Drilling machine

A drilling machine including a vertical support holding a top housing and a worktable below the top housing, a drilling member mounted on said top housing and extending downward, a motor mounted on said top housing, said motor having a driving shaft, a driven shaft mounted to said top housing and connected to said drilling member, a transmission mechanism interconnecting said driving shaft and said driven shaft, means for feeding said drilling member, and improvements wherein:

• said top housing is mounted movably on said vertical post to move upward or downward, said vertical post having a compression spring to urge said top housing upward, said feeding means including a rack member mounted on said vertical post, a horizontal operating shaft mounted in said top housing adjacent said rack member, a pinion mounted on said horizontal operating shaft and engaging said rack member, said pinion moving upward or downward when being rotated, an operating handle connected to said operating shaft so as to rotate said pinion, whereby said drilling member is fed when said top housing is moved downward by operating said handle;
• and
• said vertical post is hollow and encases a fixed vertical guide rod, said top housing having a hollow to receive a top portion of said vertical post, said top housing further having a bearing part above said vertical post, said bearing part having an opening to permit said vertical fixed guide rod to pass therethrough, said compression spring disposed in said vertical post around said vertical rod, said compression spring having a bottom end fixed to said vertical post and a top end connected to said bearing part.

A drilling machine including a vertical support holding a top housing and a worktable below the top housing, a drilling member mounted on said top housing and extending downward, a motor mounted on said top housing, said motor having a driving shaft, a driven shaft mounted to said top housing and connected to said drilling member, a transmission mechanism interconnecting said driving shaft and said driven shaft, means for feeding said drilling member, and improvements wherein:

• said top housing is mounted movably on said vertical post to move upward or downward, said vertical post having a compression spring to urge said top housing upward, said feeding means including a rack member mounted on said vertical post, a horizontal operating shaft mounted in said top housing adjacent said rack member, a pinion mounted on said horizontal operating shaft and engaging said rack member, said pinion moving upward or downward when being rotated, an operating handle connected to said operating shaft so as to rotate said pinion, whereby said drilling member is fed when said top housing is moved downward by operating said handle;
• and
• said transmission mechanism comprises:
• a variable speed driving pulley assembly having a first fixed cone-shaped disk and a first movable cone-shaped disk mounted on said driving shaft,
• a variable speed driven pulley assembly having a second fixed cone-shaped disk and a second movable cone-shaped disk mounted on said driven shaft,
• a belt interconnecting said driving and driven pulley assemblies,
• an adjustable rod mounted rotatably in said top housing and aligned coaxially with said driven shaft, said adjusting rod having a first end rotatably connected to a center portion of said second movable cone-shaped disk, a second end extending out of said top housing and a peripheral helical thread between said first and second end,
• a knob attached to said second end of said adjusting rod,
• an annular seat mounted on and extending out from said top housing, said annular seat having a through-hole to be permit said adjusting rod to pass therethrough and a projection means engaging said peripheral helical thread so that said adjusting rod moves axially when being rotated, and
• means for preventing said adjusting rod from rotation, provided adjacent said knob.