Rotary hammer driving mechanism
Hand tool with a shifting gear unit
Rotary hammer with variable hammering stroke
Apparatus for driving a drilling or percussion tool Patent #: 5052497
ApplicationNo. 037936 filed on 03/26/1993
US Classes:173/48, Adjustable to impacting device173/109, Rotated by hammer head or drive for hammer head173/201Pulsation caused by mechanical movement
ExaminersPrimary: Rada, Rinaldi I.
Attorney, Agent or Firm
Foreign Patent References
International ClassB25D 011/10
Foreign Application Priority Data1992-03-30 JP
AbstractThe invention provides an improved intermediate housing incorporated in a power driven hammer drill, which is light in weight, easily and safely handled, and uncostly manufactured. The intermediate housing of the invention includes a bearing member and a cylindrical piston housing member which are integrally composed of a synthetic resin having high tenacity and excellent heat resistance and wear resistance. The intermediate housing further includes a plurality of ribs radially extending from the piston housing member to give a sufficient strength durable to a stress applied onto the piston housing member. In the intermediate housing thus constructed, the bearing member has at least one opening for feeding an air flow generated by a fan while the piston housing member includes at least one air conduit for circulating the air flow. This structure efficiently prevents overheat and thermal deformation of the piston housing member and the bearing member in continuous operation of the hammer drill.