Press-fit tube-connection system

A method of connecting spindle to a tube the method comprising the steps of

• punching a non-round hole in an exterior wall of a tube to create a perimeter edge bordering the non-round hole having in series a first end edge, a first side edge, a second end edge, second side edge connecting to the first end edge, the first and second end edges being about equal in length, the first and second side edges being about equal in length, and
• press-fitting an end portion of a spindle into the non-round hole to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube, the tube including a hollow interior region extending therethrough, the punching step including the steps of supporting the tube in a fixture and using a scissors punch to create the non-round hole in the exterior wall of the tube without inserting a mandrel into the hollow interior region in the tube during engagement of the scissors punch and the tube.

A method of connecting a spindle to a tube, the tube having a longitudinal axis extending therethrough, the method comprising the steps of

• punching a non-round hole in an exterior wall of a tube to create a perimeter edge bordering the non-round hole having in series a first end edge, a first side edge, a second end edge, and a second side edge connecting to the first end edge, the first and second end edges being about equal in length, the first and second side edges being about equal in length, and
• press-fitting an end portion of a spindle into the non-round hole to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube, the punching step including the steps of providing a scissors punch having spaced-apart first and second tube-piercing tips, orienting the scissors punch relative to the tube so that the first and second tube-piercing tips intersect a longitudinally extending alignment line lying on the exterior surface of the tube and in spaced-apart parallel relation to the longitudinal axis of the tube, and moving the scissors punch into engagement with the tube to establish in sequence initially two puncture holes in the exterior wall of the tube on said alignment line and then the non-round hole in the exterior wall of the tube.

A method of connecting a spindle having round end portion to a tube, the method comprising the steps of

• punching an exterior wall of a tube having a hollow interior region to form a hole in the exterior wall of the tube and form first and second tabs appended to the exterior wall of the tube and arranged to lie in spaced-apart relation to one another in the hollow interior region of the tube, and
• press-fitting the round distal end of the spindle into the hole and in engagement with the tabs to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube.

A method of connecting a spindle to a tube, the method comprising the steps of

• punching an exterior wall of a tube having a hollow interior region to form a hole in the exterior wall of the tube and form first and second tabs appended to the exterior wall of the tube and arranged to lie in spaced-apart relation to one another in the hollow interior region of the tube, and
• press-fitting a distal end of a spindle into the hole and in engagement with the tabs to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube, the tube having a longitudinal axis extending therethrough, the punching step including the steps of providing a scissors punch having spaced-apart first and second tube-piercing tips, orienting the scissors punch relative to the tube so that the first and second tube-piercing tips intersect a longitudinally extending alignment line lying on the exterior surface of the tube and in spaced-apart parallel relation to the longitudinal axis of the tube, and moving the scissors punch into engagement with the tube to establish in sequence two puncture holes in the exterior wall of the tube on said alignment line and the hole in the exterior wall of the tube.

A method of connecting a spindle to a tube, the method comprising the steps of

• punching an exterior wall of a tube having a hollow interior region to form a hole in the exterior wall of the tube and form first and second tabs appended to the exterior wall of the tube and arranged to lie in spaced-apart relation to one another in the hollow interior region of the tube, and
• press-fitting a distal end of a spindle into the hole and in engagement with the tabs to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube, the tube including a hollow interior region extending therethrough, the punching step including the steps of supporting the tube in a fixture and using a scissors punch to create the hole in the exterior wall of the tube without inserting a mandrel into the hollow interior region in the tube during engagement of the scissors punch and the tube.

A method of connecting a spindle having a round end portion to a tube, the method comprising the steps of

• punching a non-round hole in a tube, and
• press-fitting the round distal end of the spindle into the non-round hole to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation to the tube.

A method for connecting a spindle to a tube, the method comprising the steps of

• punching a hole in an exterior wall of a tube to create a perimeter edge bordering the tube, the perimeter having a first pre-determined shape, and
• press-fitting an end portion of a spindle having a second pre-determined shape different than the first pre-determined shape into the hole to establish a tight fit between the spindle and the tube retaining the spindle in coupled relation in the tube.