Backing pad for a hand-guided polishing or sanding power tool

Abstract

The invention refers to a backing pad (2) for a hand-guided polishing or sanding power tool, comprisinga support layer (4) made of a rigid material, the support layer (4) comprising a connection element (6) on its top surface (8) for connection of the backing pad (2) to a driving shaft (18) or an eccentric element of the polishing or sanding power tool,a damping layer (10) made of a resilient material, the damping layer (10) being fixedly attached to a bottom surface (12) of the support layer (4), andan adhesive layer (14) for releasable attachment of a polishing or sanding member to the backing pad (2), the adhesive layer (14) being fixedly attached to a bottom surface (16) of the damping layer (10)It is suggested that the bottom surface (12) of the support layer (4) is provided with reinforcement elements (24, 26, 28; 46; 50, 52) for enhancing flexural rigidity of the support layer (4), and the bottom surface (12) of the support layer (4) is further provided with recesses (30) formed between and at least partially limited by the reinforcement elements (24, 26, 28; 46; 50, 52), wherein during manufacture of the backing pad (2) the resilient material of the damping layer (10) enters into the recesses (30) and after curing of the resilient material entirely fills the recesses (30).

1 . A backing pad ( 2 ) for a hand-guided polishing or sanding power tool, comprising
 a support layer ( 4 ) made of a rigid material, the support layer ( 4 ) having a top surface ( 8 ) with a connection element ( 6 ) for connection of the backing pad ( 2 ) to a driving shaft ( 18 ) or an eccentric element of the hand-guided polishing or sanding power tool, and also having a bottom surface ( 12 ),   a damping layer ( 10 ) being made of a resilient material and having an associated bottom surface ( 16 ), the damping layer ( 10 ) being fixedly attached to the bottom surface ( 12 ) of the support layer ( 4 ), and   an adhesive layer ( 14 ) for releasable attachment of a polishing or sanding member to the backing pad ( 2 ), the adhesive layer ( 14 ) being fixedly attached to the associated a-bottom surface ( 16 ) of the damping layer ( 10 ),   characterized in that   the bottom surface ( 12 ) of the support layer ( 4 ) has reinforcement elements ( 24 ,  26 ,  28 ;  46 ;  50 ,  52 ) for enhancing flexural rigidity of the support layer ( 4 ),   the bottom surface ( 12 ) of the support layer ( 4 ) has recesses ( 30 ) formed between and at least partially limited by the reinforcement elements ( 24 ,  26 ,  28 ;  46 ;  50 ,  52 ), and   during manufacture of the backing pad ( 2 ), the resilient material of the damping layer ( 10 ) enters into the recesses ( 30 ), and after curing of the resilient material entirely fills the recesses ( 30 ).   
     
     
         2 . The backing pad ( 2 ) according to  claim 1 , wherein the reinforcement elements ( 24 ,  26 ,  28 ;  46 ;  50 ,  52 ) comprise a plurality of discrete pyramid-shaped elements ( 46 ;  50 ,  52 ) having a base surface in the form of a circle, a triangle, a rectangle, a square, or any other polygonal form, including an equilateral polygonal form. 
     
     
         3 . The backing pad ( 2 ) according to  claim 1 , wherein the reinforcement elements ( 24 ,  26 ,  28 ;  46 ;  50 ,  52 ) comprise reinforcement ribs ( 24 ,  26 ,  28 ). 
     
     
         4 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) have an at least discrete rotationally symmetric design in respect to a center ( 34 ) of the support layer ( 4 ) in at least some rotational angles about the center ( 34 ) of the support layer ( 4 ). 
     
     
         5 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a plurality of polygonal geometric elements ( 36 ), each polygonal geometric element ( 36 ) having a substantially polygonal rib design, and neighbouring elements ( 36 ) being located
 next to each others, or   offset in respect to each other, or   next to each other and offset in respect to each other.   
     
     
         6 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a honeycomb structure with a plurality of honeycombs ( 36 ) located next to each other, each honeycomb ( 36 ) having a substantially equilateral hexagonal rib design, and neighbouring honeycombs ( 36 ) sharing a common rib ( 24 ,  26 ,  28 ). 
     
     
         7 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a circular cobweb structure extending about a center ( 34 ) of the support layer ( 4 ), the cobweb structure having first reinforcement ribs ( 24 ) extending in a radial direction from the center ( 34 ) of the support layer ( 4 ) or parallel to the radial direction, and having second reinforcement ribs ( 26 ) extending in a circumferential direction around the center ( 34 ) of the support layer ( 4 ), substantially perpendicular to and intersecting the first reinforcement ribs ( 24 ). 
     
     
         8 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise first reinforcement ribs ( 24 ) extending in a radial direction from a center ( 34 ) of the support layer ( 4 ) or parallel to the radial direction along at least part of a distance between the center ( 34 ) of the support layer ( 4 ) and an outer edge ( 40 ) of the support layer ( 4 ). 
     
     
         9 . The backing pad ( 2 ) according to  claim 7 , wherein the first reinforcement ribs ( 24 ) are equally spaced apart in respect to each other in a circumferential direction. 
     
     
         10 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise second reinforcement ribs ( 26 ) extending in a circumferential direction around a center ( 34 ) of the support layer ( 4 ). 
     
     
         11 . The backing pad ( 2 ) according to  claim 7 , wherein the second reinforcement ribs ( 26 ) extend coaxially around the center ( 34 ) of the support layer ( 4 ). 
     
     
         12 . The backing pad ( 2 ) according to  claim 7 , wherein neighbouring second reinforcement ribs ( 26 ) are spaced apart from each other in a radial direction, including by an equal distance. 
     
     
         13 . The backing pad ( 2 ) according to  claim 3 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise third reinforcement ribs ( 28 ) which are embodied as circular, semi-circular or oval ribs located at least at some intersection points between radially extending first reinforcement ribs ( 24 ) or first reinforcement ribs ( 24 ′) extending parallel to a radial direction and circumferentially extending second reinforcement ribs ( 26 ), wherein the at least at some intersection points form centers of the third reinforcement ribs ( 28 ). 
     
     
         14 . The backing pad ( 2 ) according to  claim 13 , wherein the third reinforcement ribs ( 28 ) of neighbouring intersection points are spaced apart from each other. 
     
     
         15 . The backing pad ( 2 ) according to  claim 13 , wherein the third reinforcement ribs ( 28 ) have the same form and/or the same diameter. 
     
     
         16 . The backing pad ( 2 ) according to  claim 1 , wherein in a top view the backing pad ( 2 ) has a circular shape. 
     
     
         17 . The backing pad ( 2 ) according to  claim 1 , wherein the support layer ( 4 ) is made of plastic material, including a thermoplastic material with or without reinforcing fibres contained therein. 
     
     
         18 . The backing pad ( 2 ) according to  claim 4 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a plurality of polygonal geometric elements ( 36 ), each polygonal geometric element ( 36 ) having a substantially an essentially polygonal rib design, and neighbouring elements ( 36 ) being located
 next to each other, or   offset in respect to each other, or   next to each other and offset in respect to each other.   
     
     
         19 . The backing pad ( 2 ) according to  claim 4 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a honeycomb structure with a plurality of honeycombs ( 36 ) located next to each other, each honeycomb ( 36 ) having a substantially equilateral hexagonal rib design, and neighbouring honeycombs ( 36 ) sharing a common rib ( 24 ,  26 ,  28 ). 
     
     
         20 . The backing pad ( 2 ) according to  claim 4 , wherein the reinforcement ribs ( 24 ,  26 ,  28 ) comprise a circular cobweb structure extending about a center ( 34 ) of the support layer ( 4 ), the cobweb structure having first reinforcement ribs ( 24 ) extending in a radial direction from the center ( 34 ) of the support layer ( 4 ) or parallel to the radial direction, and having second reinforcement ribs ( 26 ) extending in a circumferential direction around the center ( 34 ) of the support layer ( 4 ), substantially perpendicular to and intersecting the first reinforcement ribs ( 24 ). 
     
     
         21 . The backing pad ( 2 ) according to  claim 10 , wherein the second reinforcement ribs ( 26 ) extend coaxially around the center ( 34 ) of the support layer ( 4 ). 
     
     
         22 . The backing pad ( 2 ) according to  claim 10 , wherein neighbouring second reinforcement ribs ( 26 ) are spaced apart from each other in a radial direction, including by an equal distance. 
     
     
         23 . The backing pad ( 2 ) according to  claim 11 , wherein neighbouring second reinforcement ribs ( 26 ) are spaced apart from each other in a radial direction, including by an equal distance.