Patent Application
20060107814
This invention relates to a clamping device, and particularly but not necessarily exclusively to a clamping device for use in high precision wire erosion machinery.
The provision of clamping devices is essential in high precision wire erosion cutting machinery to ensure one or more articles being machined are located precisely in a pre-determined position. This ensures the accuracy of the cutting of said articles to within a few μm. The precision cutting machinery typically includes a flat and planar precision bed or worktable on which cutting of the articles takes place. A conventional clamping device includes a mounting head for mounting a spaced distance above the table and a holder or vice which is engaged with the mounting head. A levelling adaptor is located between the table and the mounting head to allow attachment and positioning of the mounting head above the table with accuracy in three axes with respect to the worktable.
A problem with conventional clamping devices is that the levelling adaptor is generally a complex arrangement of components which increases the complexity of the clamping device and makes the same prohibitively expensive to many potential customers. The vices allow horizontal clamping of workpieces only and since movement of a clamping member with respect to a further clamping member of the vice is restricted to a pre-determined length of the body portion or longitudinally of the vice, different sized vices need to be supplied for use with different sized workpieces. This also increases the cost associated with conventional clamping devices.
It is therefore an aim of the present invention to provide a clamping device which is simpler in form and less expensive to produce.
It is a further aim of the present invention to provide precision cutting apparatus including a clamping device which is simpler in form and less expensive to produce.
According to a first aspect of the present invention there is provided a clamping device for clamping one or more workpieces, said clamping device including a first portion having attachment means provided thereon for allowing attachment of the same directly to a work surface in use, and at least a second portion which is capable of being engaged with the first portion, said at least second portion forming at least part of or being associated with clamping means for clamping said one or more workpieces, and wherein the vertical and/or horizontal orientation of said clamping device is entirely dependent on the vertical and/or horizontal orientation of the work surface to which the clamping device is attached in use.
The work surface is preferably a work table of precision cutting apparatus.
Since the vertical and horizontal orientation of the worktable, surface or frame of the precision cutting apparatus is already precisely set by the apparatus manufacturers, the clamping device of the present invention does not require additional levelling adaptors to be supplied as in prior art devices. This makes the clamping device simpler to manufacture and less expensive to produce. In addition, maintaining the height of the work table typically equates to the most efficient setting of the apparatus and thus allows the fastest cutting speeds to be achieved.
Preferably the engagement means for engaging the first portion with said at least second portion includes at least one channel passing between said first and said at least second portion in which connection means are inserted in use, said channel being provided at an acute angle to the horizontal.
Preferably the channel is provided at an angle which slopes towards an upper surface of a work surface to which the portions are attached in use.
The entrances of said channels on the engaging surfaces of said first and second portions are substantially aligned on engagement. The channels slope in a direction from a top surface of said second portion to a base surface of said first portion to form a substantially continuous channel when the first and second portions are brought into engagement together. The slope of this channel enables a tool used to manipulate the connection means, such as an alien key and/or the like, to easily access the entrance aperture of said second portion without being restricted by the work table. In addition, on securing of the connection means in the channels of said second and first portions, the second portion is caused to move in a downwardly direction towards the first portion, thereby allowing repeatability of the connection position and thus ensuring repeatability of the accuracy of the cutting process.
Preferably the first portion of said clamping device is clamped directly to a worktable, surface and/or frame, such as a surface of a work table of high precision cutting apparatus. In an alternative embodiment, the first portion is clamped to the work table via at least a third or further portion.
Preferably the attachment means of said first portion includes one or more apertures or channels for the location of screws or similar connection means therethrough.
In one embodiment the apertures on the first portion are substantially aligned with pre-defined apertures provided on a work table of high precision cutting apparatus for attachment thereto, thereby removing the requirement for a user to drill additional apertures in the work table. Thus, the spacing of the apertures on said first portion typically substantially corresponds to the spacing of apertures on the work table.
Preferably the engagement means for engaging the first portion to said second portion further includes at least one protrusion portion provided on one of said first or second portions which engages in at least one complementary shaped recess portion in the other of said first or second portions.
Preferably the at least one channel on each of said first and second portions is provided in surfaces of said recess and protrusion portions.
Preferably the connection means includes a screw or bolt which is inserted into said channel for engagement of said first and second portions together. Tightening of said screw or bolt in said angled channel, moves the second portion towards the first portion and thus towards the surface on which the first and/or second portions are to be attached in use.
Preferably the first portion can be provided in either a substantially horizontal orientation or a substantially vertical orientation in use.
Thus, the first portion can be orientated in a substantially parallel orientation with respect to a worksurface and/or can be orientated in a substantially perpendicular orientation with respect to a worksurface. This is in contrast to prior art clamping devices which can only be used in a substantially horizontal orientation or substantially parallel with respect to a work table.
In one embodiment the first portion is in direction engagement with a suitable surface in use, such as an upper surface of a work table of precision cutting apparatus.
In an alternative embodiment at least a third portion is provided between the suitable surface and said first portion. The third portion engages said first portion in a similar manner to the engagement between the first and second portions.
With the first portion in a substantially vertical orientation, the second portion typically engages with a side surface thereof. Thus, the first portion is typically in the form of an elongate arm which is located substantially perpendicularly to an upper surface of a work table or other suitable surface. A protrusion portion or recess portion, typically elongated in form, is provided longitudinally of said arm and a complementary recess portion or protrusion portion is provided on said at least second portion and/or third portion for engagement therewith.
Preferably a plurality of apertures or channels are provided on said protrusion or recess portion at spaced apart intervals to allow connection means in the form of a screw, bolt or similar to be located through the second and first portions. This allows a plurality of at least second portions or third portions to be attached thereto in a stacked arrangement, thereby allowing firm clamping of a single workpiece and/or allowing firm clamping of a plurality of workpieces, each workpiece being clamped by a separate second portion.
The apertures or channels are typically arranged longitudinally of said first portion.
The advantage of the vertically arranged first portion is that elongate workpieces can be clamped in said clamping device. For example, a second portion can be located adjacent the top of the workpiece and a further second portion can be located adjacent the bottom of the workpiece without the risk of the apparatus or workpiece tipping over or moving during machining. The workpiece can be any suitable height, such as between 100 mm-400 mm.
According to a second aspect of the present invention there is provided a clamping device for clamping one or more workpieces, said clamping device including a first portion having attachment means provided thereon for allowing attachment of the same to a worksurface, at least a second portion which is capable of being engaged with the first portion, said second portion forming at least part of or being associated with clamping means for clamping said one or more workpieces and wherein the engagement means for engaging the first portion with said at least second portion includes at least one channel passing between said first and said at least second portion in which connection means are inserted in use, said channel being provided at an acute angle to the horizontal.
According to a third aspect of the present invention there is provided a clamping device for clamping one or more workpieces, said clamping device including a first portion having attachment means provided thereon for allowing attachment of the same to a worksurface, at least a second portion which is capable of being engaged with the first portion, said second portion forming at least part of or being associated with clamping means for clamping said one or more workpieces and wherein the first portion can be provided in either a substantially horizontal orientation or a substantially vertical orientation in use.
According to a further aspect of the present invention there is provided precision cutting apparatus including a clamping device.
Reference to precision cutting apparatus includes wire erosion machining and/or the like.
Embodiments of the present invention will now be described with reference to the accompanying figures, wherein:
a-3d illustrate examples of different types of clamping members which can be used with the present invention;
Referring firstly to
The device 2 includes a first portion 4 for attachment directly to the worktable and a second portion 6 for engagement with the first portion. The second portion 6 includes a first clamping member 8 and a second clamping member 10.
In order to simplify the clamping device of the present invention compared to prior art devices, first portion 4 is attached directly to the worktable. Since the worktable is preset in a substantially flat and planar manner, attachment of first portion 4 directly thereto will ensure levelling of the clamping device 2 within acceptable tolerances for most applications.
A base surface 12 of first portion 4 is located parallel with and adjacent to a top surface of the worktable frame. Apertures 14 provided at either end 16, 18 of portion 4 allow the location of engaging bolts 20 therethrough. The spacing of apertures 14 is substantially complementary to the spacing of apertures provided in the work table frame, such that the engaging bolts can locate in both apertures 14 and the work table frame apertures. The engaging bolts are located in position in the direction of instalment of the first portion on the worktable frame.
Engagement means in the form of a protrusion portion 22 is provided on a side wall 24 of first portion 4. In this example, protrusion portion 22 is located substantially centrally of first portion 4 and has a narrowing taper in a direction away from first portion 4. A channel 26 is provided through protrusion portion 22, the opening of channel 26 being located on the surface which engages with the second portion 6 in use.
First clamping member 8 of second portion 6 is in the form of an elongate arm. Further elongate arms can be provided if required. The arm has a first end 28, a second end 30, a top surface 32, a base surface 34 and side walls 36, 38.
A recess portion 40 is defined in side wall 38 adjacent end 30 which is substantially complementary in shape to protrusion portion 22. Thus, in this example, recess portion 40 has a diverging taper in the direction towards first portion 4 to increase the ease of engagement of protrusion 22 into recess 40. In use, the surfaces of side walls 24, 38 are brought into engagement, such that the protrusion portion 22 engages in recess portion 40. This engagement is further secured via fixing means in the form of a bolt 42 which is located through a channel 44 passing from side wall 36 to side wall 38 in the recess portion. A bolt 42 can be located through said channel 44 and into channel 26, the channels 44 and 26 being arranged substantially in alignment on alignment of said protrusion and recess portions 22, 40.
Channels 44 and 26 are provided at an acute angle to the horizontal, as shown in
Apertures 46 can be provided on top surface 32 of clamping member 8 which pass through to base surface 34. These apertures allow the first clamping member 8 to be located directly to a work table 33 if required, as shown in
Once the first clamping member 8 is engaged with first portion 4, a workpiece 50 can be located between clamping members 8 and 10 adjacent end 28.
Clamping member 10 is a fraction of the length of clamping member 8 to allow access to be gained to engagement means/attachment means provided on member 8. Member 10 is provided substantially parallel to member 8 at an end opposite to the end at which the second portion 6 is joined to the worktable or first portion 4. Rotatable members in the form of clamping screws 52 and 54 are provided parallel to each and at spaced apart intervals between first clamping member 8 and second clamping member 10 to join the same together and to allow relative movement of the members. Movement of screw 52 allows relative movement of clamping member 10 with respect to clamping member 8 to allow a workpiece 50 to be located therebetween. Movement of screw 54 allows the clamping force between members 8 and 10 to be effected. This relative movement is in a direction substantially perpendicular to the longitudinal axis of the first and second clamping members. The length of screw 52 typically determines the size of workpiece 50 that can be located between the clamping members.
The opposing surfaces of clamping members 8 and 10 in
In
In
In
A further embodiment of the present invention is illustrated in
Thus, a base 106 of locating tower 102 is located on a top surface 104 of a work table 33 and is secured thereto via screws 108 located through apertures provided in base 106. The main body portion 110 of tower 102 extends substantially perpendicularly to the upper surface of said work table and said base 104. More specifically, body portion 106 is provided at an end 112 of base 10. Engagement means in the form of a protruding strip 114 is provided on surface 116 of portion 110. Strip 114 is provided longitudinally of tower 102 and a plurality of apertures/channels 118 located at spaced apart intervals therealong.
First clamping member 8 of second portion 6 can be joined to tower 102 via recess portion 40 and secured via an engagement screw 120 as described in
The advantage of clamping each workpiece of a plurality of workpieces separately is that each workpiece is capable of being removed from the cutting apparatus for inspection and/or measurement purposes during a pause in machining and then precisely relocated in position in the clamping device. In addition, the ability to machine a plurality of components simultaneously increases the productivity of the machining process.
The tower 102 can be joined to work table via a third portion 202, as shown in
Thus, it can be seen that the present invention can be used in both a substantially horizontal and/or vertical orientation as well as a singular and/or plural configuration, whereas prior art clamping devices of this nature, are restricted to only horizontal and mainly singular application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0424745.8 | Nov 2004 | GB | national |
