Drive with continuously adjustable speed variation

• US 4,048,864 A
• Filed: 07/23/1976
• Issued: 09/20/1977
• Est. Priority Date: 07/28/1975
• Status: Expired due to Term

• Current Assignee: Heberlein Maschinenfabrik AG
• Original Assignee: Heberlein Maschinenfabrik AG
• Inventors: Ritter, Helmut
• Primary Examiner(s): Gerin, Leonard H.
• Application Number:
  US05/707,960
• Time in Patent Office: 424 Days
• Field of Search: 74/230.17 F
• US Class Current: 474/28
• CPC Class Codes: F16H 9/18 only one flange of each pulley being adjustable

Abstract

A belt driving mechanism, providing a speed ratio that is infinitely variable between predetermined limits, of the type in which a belt embraces two pulleys adjustable in effective diameter depending on the separation of two conical discs, is described wherein an actuating element reciprocable between two abutments is mounted coaxially with the driving pulley which has an axially fixed disc and an axially adjustable disc. The actuating element carries a rod with a scale ring screwed onto its outer end, and to urge the axially adjustable disc towards the fixed disc, the actuating element moves the scale ring to take up clearance between itself and a thrust member connected by way of a thrust bearing with the adjustable disc and, on continued movement, to force the thrust member to move the adjustable disc. Each movement of the actuating element covers the full stroke between the abutments so that the movement of the disc is the difference between this stroke and the initial clearance of the scale ring, which clearance can be adjusted by turning the ring on the rod. The thrust member is a coaxial tube containing the actuating element, which may be a piston in an axially fixed cylinder mounted with an intervening journal bearing on a rotary shaft fixed to the axially fixed conical disc. The mechanism relieves the bearings of a motor that drives the shaft of any axial thrust. The speed ratio can be adjusted by the scale ring either when the drive is at a standstill or when it is working.

Claims

1. For use in a belt driving mechanism providing a speed ratio that is infinitely variable between predetermined limits, an adjustable pulley mechanism comprising a driving member rotatable about an axis, a first conical disc coaxially fixed to said driving member, a second conical disc coaxially mounted on said driving member to slide towards and away from said first conical disc, said conical discs being mounted to provide an annular wedge-shaped groove therebetween tapering towards said axis for receiving in said groove a belt having a wedge-shaped cross-section, a hollow cylindrical thrust member for thrusting said second disc towards said first disc mounted coaxially with said discs for axial movement, a thrust bearing interposed between said thrust member and said second disc, means holding said thrust member in a set position about said axis, an element mounted to reciprocate within said thrust member, two abutment members respectively mounted for limiting opposite ends of the reciprocating movement of said element, a rod connected to said element for reciprocation therewith, said rod protruding from said thrust member at an end thereof remote from said discs, an abutment member adjustably mounted on said rod beyond said thrust member, said abutment member being adapted for fixing to said rod in any one of a range of positions thereon and for abutting against said end of said thrust member on movement of said rod in a direction towards said discs, and means for actuating said element to move from one of said abutments to the other of said abutments while initially moving said abutment member, by way of said rod, into engagement with said thrust member and thereafter moving said thrust member and said second disc from an initial position axially towards said first disc, whereby the distance moved by said second disc is the difference between the total stroke of said reciprocable element between said abutment members and the distance moved by said abutment member prior to engaging said thrust member.

2. A pulley mechanism according to claim 1, in which said rod is provided at its end protruding from said thrust member with an external screw thread and said abutment member is formed with a mating internal screw thread whereby said abutment member is adjustable along said rod by rotation.

3. A pulley mechanism according to claim 1, wherein said element is a double-acting piston and the pulley mechanism includes a cylinder mounted within said thrust member and wherein said piston is reciprocable, said actuating means comprising conduits for conveying pressure fluid into and out of said cylinder to act on opposite faces of said piston.

4. A pulley mechanism according to claim 3, in which said cylinder is coaxially mounted with respect to said driving member by means locating said cylinder in a fixed position along said axis including a journal bearing interposed between said driving member and said cylinder.

5. A pulley mechanism according to claim 1, including means for adjusting the speed of movement of said reciprocable element.

6. A pulley mechanism according to claim 1, comprising a motor for rotating said driving member and means for automatically returning said element from said other of said abutments to said one of said abutments to return said second disc to said initial position, when rotation of said motor ceases.