U.S. patent application number 11/019840 was filed with the patent office on 2006-01-05 for power tool.
Invention is credited to Nigel Robson.
Application Number | 20060003680 11/019840 |
Document ID | / |
Family ID | 34930461 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060003680 |
Kind Code |
A1 |
Robson; Nigel |
January 5, 2006 |
Power tool
Abstract
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.
Inventors: |
Robson; Nigel; (Lowfell,
GB) |
Correspondence
Address: |
John Yun;Black & Decker Corporation
Mail Stop TW199
701 E. Joppa Rd
Towson
MD
21286
US
|
Family ID: |
34930461 |
Appl. No.: |
11/019840 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
451/357 |
Current CPC
Class: |
B25F 5/02 20130101 |
Class at
Publication: |
451/357 |
International
Class: |
B24B 27/08 20060101
B24B027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2004 |
EP |
EP 04254013.8 |
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.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to power tools, and relates
particularly, but not exclusively, to power sanders.
BACKGROUND OF THE INVENTION
[0002] Known 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.
[0003] Preferred embodiments of the present invention seek to
provide a power tool which is easier and more comfortable to
use.
BRIEF SUMMARY OF THE INVENTION
[0004] According 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
[0005] a motor located in the housing for actuating a working
member of the tool.
[0006] 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.
[0007] The power tool may further comprise a platen mounted to said
housing on a side thereof remote from at least one said handle
portion.
[0008] The platen may include a narrower portion at a forward end
thereof.
[0009] In the case where the power tool is a sander, this provides
the advantage of enabling more accurate sanding operations to be
carried out.
[0010] The platen may taper inwardly in a longitudinal direction of
the tool.
[0011] The graspable surface may be generally saddle shaped.
[0012] A majority of the housing as measured in a longitudinal
direction may be disposed in use over the platen.
[0013] Approximately two thirds of said housing as measured in said
longitudinal direction may be disposed in use over said platen.
[0014] Substantially all of said housing as measured in a direction
transverse to said longitudinal direction may be disposed in use
over said platen.
[0015] 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.
[0016] At least one said first and/or said second concave portion
may have a radius of curvature of 5 mm to 40 mm.
[0017] At least one said first and/or said second concave portion
may have a radius of curvature of 5 mm to 15 mm.
[0018] At least one said first and/or said second concave portion
may have a radius of curvature of 8 mm to 12 mm.
[0019] Said third concave portion may have a radius of curvature of
5 mm to 40 mm.
[0020] Said third concave portion may have a radius of curvature of
15 mm to 30 mm.
[0021] Said third concave portion may have a radius of curvature of
20 mm to 25 mm.
[0022] The tool may be a power sander.
[0023] According to another aspect of the present invention, there
is provided a power tool comprising:
[0024] a housing defining a forward surface and an upper surface,
and a notch defined in said upper surface rearwardly of said
forward surface;
[0025] a platen moveably mounted to said housing; and
[0026] a motor located in the housing for causing oscillatory
movement of the platen relative to the housing;
[0027] 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.
[0028] 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.
[0029] The forward surface may be curved.
[0030] 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.
[0031] At least one said first and/or said second concave portion
may have a radius of curvature of 5 mm to 40 mm.
[0032] At least one said first and/or said second concave portion
may have a radius of curvature of 5 mm to 15 mm.
[0033] At least one said first and/or said second concave portion
may have a radius of curvature of 8 mm to 12 mm.
[0034] Said third concave portion may have a radius of curvature of
5 mm to 40 mm.
[0035] Said third concave portion may have a radius of curvature of
15 mm to 30 mm.
[0036] Said third concave portion may have a radius of curvature of
20 mm to 25 mm.
[0037] The tool may be a power sander.
[0038] According to a further aspect of the present invention,
there is provided a power tool comprising:-
[0039] a housing having side surfaces below an upper surface to
form a graspable handle portion;
[0040] 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;
[0041] a motor located in the housing for causing oscillatory
movement of said platen relative to the housing; and
[0042] at least one chamber containing at least one gel material
protruding from each said side surface.
[0043] The tool may further comprise a third chamber containing a
gel material disposed on said upper surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Preferred 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:-
[0045] FIG. 1 is a perspective view of a power sander embodying the
present invention;
[0046] FIG. 2 is a top view of the sander of FIG. 1;
[0047] FIG. 3 is a rear view of the sander of FIG. 1;
[0048] FIG. 4 is a front view of the sander of FIG. 1;
[0049] FIG. 5 is a left side view of the sander of FIG. 1;
[0050] FIG. 6 is a right side view of the sander of FIG. 1;
[0051] FIG. 7 is a detailed rear view of a top surface of the
sander of FIG. 1;
[0052] FIG. 8 is a detailed side view of the surface of FIG. 7;
[0053] FIG. 9A is an exploded perspective view of the housing and
gripping portion of the sander of FIG. 1 from the right side;
[0054] FIG. 9B is an exploded perspective view of the housing and
gripping portion of the sander of FIG. 1 from the left side;
[0055] FIG. 10 is a side cross sectional view of part of the sander
of FIG. 1;
[0056] FIG. 11 is a view, corresponding to FIG. 10, of a sander of
a second embodiment of the present invention;
[0057] FIG. 12 is a perspective view of a mounting platen and
sanding shoe of the sander of FIG. 10; and
[0058] FIG. 13 is a perspective view of the mounting platen and
sanding shoe of FIG. 10, showing the attachment side of the
mounting platen;
DETAILED DESCRIPTION OF THE INVENTION
[0059] 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
(FIG. 10) for oscillatory orbital motion of the platen 6 and
sanding head 8 relative to the housing 4. The housing 4 has side
surfaces 10, 12, a curved front surface 14 containing an on/off
switch 16 for switching electrical power to a motor 18 (FIG. 10) in
the housing 4, a curved upper surface 20 and a generally saddle
shaped graspable surface 22 located between the front surface 14
and upper surface 20. The graspable surface 22 has a concave upper
portion 24 and concave side portions 26, 28 arranged on opposite
sides of the upper portion 24.
[0060] 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.
[0061] 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.
[0062] As shown in greater detail in FIGS. 9A and 9B, the blister
pack 36 forming part of side surface 10 is formed from a pair of
flexible sheets 46 of polyurethane material defining gel-containing
chamber 38 and sealed together at a peripheral portion 48
surrounding the gel-containing chamber 38. The peripheral portion
contains no vibration absorbing gel material and is pierced by a
series of apertures 44 which correspond in position to apertures 42
on the part of housing 4 to which the blister pack 36 is to be
mounted, and to pins 43 moulded onto the rear surface of clamping
plate 40. The blister pack 36 is mounted to the housing 4 by
passing the pins 43 of clamping plate 40 through the corresponding
apertures 44 in the peripheral portion of blister pack 36, and then
inserting the pins 43 into the corresponding apertures 42 on the
housing 4. In particular, the blister pack 36 is located on the
pins 43 of clamping plate 40, and the pins of the clamping plate 40
are then located in the apertures 42 on the housing. The pins 43
and apertures 42, 44 are irregularly spaced, which minimises the
risk of incorrect location of the clamping plate 40, blister pack
36 and housing 4 relative to each other.
[0063] 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.
[0064] 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.
[0065] FIG. 10 shows a drive unit including the electric motor 18
and first drive shaft 50. A fan 52 mounted on shaft 50 is arranged
to draw air in from mouth 54 of the drive unit as shown by arrow A
(FIG. 11), and direct it through extractor duct 56 to outlet 58, as
shown by arrow B. Bearing 60 is eccentrically located radially in
respect to shaft 50, and a second drive shaft 62 rotates about the
axis of bearing 60. Mounting platen 6 is fixed to the housing 4 by
means of four flexible rubber legs 64. The mounting platen 6 is
substantially flat, and the legs 64 extend from a common major
surface of the platen 6 (the upper surface as shown in FIG. 10),
directed into the body of the housing 4. The flexible legs 64
extending from the mounting platen 6 are permanently fixed at their
housing end to the housing 4, i.e. they are not removable in use by
the operator. They are attached to the housing 4 by means of
clamping flanges 66 of the housing 4. The flexible legs 64 are
attached at their mounting platen end to the mounting platen 6 by
passing through apertures in hollow projecting portions 68 that
extend in the direction of the flexible legs 64 from the upper
surface of the mounting platen 6. The flexible legs 64 are provided
at their mounting platen 6 end with an internally screw threaded
hollow recess for attachment to a securing screw. The manner in
which this securement to the mounting platen is effected is
described in more detail below with reference to FIG. 11.
[0066] 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.
[0067] In FIG. 10 a first sanding platen, which is a random orbit
sanding head 8, is secured next to the mounting platen 6 onto the
drive shaft 62. Securement of the random orbit sanding head 8 is
achieved by a bolt 70 and washer 72. The bolt 70 passes through an
aperture in the sanding head 8, through aperture 74 in the mounting
platen (see FIGS. 12 and 13), and over the driving spindle of the
second drive shaft 62. The sanding platen 8 is located in a
parallel plane to the mounting platen 6, but is spaced from it, so
that there is no contact between the facing surfaces of the
mounting platen 6 and the sanding shoe 8. Therefore free rotation
of the sanding platen 8 is permitted about the bearing axis 60, and
the platen 8 exhibits a random orbit.
[0068] 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.
[0069] FIG. 11 shows the drive unit of the hand tool with an
orbital sanding platen 84 mounted in place of the random orbit
platen of FIG. 10. Also FIGS. 12 and 13 are perspective views of
the mounting platen 8 (which is common to both FIGS. 10 and 11) and
the sanding platen 84 (which is shown in FIG. 11, but not in FIG.
10).
[0070] FIGS. 12 and 13 show in more detail features of the mounting
platen 8, which remains on the housing when the platens 84 and 8
are interchanged. From these Figures it can be seen that the
mounting platen 8 is generally a blunt shoe shape, and is
substantially flat, with a peripheral lip 86 extending downwards
towards the sanding shoe 84. The large central aperture 74,
allowing it to be positioned around the second drive shaft,
radially distant therefrom, so there is no direct contact between
the mounting platen 6 and the second drive shaft 62, can also be
clearly seen in these Figures, as can the four hollow right
cylindrical portions 88, integrally formed with the surface of the
mounting platen 8, and projecting into the body of the housing 4
i.e. upwards as shown in the Figures. An inner lip 90 extends
downwards around most of the central aperture 74, and joins to the
outer peripheral lip 92 of the mounting platen 6 at two points 94
on one short side of the mounting platen 8.
[0071] 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.
[0072] 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 FIGS. 12 and 13 have a dual function; the pins 96
secure the legs 64 in place, and couple with an orbital sanding
head 84, in use, to prevent free rotation of that sanding head
(FIGS. 11 to 13).
[0073] 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 FIGS. 10 and 11). The externally screw
threaded bolt member 100 passes through the hollow central pin
member 96, and is shaped and sized to slide into the hollow pin
member until its head abuts the internal stop flange 98, and then
screw into inner hollow screw threaded cylindrical recesses at the
mounting platen end of the flexible legs 64. By this screw threaded
bolt member 100 the flexible legs 64 are therefore secured to the
mounting platen.
[0074] As best seen in FIG. 11, each pin member 96 is located
between part of the peripheral lip 86 and the inner lip 90 of the
mounting platen 6. The pin member 96 of the coupling means acts to
couple to the orbital sanding shoe 84 to prevent its free
rotation.
[0075] As shown in FIG. 11, when mounted on the drive unit, the
orbital sanding shoe 84 is secured to the spindle of second drive
shaft 62 by means of the same nut 70 and washer 72 used to secure
the random orbit sanding platen 8 of FIG. 10. The orbital sanding
shoe 84 is substantially flat, and is provided, on its upper major
surface in the orientation shown in the Figure, with coupling means
92 shaped to co-operate with the coupling means 96 of the mounting
platen 6. The coupling means 92 each comprise a hollow
right-cylindrical stub, projecting upwards from the surface of the
sanding shoe 84. The hollow right cylindrical projection 92 is
shaped so that it provides a recess into which the pin member 96 of
the mounting platen fits. One side of the cylindrical projection 92
on the sanding shoe 84 fits between the peripheral lip 86 of the
mounting platen 6 and the outer surface of the pin member 96 of the
mounting platen 6; and the opposite side of the cylindrical
projection 92 on the sanding shoe 84 fits between the inner lip 90
of the mounting platen 6 and the opposite outer surface of the pin
member 96 of the mounting platen 6.
[0076] 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.
[0077] 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.
[0078] 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 FIGS. 12 and 13)
being further apart from each other than those on the other lateral
side of the platens (the left as shown in the Figures).
[0079] 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.
* * * * *