Abrading – Frame or mount – Portable abrader
Reexamination Certificate
1998-12-03
2001-02-13
Scherbel, David A. (Department: 3723)
Abrading
Frame or mount
Portable abrader
C451S356000, C451S364000, C451S490000, C451S522000, C451S344000
Reexamination Certificate
active
06186878
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improvements in sanding apparatus. In particular, the present invention relates to a fixing member for fixing two sections of a base plate of a hand held sander together and a base plate incorporating such a fixing member.
2. Description of the Related Art
At present, there are many types of hand held sander available for tackling different types of job. In such equipment, sandpaper, glass paper etc. is attached to a base plate and the base plate is connected either to a handle so that it can be manually driven or it can be connected to a motor.
One type of base plate for a hand held, motor driven, reciprocating sander is made up of two layers, a top rigid layer which can be fixed to the motor etc. and a bottom compressible layer which has on its lower surface a surface fastening material so that suitable sandpaper can be easily attached to it.
One particularly adaptable type of sander has a base plate with a shape similar to that of a household iron. The main part of the plate is substantially oblong and tapers to a toe at its front end. A drawback of this type of plate is that the toe of the base plate gets very hot and thus, the toe section of the base plate wears out before the rest of the plate.
Previously, in order to overcome this problem, the lower layer has been supplied in two sections, a back lower section which is substantially permanently fixed to the rest of the base plate and a lower front toe section which is replaceable.
The lower front toe section is made out of a dense foam and is attached to the base plate via a rigid fixing member. The fixing member is in the form of a diamond shaped plate and is attached to the base plate by a screw. The hook part of a hook and loop fastener is glued to the fixing member, and the lower front toe section has a complementary fastener portion on one surface for fixing it to the fixing member, and a fastener portion on the other surface for attachment of the sanding sheet.
This type of arrangement has its disadvantages. Many stages are involved in the fabrication of the fixing member, specifically, a rigid plate is molded, hook type material is cut to the required shape and then the hook type material is glued onto the rigid plate. As the fixing member is fairly small, this can be an awkward and relatively time consuming operation.
Secondly, in operation, as has been stated above, the point of the sander base plate gets very hot. This continual heat recycling of the adhesive can result in the strength of the base plate being seriously degraded and may cause the fixing member to fall apart. In addition, the dust generated during sanding can lodge in the adhesive when it softens due to the heat. Thus providing another mechanism by which the sander base plate can degrade.
SUMMARY OF THE INVENTION
The present invention overcomes the above problems in that the fixing member of the present invention has surface fastener means integral with the fixing member. Therefore, in a first aspect, the present invention provides a fixing member for joining a first section which forms part of a lower surface of a base plate of a sander to a second section of a base plate of a sander, the fixing member being rigid and substantially planar and being provided with surface fastener means on a surface to attach the first section to said fixing member, the surface fastener means being integral with the fixing member.
In some such types of sander, if a section of the base plate is experiencing considerable wear, the fixing member may also need to be replaced. Therefore, it is preferable if the fixing member is removably attached to the second section of the base plate of the sander.
At the time of sanding operation, a part of the first section which forms part of the lower surface of the base plate of the sander becomes very hot locally comparing to the remaining part, thus the surface fastener means disposed at a portion corresponding to the fixing member which fixes the first section to the part of the lower surface of the base plate is liable to be influenced. This may cause the sander to be useless.
Especially, in case that the fixing member is made of a thermoplastic synthetic resin material having a surface shape same as that of the part of the lower surface of the base plate, it is preferable to provide a section without surface fastener so as to have a gap between the lower surface of the base plate and the section without surface fastener, through which heat radiates, thus the part does not get hot.
However, if the section without surface fastener is made to be a mere flat surface where no surface fastener means is formed, there should be a step between the section without surface fastener and the remaining part, which may lead to uneven sanding. Therefore, it is preferable that there provided a projection shorter than the surface fastener means at the section without surface fastener of the surface fastener means of the fixing member. With such projection, the step does not exist and at the same time there still is the gap between the lower surface of the base plate and the section without surface fastener, effective heat radiation can be realized so as to prevent the part to be hot.
The above discussion has been mainly concerned with base plates which have a pointed front toe. Of course, the present invention is of use with any sander base plate where a localised heat source might degrade only a part of the base plate. However, the present invention is of particular relevance to the above described base plate. Therefore, it is preferable if the fixing member joins the first section to the second section such that the first section forms at least part of a pointed front toe of the base plate.
It has been mentioned above that a particularly useful design of base plate has two layers, a rigid upper layer and a compressible lower layer. Sandpaper can be attached to the whole of the lower surface of the lower layer. During many jobs, it is necessary to fit the sander into a narrow space or to sand right up to a corner. Therefore, it is preferable if the upper layer does not extend further than the lower layer a direction parallel to the lower surface of the base plate. Also, to provide rigidity, it is more preferable if the upper layer extends as far as the lower layer in any direction parallel to the lower surface of the base plate.
When both the first and second sections are joined, it is preferable if the sides of the fixing member do not extend over the sides of the lower layer. It is more preferable if the fixing member is provided substantially flush with the side edges of the base plate.
In the situation where the first section forms part of a pointed front toe of the base plate, it is preferable of the fixing member has a point such that it can be attached to the front of the base plate. More preferably the fixing member is attached so that it is flush with the sidewalls of the base plate.
The fixing member will wear over time and due to the heat involved it is more likely to wear at the front toe first. Therefore, it is highly preferable if the fixing member can be inserted in more than one way. For example, the fixing member could have two corners and shaped so the either of the corners could be located at the front point. This prolongs the life of the fixing member. Therefore, it is preferable if the fixing member comprises two or more corners.
It has been found that a particularly preferable design is a diamond shape where either of the two acute corners can be attached flush with the front point of the toe of the base plate.
The toes of the two acute corners of the fixing member are the parts which get hot most. Therefore, the toes may be made to be flat surfaces having no surface fastener means. Alternatively, there may be provided the projection shorter than the surface fastener means in the section without surface fastener.
The fixing member has a surface fastener molded into it. It is more preferable, if the surface fastening means comprises
Akeno Mitsuru
Herdman George Kenneth
Seki Masahiko
Takizawa Toshiaki
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
McDonald Shantese
Scherbel David A.
YKK Corporation
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