Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D13/00—Friction clutches
  • F16D13/04—Friction clutches with means for actuating or keeping engaged by a force derived at least partially from one of the shafts to be connected
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D13/00—Friction clutches
  • F16D13/02—Friction clutches disengaged by the contact of a part mounted on the clutch with a stationarily-mounted member
  • F16D13/025—Friction clutches disengaged by the contact of a part mounted on the clutch with a stationarily-mounted member with a helical band or equivalent member with two or more turns embracing a drum or the like
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D23/00—Details of mechanically-actuated clutches not specific for one distinct type
  • F16D23/12—Mechanical clutch-actuating mechanisms arranged outside the clutch as such
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D23/00—Details of mechanically-actuated clutches not specific for one distinct type
  • F16D23/12—Mechanical clutch-actuating mechanisms arranged outside the clutch as such
  • F16D2023/123—Clutch actuation by cams, ramps or ball-screw mechanisms

Definitions

• the invention concerns couplings between mechanical shafts . These couplings are generally used to connect the ends of two aligned shafts so as to transmit a torque with possibility of making or breaking the connection even during operation.
• the coupling is formed of a helical spring that surrounds two opposing axial cylindrical com ⁇ ponent parts fixed to the two shafts, the drive shaft and the driven shaft .
• the ends of said spring are respectively coupled to two collars that surround the spring.
• the inner dia ⁇ meter of the spring is increased thus reciprocally freeing the spring from the two cylindrical components and these latter from each other, and this breaks the connection between the drive shaft and the driven shaft.
• Subject of the invention is a coupling device between mechanical shafts with a helical spring under tension around two opposing axial cylindrical transmission com ⁇ ponents fixed to the two shafts.
• the ends of said spring are tied to two collars, that form a pair, in contact at the front and surrounding the spring.
• the spring is wound up or unwound according to whether re ⁇ lative rotation of the two collars goes in the winding direction of the spring or in the opposite direction.
• the two collars are made to rotate in opposite directions by a third controlling collar which is round the first collar of the pair, said third collar comprising a number of triangular radial tabs whose apexes face towards the second collar of the pair.
• a number of raised trapezoidal-shaped pieces are placed close to the edge of the first collar with the smaller side indwards while a number of trapezoidal-shaped teeth project from the edge of the second collar of the pair, their smaller side facing towards the first collar.
• each tab will fit in between one side of a raised piece on the first collar and one side of a tooth on the second collar, thus caus ⁇ ing the two collars to rotate in opposite directions unwinding the spring and making the two mechanical shafts independen . If, however, the control collar is made to slide in the opposite direction, the spring, then allowed to contract, adheres to the cylindrical components on the ends of the shafts and the driven shaft will be drawn along by the drive shaft.
• the angles of the sides of the raised piaces and of the teeth on the pair of collars correspond with those of the tabs on the third control collar.
• the raised pieces and the teeth, respectively above the pair of collars, consist of substantially equal bodies each one being approximately hexagonal.
• Said hexagonal body comprises raised trapezoidal projec ⁇ tions on the cylindrical surface of " the edges and is fixed by its longer side to the longer sides of the teeth.
• Said collars are therefore practically reversable and the third control collar can be mounted, as preferred, on the first or on the second collar of the pair.
• the control collar is made to slide by a second-class traction lever, power being applied to one end of the lever wtrrje its intermediate part makes contact with the back of the control collar.
• the traction lever is controlled by a second lever, this being a first class control lever whose power is determined by the pull of a spring that puts the device in the released position. To determine the engaged position of the coupling pres ⁇ sure must be applied to an arm mounted on the resistance end of said second lever.
• the coupling is used here for a lawn mower.
• the engine is mechanically connected by a wormscrew and a toothed gear wheel fixed to one of the cylindrical trans ⁇ mission components.
• the second cylindrical component is fixed to the driven shaft onto which a gear is fitted that transmits the motion to the mower's drive wheels.
• the arm fixed to the second control lever is connected to a short bar articulated on the end of a front rod, for guiding the mower, by means of a metal wire that slides inside a sheath covering said rod.
• Fig.1 The invented coupling mounted on a lawn mower.
• Fig.2 Detail of a transmission box with the invented coupling in the 'released' position ', longitudinal section.
• Fig.3 Detail as in Fig. 2 in the 'engaged' position.
• FIG. 1 Perspective view of the 'released' coupling.
• FIG.5 Detail of the coupling in Fig.4, in perspective.
• FIG.7 Detail of the coupling in Fig.5, in perspective.
• Fig.8 An exploded perspective view of the coupling.
• Figure 1 shows a lawn mower 10 on which is mounted the coupling device 20 subject of the invention.
• the lawn mower has a chassis 11, front free wheels 12, rear drive wheels 13 and a central handlebar 14.
• the internal engine not seen in the drawing, drives the wheels 13 by means of a transmission box 15.
• the helical cylindrical spring 50 with outwardly turning radial ends 51 and 52 and whose inner diameter is slightly smaller than the outer diameter of said cylindrical components 30 and 40 so that,when idle, there is reciprocal adherence between said spring and said cylindrical components.
• Collars 60 and 70 are placed round said spring 50, their equal inner diameter being slightly greater than the outer diameter of the spring 50, their length being equal, about half the length of the. spring 50 whose ends 51 and 52 re ⁇ main lodged in the notches 61 and 71 respectively, cut in the outer edges of said collars 60 and 70.
• the tabs 81 fit, under pressure, between the raised pie ⁇ ces 72 on the collar 70 and the teeth 62 on the collar 60 ( Figures 2, 4, 5). In particular, one side of each tab 81 presses against
• This pressure is supplied by the helical spring 85 hooked to one end of the pin 86 in the box 15 while the other end is hooked to the end 91 of a first class lever 90 pivoted at 95, and to which is fixed an orthogonal arm 93 that acts on the end 101 of a second class ringwise traction lever 100 that surrounds the collar 80 pivoted at the other end 102 of said lever in the seat 104 of said box 15.
• the central portion 103 of said lever 100 is in contact with the back of the collar 80.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Springs (AREA)
• Quick-Acting Or Multi-Walled Pipe Joints (AREA)
• Mechanical Operated Clutches (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=11369098

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (5)

Family Cites Families (2)

• 1994
  • 1994-06-10 IT ITMI941221A patent/IT1270209B/it active IP Right Grant
  • 1994-07-14 EP EP94923039A patent/EP0765442A1/de not_active Withdrawn
  • 1994-07-14 AU AU72745/94A patent/AU7274594A/en not_active Abandoned
  • 1994-07-14 WO PCT/IT1994/000111 patent/WO1995034765A1/en not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events