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
  • F16H—GEARING
  • F16H27/00—Step-by-step mechanisms without freewheel members, e.g. Geneva drives
  • F16H27/04—Step-by-step mechanisms without freewheel members, e.g. Geneva drives for converting continuous rotation into a step-by-step rotary movement
  • F16H27/045—Mechanism comprising a member with partially helical tracks
• • 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
  • F16H—GEARING
  • F16H35/00—Gearings or mechanisms with other special functional features
  • F16H35/10—Arrangements or devices for absorbing overload or preventing damage by overload
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/19—Gearing
  • Y10T74/19642—Directly cooperating gears
  • Y10T74/19698—Spiral
  • Y10T74/19828—Worm
  • Y10T74/19837—Intermittent motion
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/19—Gearing
  • Y10T74/19642—Directly cooperating gears
  • Y10T74/19847—Directly cooperating gears torque actuated safety devices

Definitions

• the invention relates to a mechanical transmission, in particular via a drive shaft rotatably drivable step gear for converting a rotary drive movement into a rotary drive movement following a predetermined motion law and removable on an output shaft, in which a spring-loaded safety clutch which is triggered in the event of an overload is arranged.
• Safety couplings are also used to protect gearboxes against damage from overload, of which a large number of designs have been developed.
• Such safety couplings can have, for example, two coupling elements which are forced into a positive or non-positive engagement by a biasing spring, one of which is non-rotatably coupled to the driving shaft and the other to the driven shaft of the rotary drive to be secured. The level of the release moment is determined by the preload of the
• Coupling elements in the urging biasing spring determined, ie is largely constant.
• the release torque of the safety clutch is accordingly set in gearboxes secured in such a way that it is below the maximum permissible torque calculated with regard to the strength of the gearbox. This ensures that the gearbox can never be overloaded.
• this does not take into account the fact that, in particular in the case of stepper drives with downstream complex kinematic drives, it is not the maximum load capacity of the transmission itself, but rather the stress in the components of the downstream kinematics that can be critical, the permissible load being dependent on the position of the connected ones also change kinematic terms.
• the triggering torque of the safety clutch must be set to the lowest torque permitted in the output system, although the low triggering torque determined in this way is only required in very specific operating states. In certain applications, it would also be expedient if the triggering torque could be changed as a function of the output torque.
• the invention has for its object to provide a transmission, and in particular a stepper transmission with a safety clutch, the trigger torque automatically adapts to predetermined operational requirements.
• this object is achieved according to the invention in that the spring pretensioning the safety clutch is supported on a pretensioning element which is movably held in the gearbox housing by a predetermined stroke in the direction of increasing or decreasing the spring pretension, and in that the pretensioning element is part of the The output of a cam or cam drive is whose drive cam or cam is rotatably coupled to the drive or output shaft.
• gearbox to be secured is a stepper gearbox with a globoid or cylinder roller arranged in the gearbox housing, on or in the circumferential surface of which a web or groove-shaped drive control cam is provided, with which the output gearshaft protruding radially from the circumferential surface of a driven pulley is evenly divided.
• the configuration is preferably such that the safety clutch arranged between the output disk and the output shaft has two coupling elements which are displaceable relative to one another and, depending on the displacement position, have a form-fitting engagement or are disengaged from one another, one of which rotatably with the one in turn rotatable on the Output shaft bearing driven pulley and the other rotatably coupled to the output shaft that one end of the bias spring is directly or indirectly supported on the coupling element which is displaceable relative to the other coupling element in such a way that the coupling elements are urged into engagement, and that the other end of the spring supporting prestressing element is connected to one end of a rocking lever which is pivotally mounted in the gearbox housing and which follows a sequence which scans the control surface of the drive curve or cam of the cam or cam drive member is coupled.
• a configuration is expedient in which the drive disk and the coupling element connected to it in a rotationally fixed manner are combined to form an integral component which is rotatable but non-displaceably mounted in the longitudinal direction on the output shaft, and the associated second coupling element which is connected to the output shaft in a rotationally fixed manner is displaceable in the longitudinal direction on the Output shaft is arranged.
• the configuration can then be such that the rocker arm with its one end is pivotable in the transmission housing with one arm about an axis running parallel to the drive axis in the area between the drive and the driven axes, which lever is located on or at the
• the drive cam or the cam of the cam or cam drive which is connected to it in a rotationally fixed manner, extends and in one of the Drive curve or the area opposite the cam is provided with the follower, the preload of the spring being introduced into its free end in the sense that the follower is urged into contact with the drive curve or cam, and that on the Rocker arm in the gearbox bearing axis a second two-armed lever is pivotally mounted, one lever arm is supported on the free end face of the non-rotatably but slowly displaceably mounted on the output shaft coupling element, while in its other end the bias of the spring is initiated in the sense that the end face of the coupling element supported lever arm end urges the coupling element into engagement
• the safety clutch arranged between the globoid or cylinder roller and the drive shaft has two displaceable relative to one another and, depending on the displacement position, in a form-fitting manner Interlocking or disengaged coupling elements, one of which is rotatably coupled to the drive shaft and the other rotatably coupled to the globoid or cylinder roller, which in turn is rotatably mounted on the drive shaft, so that one end of the biasing spring is directly or indirectly connected to the relative is supported on the other coupling element displaceable coupling element, that the coupling elements are urged into engagement, and that the biasing element supporting the other end of the spring is arranged at one end of a pivotally mounted rocker arm in the gear housing, which is connected to the St Your surface of the drive curve or the cam scanning follower is coupled.
• the position of the coupling elements and the drive cam or cam is reversed with regard to their assignment to the drive or output shaft.
• the globoid or cylinder roller and the coupling element connected to it in a rotationally fixed manner can then be combined to form an integral component which is rotatable but non-displaceably in the longitudinal direction, the associated second coupling element non-rotatably connected to the drive shaft then being displaceable in the longitudinal direction on the Drive shaft is arranged.
• the design of the special exemplary embodiment is such that the rocker arm has one end with a one-armed lever that is pivotable in the transmission housing in the area between the drive and output axes and parallel to the drive axis which extends beyond the drive cam or the cam of the cam or cam drive which is provided on or next to the driven pulley and is connected to it in a rotationally fixed manner and in its area opposite the drive cam or cam with which the drive cam or the cam cam sensing follower is provided, while in its free end the bias of the spring is initiated in the sense that the follower is urged into contact with the drive cam or cam, and that a second two-armed lever is pivotable on the axis supporting the rocker arm is stored, de A lever arm is supported on the free end face of the coupling element mounted in a rotationally fixed but slowly displaceable manner on the drive shaft, while the pretensioning of the spring is introduced into its other end in such a way that the lever arm end supported on
• Rocker arm or the free lever arm of the two-armed bels is conveniently such that at the free end of the rocker arm one end of a slowly displaceable through a bore in a provided at the free end of the associated lever arm of the two-armed lever component is pivotally articulated, and that the biasing spring on the section through which the bore passes Tension rod is under compression arranged compression spring.
• the preload it is then advisable to support the compression spring on its end facing away from the associated lever arm of the two-armed lever on a nut screwed onto a thread on the free end of the pull rod.
• the preload can then be changed by changing the screw-in depth of this nut, which is suitably countered by a second nut.
• the preset preload is of course also superimposed by the movement of the rocker arm that is removed from the control curve of the cam or cam drive.
• FIG. 1 shows a view, partly in longitudinal center section and partly in sectional planes offset from this, of a globoid step mechanism with an overload clutch controlled in terms of the triggering torque in the manner according to the invention
• FIG. 2 is a sectional view, seen in the direction of arrows 2-2 in FIG. 1, the output disk and the output shaft being additionally shown in half-section within the gear housing; and
• Fig. 3 is a view of the transmission, seen in
• the globoid stepper drives shown in the drawing as a whole, denoted by 10, has a gear housing 12 in which a drive shaft 14 is led out at one end from the gear housing and at a distance from the drive shaft at right angles to it, one is also offset at one end from the Gearbox housing 12 leading output shaft are rotatably mounted.
• the globoid roller 18 When the drive shaft 14 is rotated by an electric geared motor, for example, flange-mounted on its end protruding from the gear housing 12, the globoid roller 18 is also set in rotation and its rotation is transmitted from the control day 20 to the control bolts 24 engaging on it, whereby the course of the control web 20 of the globoid roller 18 determines the law of motion, ie the rotational speed and acceleration of the driven disk 22 and thus the driven shaft 16 that has just been generated.
• an electric geared motor for example, flange-mounted on its end protruding from the gear housing 12
• the course of the control web in stepper drives of the type shown being often selected such that the output disc 22 from a standstill period first accelerate inclined, then speed constant and then again rotated to a standstill.
• the globoid stepper gearbox corresponds to known transmissions of this type, which is why, in a more detailed description of the manner of mounting the drive and output shafts in the housing and the special design of the control bolts arranged on the output disk, as on the flanks of the control web Globoid roller rolling "roller bolts" can be dispensed with. All that needs to be mentioned is that the gear housing 12 is open on its end face facing the globoid roller 18, although the opening is closed by a screwed-on housing cover 25.
• the safety clutch is arranged on the output shaft 16, wherein - as can be seen in FIG. 2 - the output disk 22, which is rotatable but non-displaceable in the longitudinal direction, itself forms one of the coupling elements of the safety clutch.
• the second coupling element 26 is formed by a disk-shaped component which is fixed in terms of rotation, but can be moved slowly over a predetermined stroke on the output shaft and has a diameter corresponding to the diameter of the output disk 22.
• the driven disk 22 and the disk-shaped component have complementary end teeth 28 with radially extending teeth, the flanks of which are inclined in such a way that when a torque is transmitted from the driven disk 22 to the second coupling element 26 formed by the disk-shaped component, between the teeth a force component acting in the axial direction arises which displaces the second coupling element 26 from the toothed engagement with the driven disk 22, as long as a correspondingly larger opposite axial force is not applied to the second coupling element.
• This counterforce is generated by a prestressed spring 30, which can be seen in particular in FIGS. 2 and 3.
• This Coil spring 30, which is under compressive prestress, presses on the end of a lever arm of a two-armed lever 32 which is pivotably mounted on an axis 34 held in the transmission housing 12 between the input and output shafts parallel to the input shaft 14 and with the end of its other lever arm on the the end face of the coupling element 26 facing away from the end toothing.
• the spring 30, which is under compressive prestress, thus urges the coupling element 26 formed by the disk-shaped component onto the driven disk in such a way that a positive coupling is provided via the front toothing 28. Accordingly, the safety clutch is only triggered when the gearbox is driven and the sum of the axial components of the torque transmitted on the oblique tooth flanks of the spur gearing exceeds the preload of the spring.
• the two-armed lever 32 is, in the case of the exemplary embodiment shown in the drawing, designed as a double lever arranged on both sides symmetrically to the longitudinal center plane of the transmission, the spring-side ends of the two of the individual levers being connected by a crosshead 36 on which the spring 30 is supported.
• the spring 30 is held on a pull rod 38 which is slidably guided through a bore 40 in the crosshead 36 and is provided at the spring end with a thread 41 onto which a nut 42 is screwed, which is suitably secured by countering or in another way, which supports the end of the spring 30 facing away from the two-armed lever 32.
• a pull rod 38 which is slidably guided through a bore 40 in the crosshead 36 and is provided at the spring end with a thread 41 onto which a nut 42 is screwed, which is suitably secured by countering or in another way, which supports the end of the spring 30 facing away from the two-armed lever 32.
• the pull rod 38 is pivotally articulated on a transverse axis 44, which in turn is arranged at the free, swinging end of a one-armed lever 46, which in turn is provided by two symmetrical to the longitudinal central axis of the transmission on both sides and connected by the transverse axis 44
• the lever 46 is supported on the axis also supporting the two-armed lever 32 34.
• the individual levers of the lever 46 connected by the transverse axis 44 are each guided directly to the side next to the end faces of the globoid roller 18 and they each have a shoulder 48 projecting in the direction of the drive axis and a roller 50 at its free end is rotatably mounted, which each roll on the control surface 52 of a drive curve 54 formed on the respectively assigned end surface of the globoid roller 18.
• the shoulder 48 and the roller 50 thus form the follower of a cam or cam drive which, when the gear is running and thus revolving drive curve 54, results in an oscillating movement of the lever 46.
• the preload in the spring 30 also changes with this movement of the rocking lever 46, which results in a corresponding change in the force exerted on the second coupling element 26 formed by the disk-shaped component.
• the release torque of the safety clutch also changes in accordance with the course of the control surface 52 of the drive cam 54.
• the desired release characteristics for the safety clutch can thus be specified by suitably designing the course of the control surface 52.
• Type can be used in a corresponding adaptation, provided that their release force or release torque depends on the pretension of a spring, which can be changed in the manner described by a cam or cam drive.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)

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Publications (1)

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ID=6309529

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Cited By (2)

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Citations (2)

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• 1986
  • 1986-09-13 DE DE19863631215 patent/DE3631215A1/de active Granted
• 1987
  • 1987-09-09 EP EP87905752A patent/EP0281593B1/de not_active Expired - Lifetime
  • 1987-09-09 WO PCT/EP1987/000512 patent/WO1988002079A1/de active IP Right Grant
  • 1987-09-09 US US07/183,737 patent/US4881421A/en not_active Expired - Fee Related

Patent Citations (2)

Non-Patent Citations (1)

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