referring now in detail to the drawings for the purpose of illustrating the present invention , the improved dental drilling assembly as shown in fig1 comprises an adjustable extension member 10 containing a body 11 , a threaded end portion 12 disposed at end thereof , an inner threaded hole 13 disposed at the other end thereof and a slot 14 extending across the end of the extension member . the apparatus further includes a triple arm drilling assembly 15 having large wheels 16 , small wheels 17 and 18 , a hand piece 19 connected to the small wheels 18 , a hanger 20 , a motor 21 having both a large pulley 22 and a small pulley 23 , and a belt 24 providing rotational communication between small wheels 17 and 18 , large wheels 16 and either the large or small pulleys 22 and 23 , respectively . in operation , if it is desired to use the large pulley 22 on the motor 21 , then the distance between the wheels 16 must be increased in order to make the pulleys 22 and 16 compatible and the belt 24 conveyed thereon in substantial parallel relationship . thus , the space between the wheels 16 is enlarged by first removing the bolts 25 and the wheels 16 from the drilling assembly and using the threaded end portion 12 to screw the adjustable extension member into the location from which the bolt 25 was removed . the wheel 16 is then placed over the other end of the adjustable extension member and the bolt 25 is screwed into the threaded end portion 13 of the extension member . by the use of the adjustable extension member , the space between the pulley wheel 16 can be substantially increased . by utilizing the adjustable extension members at both sides of the pulley wheel 16 , the distance between the pulley wheels can be further increased . the slot 14 is provided on the end of the adjustable extension member to provide a location for a screwdriver or other device for facilitating the attachment of the adjustable extension member . if it is desired to use the small pulley 23 on the motor , then the adjustable extension members can be removed and the pulley wheel 16 replaced in the manner discussed hereinabove . thus , the device of the present invention makes it possible to utilize a single drilling assembly with a motor which is provided with multiple sized pulleys in order to achieve different operating conditions . the invention being thus described , it will be obvious that the same may be varied in many ways . such variations are not to be regarded as a departure from the spirit and scope of the invention , and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims .
the present invention relates to a dental drilling assembly comprising an adjustable extension member which is utilized to vary the distance between pulley wheels of the drilling assembly to correspond to the size of the pulley utilized on the motor .