Split ring clamping arrangement

• US 5,074,724 A
• Filed: 02/28/1991
• Issued: 12/24/1991
• Est. Priority Date: 02/28/1991
• Status: Expired due to Fees

• Current Assignee: Ryobi North America (Techtronic Industries Company Limited)
• Original Assignee: Ryobi Motor Products Incorporated (Techtronic Industries Company Limited)
• Inventors: McCracken, Robert E.
• Primary Examiner(s): Howell, Daniel W.
• Application Number:
  US07/661,619
• Time in Patent Office: 299 Days
• Field of Search: 409/175, 409/178, 409/181, 409/182, 409/204, 409/206, 409/210, 144/134 D, 144/136 CX, 411/427, 411/184, 411/185, 411/186, 411/187, 411/189, 411/366, 403/344, 24/278, 24/279, 24/285
• US Class Current: 409/182
• CPC Class Codes: B27C 5/10 Portable hand-operated wood-milling machines; Routers
• CPC Class Codes: Y10T 24/1439 Radial screw
• CPC Class Codes: Y10T 409/306608 End mill [e.g., router, etc.]
• CPC Class Codes: Y10T 409/30784 including means to adustably position cutter

Abstract

A portable electric router having a depth of cut adjustment mechanism including an adjustment ring which engages a screw thread on the motor housing and rotationally engages the router base. There is further provided an arrangement for preventing relative rotation between the motor housing and the base. The adjustment ring is formed as a split ring with projections adjacent opposite sides of the split, each with a frusto-conical camming surface. A circular clamp knob mounted for threaded rotation on a bolt passing through the projections radially with respect to the router motor housing bears against the camming surfaces so as to squeeze the ring in order to effect a clamping action as the knob is moved inwardly. In order to provide limit stops for preset depths of cut, a pair of stop rings are provided which are angularly rotatable on the router base. Each of the stop rings includes an interference projection and the adjustment ring has a tab fixedly mounted thereon which extends to a point between the interfering projections. The stop rings may be fixed to the router base to limit the range of angular rotation of the adjustment ring.

Claims

1. In a router including a motor housing having an external cylindrical portion, said cylindrical portion having a first longitudinal region with a substantially smooth surface and a second longitudinal region having an external screw thread, a base having a cylindrical bore for slidably receiving therein said first longitudinal region of said motor housing cylindrical portion, and an adjustment ring including means for engaging said screw thread on said motor housing and means for rotationally engaging said base, said adjustment ring being split with an opening between two opposed ends;

clamp means for releasably securing said adjustment ring to said motor housing so as to maintain the position of said base relative said motor housing, comprising;

a first projection formed on said adjustment ring adjacent a first one of said opposed ends;

a second projection formed on said adjustment ring adjacent the second one of said opposed ends;

said first and second projections each being formed as respective mirror-image halves of a frusto-conical structure;

an adjustment ring clamp knob having an inner surface adapted to slidably engage the frusto-conical surfaces of said first and second projections; and

means for supporting said knob with said inner surface engaging the frusto-conical surfaces of both said first and second projections so that movement of said knob toward said adjustment ring draws said first and second projections toward each other and movement of said knob away from said adjustment ring allows said first and second projections to separate;

whereby movement of said adjustment ring clamp knob may be effected by an operator for selectively securing and releasing said adjustment ring with respect to said motor housing.

2. The clamp means according to claim 1 wherein said clamp knob has a central internally threaded boss and said supporting means includes a threaded member fixed against rotation with respect to said adjustment ring and threadedly engaged with said clamp knob boss.

3. The clamp means according to claim 2 wherein said surfaces of said first and second projections are shaped such that at a section taken along a plane orthogonal to said threaded member each of said surfaces describes an arc of a circle having a predetermined diameter irrespective of the position of said plane along said surfaces, the center of said circle varying linearly as said plane moves along said threaded member.

4. The clamp means according to claim 3 wherein said clamp knob inner surface is frusto-conical to provide substantial surface engagement with said first and second projection surfaces.

5. An arrangement for clamping a split ring to an interiorly disposed surface, said split ring having first and second opposed ends adjacent an opening therebetween, comprising:

a first projection formed on said split ring adjacent said first opposed end;

a second projection formed on said split ring adjacent said second opposed end;

said first and second projections each being formed as respective mirror-image halves of a frusto-conical structure;

a clamp knob having an inner surface adapted to slidably engage the frusto-conical surfaces of said first and second projections; and

means for supporting said clamp knob with said inner surface engaging the frusto-conical surfaces of both said first and second projections so that movement of said clamp knob toward said split ring draws said first and second projections toward each other and movement of said clamp knob away from said split ring allows said first and second projections to separate;

whereby movement of said clamp knob may be effected by an operator for selectively securing and releasing said split ring with respect to said interiorly disposed surface.

6. The arrangement according to claim 5 wherein said clamp knob has a central internally threaded boss and said supporting means includes a threaded member fixed against rotation with respect to said split ring and threadedly engaged with said clamp knob boss.

7. The arrangement according to claim 6 wherein said surfaces of said first and second projections are shaped such that at a section taken along a plane orthogonal to said threaded member each of said surfaces describes an arc of a circle having a predetermined diameter irrespective of the position of said plane along said surfaces, the center of said circle varying linearly as said plane moves along said threaded member.

8. The arrangement according to claim 7 wherein said clamp knob inner surface is frusto-conical to provide substantial surface engagement with said first and second projection surfaces.