US3584519A - Mechanisms for converting a rotary motion into linear motion - Google Patents

Mechanisms for converting a rotary motion into linear motion Download PDF

Info

Publication number
US3584519A
US3584519A US818518A US3584519DA US3584519A US 3584519 A US3584519 A US 3584519A US 818518 A US818518 A US 818518A US 3584519D A US3584519D A US 3584519DA US 3584519 A US3584519 A US 3584519A
Authority
US
United States
Prior art keywords
toggle
linkages
series
ram
linkage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US818518A
Other languages
English (en)
Inventor
Eugen Weber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3584519A publication Critical patent/US3584519A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F16H21/00—Gearings comprising primarily only links or levers, with or without slides
    • F16H21/10—Gearings comprising primarily only links or levers, with or without slides all movement being in, or parallel to, a single plane
    • F16H21/16—Gearings comprising primarily only links or levers, with or without slides all movement being in, or parallel to, a single plane for interconverting rotary motion and reciprocating motion
    • F16H21/18—Crank gearings; Eccentric gearings
    • 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
    • Y10T74/20—Control lever and linkage systems
    • Y10T74/20576—Elements
    • Y10T74/20582—Levers
    • Y10T74/20588—Levers toggle

Definitions

  • the invention is a set of series-connected toggle [31] 21517/68 mkages adapted to transform an mput rotary motron Into an output cyclic reciprocatory linear displacement having a predetermined dwell period over an arc of the input rotary motion.
  • Each toggle linkage in a set has a mean made" work- 5 MECHANISMS FOR CONVERTING A ROTARY ing position and a mean broken" working position, and has MOTION INTO LINEAR MOTION its one extremity mounted on a fixed pivot am.
  • the other ex 14 Chin, 7 Drawing Figs tremity of each toggle llnkage represents the output drive and,
  • the ram In a machine for molding articles in thermoelastic plastics, the ram is required to force a preformed slug of the plastic material into a product mold at a relatively high rate and then to hold the pressure for a short dwell period while the material in the mold freezes. It must then be withdrawn as quickly as possible and held back for a second dwell period during which both the product mold is opened for stripping of the formed product, and the next slug is placed in position ready for the next ramming stroke. The mold itself will also be withdrawn from the ramming position to a stripping position and returned in readiness for the next ramming stroke.
  • toggle linkages for the conversion of continuous rotary motion to cyclic linear motion has the advantage that the mechanical components are simple and light in construction, and that standard components and techniques can be adopted without difficulty.
  • the stress problems are also among the simplest to evaluate.
  • a toggle is a device having an effective lost motion" characteristic in the analysis of its dynamics when one end is journaled on a fixed pivot and the opposite end is utilized to provide the output motion.
  • This effective lost motion is obtained when such a toggle is driven slightly overcenter, the motion of the free or output end ofthe toggle being negligible for a significant deflection of the knee joint or angular displacement of the link journaled on the fixed pivot.
  • the rotary input motion has no dwell period corresponding to a dwell period in the cycle of the reciprocatory output, it is continuous from start to finish of each cyclewhich may coincide with one single revolution of the rotary input member-although the speed of rotation is not necessarily constant.
  • Another object of the present invention is to couple a plurality of toggle linkages in series to form a transmission set, each having one extremity journaled on a fixed pivot axis while the other extremity provides the output motion which is transmitted to the next toggle in the set or, in the case of the final toggle, to the component to be reciprocated.
  • a further object of the invention is to couple the output extremity of one toggle linkage to the knee joint of the next in such a way that, during each cycle of the rotary input drive, each toggle is driven overcenter to provide a period of lost motion at its output extremity.
  • Yet another object is to provide a set of toggle linkages connected in series in which two or more are simultaneously driven overcenter whereby the resultant output motion of the set is substantially zero over a predetermined arc of travel of the rotary input drive.
  • a still further object of the invention is to provide two or more sets of series-connected toggle linkages each driving its respective reciprocatory driven component, the linkages being arranged so that dwell periods in the reciprocatory mo tions of the several driven components overlap for a predetermined duration of the common rotary input drive.
  • FIGS. 1 to 7 are schematic diagrams of the toggle linkages controlling the ram and product mold slides at different points in their cycles.
  • the mechanism illustrated comprises a continuously rotating main drive crank I0 and a pair of colinearly reciprocable slides I2, 14, the slide 12 constituting a ram slide for carrying the ram (not shown) of a plastic molding machine and the slide 14 constituting a mold slide for carrying a product mold (not shown).
  • the crank 10 carries a crankpin 16 which traces a circular path 18 around the axis 20 of the crank drive shaft in the direction of the arrow R. This path is divided into four sectors. From the point 1 through the point 2 to the point 3 is a first dwell sector, during which the ram and mold slides are stationary at their points of nearest approach (FIGS. 1-3).
  • a retraction sector during which the ram slide 12 is retracted to the outer limit of its travel but the mould slide 14 just begins to retract (FIG. 4).
  • the third sector extends from the point 4 through the point 5 to the point 6 and constitutes a second and longer ram slide dwell period which occupies almost of the crank travel (FIGS. 4-6).
  • the ram slide 12 remains substantially stationary in its retracted position throughout this dwell period, but during the first part thereof, between the points 4 and 5, the mould slide 14 is fully retracted (FIG. 5) and during the second part, between the points 5 and 6, the mould slide 14 is again advanced (FIG. 6) almost to its forward limit position, which it reaches when the crankpin 16 reaches the intermediate point 7 (FIG.
  • the fourth sector extends from the point 6 through the point 7 to the point 1 and constitutes the ramming stroke during which the ram slide 12 advances rapidly towards the mould slide 14 and forces the slug of moulding material into the product mold.
  • the mechanism in each case includes two sets of toggles.
  • the set marked A govern the motions of the ram slide 12, and the set marked B govern the motions of the product mould slide 14.
  • Each toggle can pass through a unique operating position in which it is made" i.e., the two links of the toggle are collinear so that small deflections of the knee joint between the links produce no significant displacement or output motion of the free end of the toggle.
  • the made" position is deemed to extend over a range of positions of the knee joint such that the angle (in radians) between one link and the line drawn through the outer ends of the two links is substantially equal to the sine of that angle.
  • the degree of approximation of the actual made position of a toggle to the unique collinear position which can be tolerated in any given case may vary according to the tolerance imposed by the circumstances of use of the mechanism.
  • this limiting broken" position of the toggle represents an inoperative condition
  • the term broken is deemed to exclude both the aforesaid limiting condition and all approximations thereto in which the finite value of friction in practical working components of the mechanism is sufficient to preclude displacement of the free end of the toggle linkage against its normal working load by application ofthe available input force to the knee joint.
  • crankpin 16 is coupled by links 22, 24 to the knee of the respective first toggle linkage of the two sets or trains of toggles operating the ram slide 12 and the mould slide 14 respectively.
  • These first toggles are located on fixed pivots at AL, B1 respectively, the successive driven toggles of the set A being identified by their respective fixed pivots at A2, A3 and A4, while the second toggle of the mould slide train is located on a fixed pivot B2.
  • the pivots A4, B2 define the path of linear reciprocation of the slides 12, 14 which are required to approach each other for a ramming operation, remain in the approach position during the first dwell period and then separate to follow the cycle of motions described above with reference to the points 1 to 7 on the path 18 traced by the crankpin 16.
  • the toggle A] consists of links 28, 30, the link 28 being located by the pivot at A1.
  • the output of the first toggle A1 of the ram slide operating train has the moving end of its link 30 articulated to the second toggle A2 at the knee joint 32 thereof.
  • the position of the fixed pivot at A2 is chosen in relation to the other parts of the linkage so that when the first toggle Al is in its nominally made mean position" indicated by the chain line a,, the toggle at A2 is in its broken position.
  • the toggle at A2 consists of a short link 34 pivoted on the fixed pivot A2 and a long link 36 whose free end is articulated to the knee joint 38 of the toggle at A3.
  • This latter toggle consists of links 40, 42, the latter of which provides the output motion of the toggle at its point of articulation to the knee 44 of the fourth toggle of the train at A4.
  • the one link 46 of the latter is mounted on the fixed pivot A4 and the other link 48 is articulated to the ram slide 12.
  • the mould slide toggle train B1, B2 is somewhat differently arranged in that both toggles are simultaneously made or simultaneously broken.
  • the link 24 carried by the crankpin 16 is articulated to the toggle Bl at its knee 50, and this toggle consists oflinks 52, 54, the former being mounted on the fixed pivot B1 and the latter being articulated to the knee 56 of the second toggle B2 consisting of links 58, 60, the former being carried on the fixed pivot B2 and the latter being articulated to the mould slide 14.
  • This dwell period is achieved by the positioning and proportioning of the linkage Al such that it lies in its made” mean position as defined above and as represented by the chain line a,.
  • the angle between the shorter link 34 ofthe toggle A2 and the axis a is of the order of 35 and the linear displacement of the output end 38 of the link 36 is proportional to the sine of the variation of this angle between the positions of the linkages shown in FIGS. 1 and 3. Since this latter is very small, the displacement of the point 38 is correspondingly small. Since the angle between the link 36 of the toggle A2 and the link 40 of the toggle A3 is approximately a right angle, the displacement of the point 44 during the first dwell period is approximately equal to the displacement of the point 38 and, since the toggle A4 is "made," displacement of the slide 12 is insignificantly.
  • the crank is shown at position 5 in which the toggle B1 has now been broken to the maximum extent.
  • its output link 54 has pulled the knee 56 of the toggle B2 down to its fullest extent so that the toggle B2 is also broken.
  • This action pulls the mould slide 14 back to its fully retracted position shown in FIG. 5. This is the stroke during which stripping of the product takes place. Meanwhile, however, the linkage A has scarcely displaced the ram slide 12.
  • FIG. 6 shows the parts in position at the end of the second dwell period of the ram slide 12.
  • the toggle A2 has just passed through the limit of its made" position within the definition given above.
  • the toggle A3 is also about to break, and the ram slide 12 is in the identical position to that shown in FIG. 4 at the commencement of the second dwell period.
  • the slide 12 is only displaced through the relatively small portion 12 of its total stroke.
  • the second dwell period is utilized as a transfer period for displacing a newly moulded slug from its moulding position to a position in register with the cavity of the mould on the mould slide 14.
  • the mechanism provides, once per cycle of the input rotation, simultaneous dwell periods for two linearly mutually reciprocable slides, the dwell period of one slide 14 being of longer duration than the dwell period of the other slide 12. It also provides a second and longer dwell period for the other slide 12 over another portion of the input cycle. Furthermore, it ensures that the slides are substantially motionless throughout at least the period of overlap of the simultaneous dwell periods.
  • the mechanism Besides ensuring accurate relative displacement of the slides in their predetermined phase relationship as noted above, the mechanism also ensures that the necessary force is transmitted to the slides l2, 14 to achieve their required accelerations and to resist the designed loads at the mould. This involves the limitation of the extent to which any one toggle linkage can break so as not to approach too closely to the critical friction angle at which the toggle cannot be made" whatever the force applied to the knee.
  • a toggle linkage assembly for transforming an input rotary motion into an output cyclic reciprocatory linear motion comprising a plurality of interconnected toggle linkages, each of said linkages including a pair of links and a knee pivotally connecting each of said links together at the respective ends thereof, and each of said linkages having a fixed pivot at one end thereof;
  • a toggle linkage assembly as set forth in claim 3 wherein half of said linkages are in said made mean working attitude and half are in said broken mean working attitude.
  • a mechanism for moving a pair of slides in a reciprocal linear motion path from a common rotary motion comprising a first series of toggle linkages connected between the rotary motion and a first slide and a second series of toggle linkages connected between the :rotary motion and the second slide, each of said linkages having a pair of links, a knee pivotally connecting said links and a fixed pivot at one end thereof;
  • said first series of toggle linkages including a first linkage having said knee thereof connected to said rotary motion, a last linkage connected to the first slide at the end remote from said fixed pivot thereof, and the remainder of said linkages pivotally connect-ed at the ends remote from said fixed pivots thereof to said knee of an adjacent connected linkage;
  • said second series of toggle linkages including a first linkage having said knee thereof connected to said rotary motion, a last linkage connected to the second slide at the end remote from said fixed pivot thereof, and each end of said remaining linkages remote from said fixed points being pivotally connected to said knee of the adjacent connected linkage.
  • said rotary motion includes a rotatable drive crank and a pair of links coupled to an end of said crank, one of said links being pivotally connected to said first linkage of said first series of toggle linkages and the other of said links being pivotally connected to said first linkage of said second series of toggle linkage.
  • a mechanism comprising a first series of interconnected toggle linkages connected to said ram for reciprocating said ram
  • a common continuous rotary input drive connected in common to said first and second series of toggle linkages for actuating each said series of toggle linkages in response to a rotary motion of said drive to reciprocate said ram and said mold core in a predetermined sequence.
  • each said series of toggle linkages includes linkages having a pair of links, a knee pivotally connecting said links and a fixed pivot at one end, and wherein said knee of said first linkage of each series is pivotally connected to said rotary input drive and the remainder of said knees of said other linkages are pivotally connected to an adjacent connected linkage at the end remote from said fixed pivots thereon.
  • a system for driving a reciprocable ram and a reciprocal mold core in a product molding machine which includes a first series of interconnected toggle linkages connected to said ram for reciprocating said ram, a second series of interconnected toggle linkages connected to said mold core for reciprocating said mold core, and a common continuous rotary input drive connected in common to said first and second series of toggle linkages for actuating each said series, wherein said first and second series of toggle linkages are arranged to reciprocate said ram and said mold core in mutually timed cyclic reciprocatory motions along a common rectilinear axis in response to rotation of said rotary input drive in a sequence wherein said first series advances said ram towards said mold core during a first arc of travel of said rotary input drive, holds said ram in a first dwell period during a second contiguous arc of travel of said rotary input drive, retracts said ram during a third contiguous arc of travel of said rotary input drive and holds said ram substantially stationary in a second dwell period in
  • a mechanism for deriving a cyclic linear reciprocatory motion having a predetermined dwell period in each cycle of reciprocation from a continuously rotatable input drive member comprising at least one set of toggle linkages consisting of a plurality of toggles coupled in series, each toggle comprising two links articulated at their adjacent ends by a knee joint;
  • each toggle of said series having one end of one link journaled on said fixed pivot axis and the opposite end of the other link providing the output motion of said toggle;

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Transmission Devices (AREA)
US818518A 1968-05-07 1969-04-23 Mechanisms for converting a rotary motion into linear motion Expired - Lifetime US3584519A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB21517/68A GB1214715A (en) 1968-05-07 1968-05-07 Improvements in mechanisms for converting a rotary motion into linear motion

Publications (1)

Publication Number Publication Date
US3584519A true US3584519A (en) 1971-06-15

Family

ID=10164258

Family Applications (1)

Application Number Title Priority Date Filing Date
US818518A Expired - Lifetime US3584519A (en) 1968-05-07 1969-04-23 Mechanisms for converting a rotary motion into linear motion

Country Status (7)

Country Link
US (1) US3584519A (xx)
BE (1) BE726535A (xx)
CH (1) CH506002A (xx)
DE (1) DE1901047C3 (xx)
FR (1) FR1600175A (xx)
GB (1) GB1214715A (xx)
NL (1) NL6900043A (xx)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992008913A1 (en) * 1990-11-09 1992-05-29 Greencare Pty. Ltd. Drive linkage for agricultural device
EP2703691A1 (fr) * 2012-08-31 2014-03-05 Thales Dispositif de positionnement angulaire à trois points morts
JP2014048668A (ja) * 2012-08-31 2014-03-17 Thales 各々が２個の死点で層状に重なり合う２個の機械的動作伝達アセンブリーを含む角度位置決め装置
CN105443694A (zh) * 2015-12-19 2016-03-30 重庆泽田汽车部件有限责任公司 单侧驻留往复传动机构
CN114110111A (zh) * 2021-12-08 2022-03-01 青岛英派斯健康科技股份有限公司 一种行程倍率放大机构

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4343633A1 (de) * 1993-12-21 1995-06-22 Franz Otto Dr Ing Kopp Umlaufend antreibbares Getriebe zur exakten Führung eines Punktes auf einer Geraden oder einer Ellipse

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992008913A1 (en) * 1990-11-09 1992-05-29 Greencare Pty. Ltd. Drive linkage for agricultural device
AU664692B2 (en) * 1990-11-09 1995-11-30 Greencare Pty Limited Drive linkage for agricultural device
EP2703691A1 (fr) * 2012-08-31 2014-03-05 Thales Dispositif de positionnement angulaire à trois points morts
FR2995054A1 (fr) * 2012-08-31 2014-03-07 Thales Sa Dispositif de positionnement angulaire a trois points morts
JP2014048668A (ja) * 2012-08-31 2014-03-17 Thales 各々が２個の死点で層状に重なり合う２個の機械的動作伝達アセンブリーを含む角度位置決め装置
US9388886B2 (en) 2012-08-31 2016-07-12 Thales Angular positioning device with three dead centres
CN105443694A (zh) * 2015-12-19 2016-03-30 重庆泽田汽车部件有限责任公司 单侧驻留往复传动机构
CN114110111A (zh) * 2021-12-08 2022-03-01 青岛英派斯健康科技股份有限公司 一种行程倍率放大机构

Also Published As

Publication number Publication date
GB1214715A (en) 1970-12-02
FR1600175A (xx) 1970-07-20
DE1901047A1 (de) 1969-11-20
BE726535A (xx) 1969-07-07
DE1901047C3 (de) 1978-10-12
CH506002A (de) 1971-04-15
DE1901047B2 (de) 1978-02-23
NL6900043A (xx) 1969-11-11

Similar Documents

Publication Publication Date Title
US3584519A (en) Mechanisms for converting a rotary motion into linear motion
FR2395340A1 (fr) Procede et machine de tissage tridimensionnel pour la realisation d'armatures tissees de revolutions creuses
US2280587A (en) Press
US4242968A (en) Stepping advancing device adapted for use with component support tables and other purposes
BR8203719A (pt) Dispositivo de acoplamento especialmente para uma maquina textil
US2830456A (en) Periodic mechanism
US2783922A (en) Drive system for plastic metering apparatus and the like
US3548594A (en) Power-transmitting device to actuate the moving part of toys
US2482811A (en) Motion for warp knitting machines
US2472919A (en) Mechanical movement
US3187600A (en) Mechanical movements
US2618196A (en) Intermittent film movement with fast pulldown
US3609816A (en) Hydraulic clamping mechanism
US3326058A (en) Indexing mechanisms
US2595433A (en) Shaft driving mechanism for headers or like machines
US4300406A (en) Apparatus for driving a plurality of units
US613393A (en) Johannes th
US1975369A (en) Engine for operating presses
US365420A (en) widmer
US1108844A (en) Mechanical movement.
US3043156A (en) Variable speed repetitive cycle transmission mechanism
US4323151A (en) Article transfer mechanism
Davidson Analysis and synthesis of a slider-crank mechanism with a flexibly-attached slider
SU1165590A1 (ru) Литьева форма дл изготовлени полимерных изделий с продольными отверсти ми
US2571153A (en) Apparatus for converting reciprocating motion to rotary motion