can handle the tool.
Preferred embodiments of the present invention seek to provide a power tool which is easier and more comfortable to use.
BRIEF SUMMARY OF THE INVENTIONAccording to the present invention, there is provided a power tool comprising:- a housing defining at least one handle portion having a graspable surface having first and second concave portions and a third concave portion between said first and second concave portions; and
a motor located in the housing for actuating a working member of the tool.
By providing a housing defining at least one handle portion having a graspable surface having first and second concave portions and a third concave portion between said first and second concave portions, this provides the advantage of making the power tool easier and more comfortable for the user.
The power tool may further comprise a platen mounted to said housing on a side thereof remote from at least one said handle portion.
The platen may include a narrower portion at a forward end thereof.
In the case where the power tool is a sander, this provides the advantage of enabling more accurate sanding operations to be carried out.
The platen may taper inwardly in a longitudinal direction of the tool.
The graspable surface may be generally saddle shaped.
A majority of the housing as measured in a longitudinal direction may be disposed in use over the platen.
Approximately two thirds of said housing as measured in said longitudinal direction may be disposed in use over said platen.
Substantially all of said housing as measured in a direction transverse to said longitudinal direction may be disposed in use over said platen.
The housing may further define a curved forward surface, and the tool may further comprise a motor on/off switch disposed on said curved forward surface.
At least one said first and/or said second concave portion may have a radius of curvature of 5 mm to 40 mm.
At least one said first and/or said second concave portion may have a radius of curvature of 5 mm to 15 mm.
At least one said first and/or said second concave portion may have a radius of curvature of 8 mm to 12 mm.
Said third concave portion may have a radius of curvature of 5 mm to 40 mm.
Said third concave portion may have a radius of curvature of 15 mm to 30 mm.
Said third concave portion may have a radius of curvature of 20 mm to 25 mm.
The tool may be a power sander.
According to another aspect of the present invention, there is provided a power tool comprising:
a housing defining a forward surface and an upper surface, and a notch defined in said upper surface rearwardly of said forward surface;
a platen moveably mounted to said housing; and
a motor located in the housing for causing oscillatory movement of the platen relative to the housing;
wherein a majority of the housing as measured in a longitudinal direction of the tool and a direction transverse to said longitudinal direction is disposed over said platen in use.
The upper surface may be curved downwardly in a rearward direction from an upper edge of said forward surface to define a recessed surface area and then curved upwardly rearwardly from said recessed surface area to define said notch.
The forward surface may be curved.
Substantially all of said portion of said housing disposed over said platen in use as measured in the longitudinal direction may be also disposed over said platen in use as measured in a direction transverse thereto.
At least one said first and/or said second concave portion may have a radius of curvature of 5 mm to 40 mm.
At least one said first and/or said second concave portion may have a radius of curvature of 5 mm to 15 mm.
At least one said first and/or said second concave portion may have a radius of curvature of 8 mm to 12 mm.
Said third concave portion may have a radius of curvature of 5 mm to 40 mm.
Said third concave portion may have a radius of curvature of 15 mm to 30 mm.
Said third concave portion may have a radius of curvature of 20 mm to 25 mm.
The tool may be a power sander.
According to a further aspect of the present invention, there is provided a power tool comprising:-
a housing having side surfaces below an upper surface to form a graspable handle portion;
a platen mounted to said housing, wherein a majority of said housing as measured in a longitudinal direction of the tool and in a direction transverse to said longitudinal direction is disposed over said platen in use;
a motor located in the housing for causing oscillatory movement of said platen relative to the housing; and
at least one chamber containing at least one gel material protruding from each said side surface.
The tool may further comprise a third chamber containing a gel material disposed on said upper surface.
BRIEF DESCRIPTION OF THE DRAWINGSPreferred embodiments of the invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:-
Referring to FIGS. 1 to 9, a power sander 2 has a housing 4 supporting a mounting platen 6 for supporting a sanding head 8 (
For ergonomic handling of the sander by a user, the saddle shaped graspable surface 22 has a concaved upper portion 24 having a radius of curvature of about 23 mm, and side portions having radii of curvature of about 10 mm.
The upper surface 20 of the housing 4 is defined by a blister pack 30, defining a gel-containing chamber 32 containing vibration absorbing gel formed from a semi solid silicone rubber or polyurethane material and protruding from an aperture in a clamping plate 34. Similarly, each side surface 10, 12 is defined by a blister pack 36, defining a gel-containing chamber 38 protruding through an aperture in clamping plate 40. It can therefore be seen that the external surface of the sander 2 to be gripped by a user is defined by the gel-containing chambers 32, 38 of blister packs 30, 36 respectively, and the clamping plates 34, 40, so that the amount of vibration transmitted to a user's hand is reduced by means of the gel material contained in the blister packs 30, 36.
As shown in greater detail in
The pins 43 on clamping plate 40 are of such length that when the blister pack 36 is located on the pins and the clamping plate 40 is mounted to the housing 4 by locating the pins in apertures 42 on the housing 4, the pins protrude from the inner wall of the housing 4 to a depth of approximately 3 mm. The clamping plate 40 is then sealed to the housing 4 by a technique known to persons skilled in the art as “hot staking” in which a heated mandrel is applied to the protruding ends of the pins, which melts the protruding ends so that they are widened in a generally circular arrangement and fix the pins to the housing 4 in a manner similar to that of a rivet. Alternatively, the distal ends of the pins can be heated by means of ultrasound. The clamping plate 40 is then sealed to the housing and prevents removal of the clamping plate 40 from the housing 4, and the gel-containing chamber 38 of blister pack 36 protrudes through the aperture 45 of clamping plate 40 to define part of side surface 10, while removal of the blister pack 36 is prevented because the pins pass through the apertures 44 in the blister pack 36.
Similarly, the blister pack 36 forming part of opposite side surface 12 and the blister pack 30 forming part of upper surface 20 are secured to the housing in a similar manner by means of heat or ultrasound.
The mounting platen 6 surrounds the second drive shaft 62, and is spaced radially therefrom. This means that the mounting platen 6 itself is not directly driven by either of the drive shafts.
In
A brake pad 76 is provided on the under-surface of the mounting platen 6. The brake pad 76 comprises a resilient member 78 in the form of a ring formed from a synthetic rubber resilient material, and an abrasion resistant contact layer 80 comprising polytetrafluoroethylene (PTFE) filed with carbon fibre or glass for increased abrasion resistance. The arrangement of the layers is such that when the sanding platen 8 is secured in place onto the drive 62 then the resilient ring 78 is under compression so that a resultant load is put by the filled PTFE layer 80 onto a reaction surface part 82 of the underlying upper surface of the sanding platen 8. The purpose of this brake 76 is two-fold: first, in use, the brake acts as a speed limiter, operating in particular to prevent scratches when the unit is placed on and taken off the work surface, and secondly when the unit is switched off, the stop time is very much reduced compared to a non-braked tool. In operation the drive shaft 50 is typically driven at a rotational speed of 12000 rpm, which is too fast a speed for rotation of the sanding platen 8. The brake pad 76 limits the rotational speed of the platen to an acceptable operating speed, typically around 1200 rpm, or 10% of the rotational speed of the motor.
In line with the upwardly directed projections 88, and projecting in the other direction, from the opposite surface of the mounting platen 6 are four hollow, generally cylindrical pin shaped coupling members 96. The pin-shaped coupling members 96 are also integrally formed with the mounting platen 8. The substantially flat mounting platen with its projecting portions 88 and 96 are preferably integrally injection moulded from polymeric material or diecast zinc.
The four coupling pins 96, provided on the opposite surface of the mounting platen 6 from the flexible legs 64, in corresponding positions, i.e. vertically aligned with the legs 64 as shown in
Each coupling pin 96 is an integrally formed part shaped as a hollow cylinder. The pin member 96 contains a radially directed flange 98 extending partially into the hollow of the pin member 96, to act as a stop member for a separate externally screw threaded headed bolt member 100 (see
As best seen in
As shown in
By means of the co-operating coupling means 96 and 92, the sanding shoe 84 and mounting platen 6 are therefore securely located substantially to prevent relative movement between the mounting platen 6 and the sanding shoe 84 in a plane perpendicular to the axis of the bearing 60. Relative movement parallel to the axis of the bearing 60 is, of course, prevented by the nut 70 and washer 72 attachment.
In operation, when the motor is switched on and the drive shafts 50 and 62 turn, since the sanding shoe 84 is prevented from rotation relative to the mounting platen 6, and the mounting platen 6 is fixed relative to the housing 4 by means of legs 64, then free rotation of the sanding shoe 84 around the bearing 60 axis is prevented. The flexibility in the legs 64, however, allows the sanding platen 84 to follow the rotating motion of the eccentric spindle itself driven by the first drive shaft 50. Therefore the sanding shoe 84 is allowed to oscillate within a fixed orbit due to the flexibility of the legs 64.
In order to ensure that the sanding shoe 84 is always located the correct way round on the mounting platen 6, the coupling means 96 and 92 are non uniformly spaced over the surface of the mounting platen 6 and the sanding platen 84, those on one lateral side of the platens (the right as shown in
It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.
Claims
1. A power tool comprising:-
- a housing defining at least one handle portion having a graspable surface having first and second concave portions and a third concave portion between said first and second concave portions; and
- a motor located in the housing for actuating a working member of the tool.
2. A power tool according to claim 1, wherein the graspable surface is generally saddle shaped.
3. A power tool according to claim 1, further comprising a platen mounted to said housing on a side thereof remote from at least one said handle portion.
4. A power tool according to claim 3, wherein the platen includes a narrower portion at a forward end thereof.
5. A power tool according to claim 3, wherein the platen tapers inwardly in a longitudinal direction of the tool.
6. A power tool according to claim 3, wherein a majority of the housing as measured in a longitudinal direction is disposed in use over the platen.
7. A power tool according to claim 6, wherein approximately two thirds of said housing as measured in said longitudinal direction is disposed in use over said platen.
8. A power tool according to claim 3, wherein substantially all of said housing as measured in a direction transverse to said longitudinal direction is disposed in use over said platen.
9. A power tool according to claim 8, wherein the housing further defines a curved forward surface, and the tool further comprises a motor on/off switch disposed on said curved forward surface.
10. A power tool according to claim 9, wherein at least one said first and/or said second concave portion has a radius of curvature of 5 mm to 40 mm.
11. A power tool according to claim 10, wherein at least one said first and/or said second concave portion has a radius of curvature of 5 mm to 15 mm.
12. A power tool according to claim 11, wherein at least one said first and/or said second concave portion has a radius of curvature of 8 mm to 12 mm.
13. A power tool according to claim 12, wherein said third concave portion has a radius of curvature of 5 mm to 40 mm.
14. A power tool according to claim 13, wherein said third concave portion has a radius of curvature of 15 mm to 30 mm.
15. A power tool according to claim 14, wherein said third concave portion has a radius of curvature of 20 mm to 25 mm.
16. A power tool according to claim 15, wherein the tool is a power sander.
17. A power tool comprising:-
- a housing defining a forward surface and an upper surface, and a notch defined in said upper surface rearwardly of said forward surface;
- a platen moveably mounted to said housing; and
- a motor located in the housing for causing oscillatory movement of the platen relative to the housing;
- wherein a majority of the housing as measured in a longitudinal direction of the tool and a direction transverse to said longitudinal direction is disposed over said platen in use.
18. A power tool according to claim 17, wherein the upper surface is curved downwardly in a rearward direction from an upper edge of said forward surface to define a recessed surface area and then curved upwardly rearwardly from said recessed surface area to define said notch.
19. A power tool according to claim 17, wherein the forward surface is curved.
20. A power tool according to claim 17, wherein substantially all of said portion of said housing disposed over said platen in use as measured in the longitudinal direction is also disposed over said platen in use as measured in a direction transverse thereto.
21. A power tool according to claim 17, wherein at least one said first and/or said second concave portion has a radius of curvature of 5 mm to 40 mm.
22. A power tool according to claim 21, wherein at least one said first and/or said second concave portion has a radius of curvature of 5 mm to 15 mm.
23. A power tool according to claim 22, wherein at least one said first and/or said second concave portion has a radius of curvature of 8 mm to 12 mm.
24. A power tool according to claim 17, wherein said third concave portion has a radius of curvature of 5 mm to 40 mm.
25. A power tool according to claim 24, wherein said third concave portion has a radius of curvature of 15 mm to 30 mm.
26. A power tool according to claim 25, wherein said third concave portion has a radius of curvature of 20 mm to 25 mm.
27. A power tool according to claim 17, wherein the tool is a power sander.
28. A power tool comprising:-
- a housing having side surfaces below an upper surface to form a graspable handle portion;
- a platen mounted to said housing, wherein a majority of said housing as measured in a longitudinal direction of the tool and in a direction transverse to said longitudinal direction is disposed over said platen in use;
- a motor located in the housing for causing oscillatory movement of said platen relative to the housing; and
- at least one chamber containing at least one gel material protruding from each said side surface.
29. A power tool according to claim 28, further comprising a third chamber containing a gel material disposed on said upper surface.
Type: Application
Filed: Dec 22, 2004
Publication Date: Jan 5, 2006
Inventor: Nigel Robson (Lowfell)
Application Number: 11/019,840
International Classification: B24B 27/08 (20060101);