FIELD OF THE INVENTION

The present invention relates to a crank pressing machine and, more particularly, to a pressing machine provided with a lever mechanism of consecutive motion of a press slider.

BACKGROUND OF THE INVENTION

Crank presses for hot and cold forging and stamping are known in the art (see, for example, US 4646551) and belong now to public domain. In the field of heavy forging and stamping presses, the hot forging crank press of Tjazhmekhpress has nominal capacity of 16500 tons of force (http://www.tmp-press.com/products/die- forging/pgl /358/). Its counterpart of Sumitomo Heavy Industries, Ltd. generates force up to 8000 tf (https://www.shi.co.jp/stf/english/pro0101.html).

Analysis of the existing technical solutions indicates that enhancement of generated force is possible by means of upscaling the eccentric shaft, that has some constructive limits. Multi-crank arrangements are also too complicated and labor consuming.

The works of all friction forces in the crank-rod mechanism is relatively similar to the useful yield. Specifically, the slider stroke at deformation of an article to be treated is 4-5 times less than the displacement of the point of application the equivalent friction force along its trajectory. In this case, high values of efficiency are unachievable.

In crank presses, a large part of the rod stroke is used for providing a space for inserting a work-piece.

Thus, there is a long-felt need to provide a more powerful crank press characterized by high efficiency and free of the abovementioned drawbacks. SUMMARY OF THE INVENTION

It is hence one object of the invention to disclose a crank press with an adjustable stroke. The aforesaid press comprises: (a) a press frame having a frame slideways therewithin with a slider reciproc atively movable therealong and supported by a pneumatic cylinder; (b) at least two mutually synchronized crank drives configured for reciprocatively moving the slider along the frame slideways; each crank drive comprising a main motor, a flywheel, a controllable clutch, a pinion shaft, a first crank shaft and a connecting rod kinematically connected in series such that the connecting rod moves the slider in downward and upward manners.

It is a core purpose of the invention to provide the crank press further comprising a lever-crosspiece mechanism further comprising: (a) at least one pair of threaded guide stanchions secured within the frame bed; (b) a first crosspiece slidably mounted on the guide stanchions atop the slider; (c) at least two two-arm levers slidably movable along a lower surface of the first crosspiece; the shorter arm of the two-arm lever is hingedly connected to the slider; a longer arm of the two-arm lever is hingedly connected to a connecting rod nut by a rod nut arrangement; (d) at least one pair of first-crosspiece stop nuts engaged with threads of the guide stanchions and configured for arresting the cross-piece at the moment of applying a force to the slider by the lever; the first-stop crosspiece nuts are releasably kinematically connected to one of the main motor via worm gears driving the first-crosspiece stop nuts belonging to the first crosspiece; (e) a nut arrangement threadly movable along a distal terminal of the connecting rod;

While the longer arm of the two-arm lever is driven by the connecting rod upward, a shorter arm of the two-arm lever being slidably supported by the first crosspiece retained by the first-crosspiece stop nuts belonging thereto applies a force generated by the crank drive to the slider.

While the connecting rod moves downward, the shorter arm of the two-arm lever eases the force applied between the first crosspiece and the slider and allows the first crosspiece to descend; the first-crosspiece stop nuts driven by the worm gears follow the first crosspiece.

Another object of the invention is to disclose the crank press comprising at least one pair of slider stop nuts configured for arresting the slider and preventing a backblow due to an elastic deformation of an article to be pressed. The slider stop nuts are kinematically connected to one of the crank drives via worm gears. The worm gears driving the slider stop nuts are connected to the crank drive in parallel to the worm gears driving the first-crosspiece stop nuts via a differential transmission.

A further object of the invention is to disclose thecrank drive comprising at least one second crank shaft mounted in parallel with the first crank shaft.The first crankshaft and at least one second crankshaft are engaged with the pinion shaft and driven thereby.The crank drive comprises a rocker connected to crank pins of the first and at least one second crank shafts. A proximal terminal of the connecting rod is hingedly connected to a middle of the rocker.

A further object of the invention is to disclose the crank press comprising a connecting rod nut arrangement drive moving the connecting rod nut arrangement along the distal terminal of the connecting rod and configured for compensating displacement of the first crosspiece. The connecting rod nut arrangement drive comprises a threaded rod kinematically connected to the first crosspiece and rotatable within a stationary threaded bore according to the displacement of the first crosspiece, a splined shaft length- adjustable in order to compensate the periodic displacements of the connecting rod and kinematically connected to the threaded rod and engaged with the articulated shaft, the one engaged with a bevel transmission , the said transmission engaged with the connecting rod worm shaft , engaged with nut of rod nut arrangement such , that spatial positions of the first crosspiece and connecting rod nut arrangement are mutually coordinated.

A further object of the invention is to disclose thecrank press comprising an auxiliary reverse stroke drive further comprising an auxiliary motor, a switch clutch configured for coupling the differential transmission and worm gears driving the stop nuts to the crank drive and auxiliary motor in an alternative manner.

A further object of the invention is to disclose each the worm gear of the nut comprises a pneumatic cylinder accommodating a compressed gas therewithin and having a piston with a stick splinedly connected to the shaft of the worm gear such that the pneumatic cylinder receives non-linearity of slider motion. A further object of the invention is to disclose the crank press comprises a mechanism configured for switching the switch clutch at a back- stroke phase of the slider and vice versa.

A further object of the invention is to disclose the crank press comprising a lower switching mechanism for reversing the slider after reaching a lowest point of a working stroke thereof.

A further object of the invention is to disclose the crank press comprising an upper switching mechanism for reversing the slider after reaching a highest point of a working stroke thereof.

A further object of the invention is to disclose the at least one pair of stop nuts comprising a self-locking thread.

A further object of the invention is to disclose the crank press comprising: (a) a second crosspiece mounted on the guide stanchions; the second crosspiece mounted under the first crosspiece; (b) a slider table rigidly connected to the slider and movably mounted on the guide stanchions between the first and second crosspiece; (c) at least two first and two second two-arm levers oriented opposite to each other; the first and second two-arm levers are slidably movable over a upper surface of the slider table and a lower surface of the second crosspiece, respectively; the shorter arms of the first and second two-arm lever are hingedly connected to a lower surface of the first crosspiece and an upper surface of the slider, respectively; longer arms of the first and second two-arm levers are hingedly connected to the first and second connecting rod nut arrangements, respectively; (d) at least two pair of stop nuts thereon engaged with threads of the guide stanchions and configured for arresting the first and second cross-pieces at a moment of applying a force thereon by the levers; the at least two pairs of stop nuts are releasably kinematically connected to one of the crank drives via a differential transmission and worm gears driving the crosspiece nuts belonging to first and second crosspieces independently; (e) first and second connecting rod nuts arrangements threadly movable along a distal terminal of the connecting rod.

While the longer arms of the first and second two-arm levers are driven by the connecting rod upward, a shorter arm of the first two-arm lever eases pressure on the slider table and a shorter arm of the second two-arm lever slidably supported by the second crosspiece arrested by the nuts belonging thereto applies a force generated by the crank drive to the slider.The nuts belonging to the first crosspiece driven by the worm gears follow the first crosspiece.

While the longer arms of the first and second two-arm levers are driven by the connecting rod downward, the shorter arm of the first two-arm lever hingedly supported by a lower surface of the first crosspiece arrested by the stop nuts belonging thereto applies a force generated by the crank drive to the slider table and moves the slider.The shorter arm of the second two-arm lever eases pressure on the slider; the nuts belonging to the second crosspiece driven by the worm gears follow the second crosspiece.

A further object of the invention is to disclose a lifting machine comprising: (a) a base member, (b) a crank drive; and (c) a vertically movable slider.

It is a core purpose of the invention to provide the lifting machine further comprises a lever-crosspiece mechanism further comprising: (a) first and second stanchions vertically secured to the base member; second stanchion threaded therealong; and (b) first and second crosspieces movably mounted on the second stanchion; the second crosspiece mounted under the first crosspiece;the slider being movable along the first stanchion is supported by the first crosspiece; the slider being supported by a cantilever on an intermediate link which is a pipe with end spherical surfaces on it and then on a collar with the same accordant surfaces of the cross-piece to exclude a rigid connection in a transverse plane between the slider and the first crosspiece; the second stanchion is provided with a non-self-locking thread; each of the first and second crosspieces comprising a conical nuts mounted within a tapered bore of the first and second crosspieces; the nuts threadly coupled with the second stanchion; the conic nuts are stoppable on the second stanchion in a self-locking manner by a gravitational force applied by the crosspieces and a load to be lifted to the conic nuts within the bore and rotationally movable along the second stanchion in an non- self-locking manner by applying a force to the conic nut relative to the crosspiece in a direction of ejecting the conic nut out of the bore of the crosspiece; each of the first and second crosspieces comprising an arrangement for reducing the contact normal forces between the conic nuts and corresponding tapered bores thereof; and (c) a two-arm lever hingedly connected to the second crosspiece; the two-arm lever having a longer arm connected to the crank drive such that the crank drive swingingly moves the two- arm lever around a hinge axis thereof. While the longer arm terminal point of the two-arm lever is moved downward by the reciprocating drive, a short arm of the two-arm lever applies a force generated by the reciprocating drive to the first crosspiece such that the first crosspiece ascends and the spring-loaded conical nut belonging thereto follows the first crosspiece along the second stanchion.The second crosspiece hingedly supports the two-arm lever while the conical nut belonging to the second crosspiece is locked and the second crosspiece is steady relative to the second stanchion.

While the longer arm terminal point of the two-arm lever is moved upward by the crank drive, the second crosspiece is pulled up. The second crosspiece ascends along the second stanchion; the conical nut belonging to the second crosspiece rotationally follows the second crosspiece.

A further object of the invention is to disclose the lifting machine comprising a descending arrangement comprising an auxiliary drive and two releasing bushings kinematically connected to the auxiliary drive; the two releasing bushings are configured for reduction of a contact normal forces between the tapered bores and the conical nuts such that a friction force between the tapered bores and the conical nuts is reduced.

A further object of the invention is to disclose the auxiliary drive which is a manual drive.

A further object of the invention is to disclose a lifting machine comprising: (a) a base member, (b) a crank drive; and (c) a vertically movable slider.

It is a core purpose of the invention to provide the lifting machine further comprises a lever-crosspiece mechanism further comprising: (a) first and second stanchions vertically secured to said base member; second stanchion threaded therealong; and (b) first and second crosspieces movably mounted on said second stanchion; said second crosspiece mounted under said first crosspiece; said slider being movable along said first stanchion is supported by said first crosspiece; said slider being supported by a cantilever on an intermediate link which is a pipe with end spherical surfaces is supported through this pipe on the accordant spherical surfaces of a collar of the said cross-piece to exclude a rigid connection in a transverse plane between said slider and said first crosspiece; the second stanchion is provided with a non- self-locking thread; each of the first and second crosspieces comprising a multidisc clutch nuts mounted within bores of the first and second crosspieces; each of said multi-disc clutch nuts having internal engagement discs engageable with external engagement disks of bores in said first and second crosspieces; and said the multidisc clutch nuts threadly coupled with the second stanchion; the multi-disc clutch nuts are stoppable on the second stanchion in a self-locking manner by a gravitational force applied by said crosspieces and a load to be lifted to the multi-disc clutch nuts within the bores and are rotationally movable along the second stanchion in a non-self-locking manner by applying a force to said multi-disc clutch nut relative to said crosspiece in a direction of ejecting said multi-disc clutch nut out of said bore of said crosspiece; each of the first and second crosspieces comprising an arrangement for reducing the contact forces between the clutch disks thereof; and (c) a two-arm lever hingedly connected to said second crosspiece; said two-arm lever having a longer arm connected to said crank drive such that said crank drive swingingly moves said two-arm lever around a hinge axis thereof.

While said longer arm terminal point of said two-arm lever is moved downward by said reciprocating drive, a short arm of said two-arm lever applies a force generated by said reciprocating drive to said first crosspiece such that said first crosspiece ascends and said multi-disc clutch nut belonging thereto follows said first crosspiece along said second stanchion; said second crosspiece hingedly supports said two-arm lever while said multi-disc clutch nut belonging to said second crosspiece is locked and said second crosspiece is steady relative to said second stanchion.

While said longer arm of said two-arm lever is moved upward by said crank drive, said second crosspiece is pulled up; said second crosspiece ascends along said second stanchion; said multi-disc clutch nut belonging to said second crosspiece rotationally follows said second crosspiece.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments is adapted to now be described, by way of nonlimiting example only, with reference to the accompanying drawings, in which

Fig. 1 is a schematic block diagram of a crank press; Fig. 2 is a kinematic scheme of a crank press provided with a nut-retainable crosspiece;

Fig. 3 is a kinematic scheme of a crank press provided with a nut-retainable crosspiece and a slider;

Fig. 4 is a kinematic scheme of a multi- stanchion embodiment of the crank press shown in Fig. 3;

Fig. 5 is a sketchy front view of a crank press provided with nut-retainable crosspiece and slider;

Fig. 6 is a side view of a crank press provided with a nut-retainable crosspiece and a slider;

Fig. 7 is a kinematic scheme of a crank press provided with the nut-retainable crosspieces and with not-retainable by nuts slider and slider table;

Fig. 8 is a sketchy model of a crank press provided with nut-retainable crosspieces and with the not retainable by nuts slider and slider table;

Fig. 9 is a kinematic scheme of a lifting machine provided with conic nut-retainable crosspieces; and

Fig. 10 is a kinematic scheme of an alternative embodiment of a lifting machine provided with multi-disc clutch nut-retainable crosspieces.

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided, so as to enable any person skilled in the art to make use of the invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, are adapted to remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a crank press and a lifting machine.

Reference is now made to Fig.l presenting a block diagram of crank press 300. Electric power feeder 302 is connected to control unit 310activates and disactivates drives and mechanism of crank press 300. The aforesaid press comprises at least two mutually kinematic chains 390a and 390b synchronized by linkage 360. Control unit 305 energizes main electric motors 310a and 310b transferring a rotational torque to clutches 320a and 320b which are activatable by control unit 310. Main electric motors 310a and 3 lObtransfer rotation to crank shafts 330a and 330b via clutches 320a and 320b. Consecutively connected main electric motors 310a and 310b, clutches 320a and 320b and crank shafts 330a and 330b form two parallel kinematic chains of crank drives of crank press. Crank shafts 330a and 330b convert rotational movement into reciprocal movement of connecting rod-lever mechanisms 340a and 340b configured to move a slider (not shown). The aforesaid slider is intermittently movable by connecting rod-lever mechanisms 340a and 340b. An elemental vertical displacement of the slider corresponds one revolution of crank shafts 330a and 330b. It should be emphasized that, in the course of slider movement, an articulation point between a connecting rod and a lever should be displaced along the connecting rod in accordance with vertical displacement of the slider. Tracking mechanisms 350a and 350b are configured for adjusting the position of the articulation point according to the current position of the crosspieces.

Reverse stroke of the slider is performed by auxiliary servodrive 315 connectable by switchable clutch 370. Numeral 380 refers to switching mechanism configured for switching the direction of motion of slider from the reverse stroke to the forward stroke and vice versa.

Reference is now made to Fig. 2 presenting a kinematic scheme depicting the basic embodiment 9of the present invention. Embodiment 9 comprises base 1 and at least two stanchions 2secured within base 1. Slider 27 is vertically movable in guiding ways 26. Crosspiece 8 is vertically movable along stanchions 2. Stop nuts 13 and 14 are rotatably movable along a threaded part of stanchions 2.

Numerals 10a and 10b refer to two parallel crank drives. Each of crank drives 10a and 10b includes consecutively connected main electric motor 43provided with a flywheel (not shown), controllable clutch 46, gear shaft 30 and crank shafts4. The flywheel functions are for dynamic balancing of the mechanism and as kinetic energy storage element for a press operation. After energizing main electric motor 43 by the control unit (not shown) and spinning the flywheel up to the predetermined rpm, clutch 46 controlled by the control unit couples the flywheel with gear shaft 30. The aforesaid gear shaft 30 is permanently engaged with two crank shafts 4. One crank shaft 4 belonging to crank drive 10a is kinematically linked by synchronizing bar 47 to one crank shafts 4 belonging to crank drive 10b such that phases of shaft rotation is synchronized.

Numeral 3 refer to rocker interconnecting crank pins 115 of crank shafts 4driven by gear shaft 30. Connecting rods 5 are hingedly secured to rocker 3. Levers 6 are hingedly to connecting rods 5. Levers 6 are slidably movable along a lower surface of crosspiece 8. Shorter arms7 of levers 6are hingedly connected to slider 27. Longer arml2 of levers 6are hingedly connected to rod nut arrangements l lthreadly movable along connecting rods 5.

As mentioned above, stop nuts 14 are engaged with threads along stanchions 2 and configured for arresting cross-piece 8 at the moment of applying a force to slider 27 by lever 6. Nuts 14 are releasably kinematically connected to one of crank drives via worm gears driving nuts 14 belonging to crosspiece 8. While longer arms 12of lever 6 are driven by connecting rods5 upward, shorter arms 7 of levers 6 being slidably supported by crosspiece 8 retained by stop nuts 14 belonging to crosspiece 8 apply a force generated by the crank drives 10a/ lObto slider 27. While connecting rods 5 move downward, shorter arms 7 of levers 6 ease the force applied between crosspiece 8 and slider 27 and allow crosspiece 8 to descend. Nuts 14 driven by the worm gears 78 follow crosspiece 8.

Movement of connecting rod 5 upward and downward is cyclically repeated at each turn of crank shafts 4. A number of cycles constitutes an operational stroke of crank press 9.

The nuts 14 are rotated by crank drive 10a. The kinematic chain comprises shaft 18, controlled by coupling clutch 53, gear arrangement 42, conic transmission 80 and worm gears 78, retained by pneumatic cylinder accommodating a compressed gas therewithin and having a piston with a stick connected to the worm shaft of the worm gear by a thrust bearing such that the pneumatic cylinder compensates non-linearity of slider motion. Nuts 14 are synchronized by chain linkage 118.

An operational stroke is defined by upper stop 50 and lower stop 64. The operational stroke is performed by means of several revolutions of cranks pins 115. Lower stop 64 is configured for stopping crosspiece 8 via rigid link 15.

After arresting crosspiece 8 by lower stop64 in lowermost position, slider 27 undergoes a last displacement downward and latchable stop 66 which in its lowest position is gripped by grip 54 due to slide clamp 55. At reverse displacement of slider 27 upward in the range of 5% of the last operation cycle, latchable stop 66 is retained in the lowest position by slide clamp 55. Left arm 56 terminal point of lever 68 pivoted at axis 67 is retained below and right arm 60 - above. Longer arm 12 of lever 6 via the kinematic chain 69 - 58-70-49-57-16 - 73 switches clutch 53 such that auxiliary drive 20 is connected to gearing shaft 18 which is a differential shaft. After switching clutch 53, auxiliary drive 20 moves slider 27 to the uppermost position. Then, slide clamp 55 frees grip 54. After that, a spring (not shown) resets latchable stop 66.

Upper stop arrangement, which includes stock 17, functions similar to the latchable stop, which is a lower stop arrangement. In this case, after clutch switching over, stop nuts 13 and 14 are driven by crank drive 10a via differentiating shaft 18 couplable by clutch 53 downward to follow the slider.

Pneumatic cylinder 59 is configured for applying to slider 27 a constant force directed upward vertically. Therefore, crosspiece 8 and slider 27 follow ascending crosspiece stop nuts 14. Stopping the crosspiece 8 in the course of the work stroke downward by arrester 64 provides improved accuracy of performed presswork.

In the course of an operational stroke, crosspiece 8 and slider 27 are alternately displaced downward along stanchions 2 and guiding ways 26, respectively. Levers 6 are connected to nuts 11 threadly movable along connecting rods 5 by nut arrangement 71 which comprises worm shaft 19 and bevel gear 21 driven by nut arrangement drive along a distal terminal of connecting rod 5 and configured for compensating displacement of crosspiece 8. The nut arrangement drive comprises a threaded rod 24 kinematically connected to crosspiece 8 and rotatable within stationary threaded bore 25 depending of a current displacement of crosspiece 8, a splined shaft 28 being length- adjustable in order to compensate periodic displacements of connecting rod 5 and articulated shaft 121. Rotation of threaded rod 24 is transferred to warm shaft 19 such that spatial positions of said first crosspiece 8 and nut arrangement 71 are mutually coordinated.

Hydraulic cylinders 23 and 29 are designed for balancing the forces applied to stanchions 2 in the course of press operation. Specifically, hydraulic cylinder 23 is hingedly connected to longer arm31 of first-order lever 22 displaceable around hinge 32. Shorter arm 33 of lever 22 is connected to stanchions 2 via hinge 34. Symmetrically located hydraulic cylinder 23 and lever 22 connected to stanchion 2 are not shown. Second-order levers 35 are angularly displaceable around hinge 32 and controlled by hydraulic cylinders 29. The function of levers 22 controlled by hydraulic cylinders 23 hydraulically interconnected to each other (not shown) is to balance the forces applied to stanchions 2 caused by plastic deformation of a billet.

Reference is now made to Fig. 3 presenting a second embodiment of the present invention of a crank press provided with nut-retainable crosspiece 8 and slider 27. Stop nuts 13 belong to slider 27 while stop nuts 14 to crosspiece 8. In the case of elastic deformation of the workpiece to be pressed, a return shock appears. In order to improve accuracy of the slider work stroke, nuts 13 following slider 27 during the operational stroke prevent the aforesaid slider 27 from rebound stroke. Similar to the embodiment depicted in Fig. 2, stop nuts are driven by warm gears 78. Contrary to the previous embodiment, the crank press comprises differential transmission 63 receiving a rotational torque from shaft 18 and dividing between shafts 122 and 123 which are kinematically connected with warm gears 78 via conic transmissions 80. The warm gears are retained by pneumatic cylinder accommodating a compressed gas therewithin and having a piston with a stick connected to the worm shaft of the worm gear by a thrust bearing such that the pneumatic cylinder compensates non-linearity of slider motion.

Reference is now made to Figs 4-6 to an embodiment of the crank press shown in Fig. 3 and comprising a number of pairs of stanchions 2. Expansion in the number of stanchions 2 and connecting rod 5-lever 6 arrangements provides increase in press tonnage without size gain of crank shafts and increase in operation efficiency.

Reference is now made to Figs 7a ,7b and 8 presenting an alternative embodiment of the present invention. Comparing the embodiments depicted in Figs 2 to 6 and Figs 7a, 7b and 8 the first ones can be interpreted as single-phase technical solutions while the last one is a two-phase crank press. Specifically, in Figs 2 to 6, one revolution of the crank shaft corresponds to one elemental displacement of a slider in the direction of the billet along the stanchions and a crosspiece following the slider. As explained below, one revolution of the crank shaft, in Figs 7a, 7b, 8 corresponds to two elemental displacements of a slider. Regarding the Fig. 8, it refers to a sketchy model of a crank press provided with nut-retainable crosspieces and with the not retainable by nuts slider and slider table.

During one revolution, the crank shaft forces the connecting rod one displacement upward in the first half of the cycle and one displacement downward in the second half of the cycle. In the first half of the cycle, the lever sends the slider downward while, in the second half of the cycle, the lever allows the crosspiece to follow the slider. Thus, there is a standstill period for the slider while the crosspiece reaches the slider.

Referring to two-phase embodiment shown in Figs 7a, 7b and 8 the lever-crosspiece mechanism comprises crank shafts 112, connecting rod 93, second-order lever 96, second-order lever 106, first crosspiece 8, second crosspiece 107, slider 90 and slider table 94 rigidly connected to slider 90. Lever 96 is disposed between first crosspiece 8 and slider table 94 while second lever 106 between second crosspiece 107 and slider 90. Positions of terminals of longer arms of levers 96 and 106 are defined by nuts 102 and 92 driven by worm gears 109a and 109b, respectively, while positions of terminals of shorter arms of the abovementioned levers 96 and 106 by crosspieces 8 and 107. Bushing 100 carries shackle 97 on its upper surface being rigidly connected to this shackle. Bushing 100 has a cylindrical surface which is in a hinge connection with bushing 101 connected to lever 96. Lower surface of internal window of shackle 97 carries bushing 104 rigidly connected to the aforesaid lower surface. Bushing 104 has a cylindrical surface which is in a hinge connection with bushing 103 supported by nut 102.

Bushings 100 and 101, lever 96, nut 102 and bushings 103 and 104are mounted within a window36 of shackle 97.

Bushings 37 and 38 have cylindrical surfaces which are in a hinge connection. Bushing 38 is supported by nut 92 while bushing 37 is connected to lever 106.

Bushings 99 and 39 belonging to lever 96 are in a hinge connection with bushings 98 and 105, respectively. Bushings 40 and 48 belonging to lever 106 are in a hinge connection with bushings 41 and 51, respectively.

First crosspiece 8 and second crosspiece 107 are provided with stop nuts 14 and 13 respectively. While the longer arms of the levers 96 and 106 are driven by connecting rod 93 upward, a shorter arm of lever 96 via busing 99 and 98 eases pressure on slider table 94. Shorter arm of lever 106 slidably supported via bushing 40 and 41by second crosspiece 107 arrested by the stop nuts 13 belonging thereto applies a force generated by the crank drive to slider 90. Stop nuts 14 belonging to first crosspiece 8 driven by the worm gears follow first crosspiece 8.

While the longer arms of levers 96 and 106 are driven by the connecting rod downward, the shorter arm of lever 96 supported via bushings 98 and 99by a lower surface of first crosspiece 8 arrested by stop nuts 14 belonging thereto applies via bushings 39 and 105a force generated by the crank drive to slider table 94 and moves slider 90 connected to slider table 94 by means of elongate members of lever 96. The shorter arm of second two-arm lever 106 eases the force applied to slider 90 via bushing 48 and 51 at the previous half-cycle. Stop nuts 13 belonging to second crosspiece 107 driven by the worm gears follow second crosspiece 107.

Lower stop 110 functions similar to lower stop 64 described at this page on above. Second crosspiece 107 has stock 52 connected thereto. When stock 52 bumps into lower stopper 110, movement of second crosspiece 107 stops. As position of second crosspiece 107 is precisely defined, the final displacement of slider 90 is forced by lever 106 supported by second cross-piece in its precisely defined position and driven by connecting rod 93 in the last half-cycle of the crank shaft revolution.

Reference is now made to Fig. 9 presenting a lifting machine , being an alternative embodiment of the similar to the presented above crank press mechanical arrangement, the unifying characteristics of which with the crank press are:

(a) a system of slider and first cross-piece , connected and moving together in the vertical direction, i.e. a system equivalent to the slider according to crank press cinematic schemes, (b) the second cross-piece, located under the first one, ,

(c) cross-pieces stop nuts, (d) lever-cross-piece drive, (e) threaded stanchion and (f) crank drive.

The lifting machine comprises base 219, stanchions 201 and 203 rigidly connected to base 219. Stanchion 203 has a non- self-locking thread. Stanchion 201 carries slider 202 movably mounted thereon. Stanchion 203 carries first and second crosspieces 215 and 230, respectively. The aforesaid crosspieces 215 and 230 are movable along stanchion 203.

The slider 202 is supported by its cantilcvcr229 on an intermediate link which is a pipe 216 with end spherical surfaces and - through this pipe - on the collar 227 of the cross-piece 215 to exclude a rigid connection in the transverse plane between the slider 202 and the cross-piece 215. making it possible for the slider to move in the transverse plane relatively the stanchion 201 within the required (in order to prevent jamming ) working guaranteed minimum clearance between them, having at the same time the reciprocal angular movements of the pipe 216 relative to the stanchion 203 due to sufficient constructive internal radial clearances between them.

So. the slider 202 - under the load action - puts pressure on first cross-piece 215 via pipe 216 to the collar of the cross-piece vertically downward.

First and second crosspieces 215 and 230 are supported by conic nuts 214 and 204, respectively accommodated in conformal bores within first and second crosspieces 215 and 230. Spring 222a supported by spring support 221a bumps onto conic nut 214 belonging to first crosspiece 215. Spring 222b supported by spring support 221b bumps onto conic nut 204 belonging to second crosspiece 230.

Numeral 205 refers to a guide brush preventing crosspieces 215 and 230 from skewing. Kinematic pairs 218 are designed for stabilizing crosspieces 215 and 230 in horizontal plane and preventing them from rotation around stanchion 203.

Referring to the ascending procedure, crank drive 226 moves a two-arm lever 206 which is angularly displaceable around hinge 228connected to second crosspiece 230. Lever 206 has a longer arm connected to crank drive 226 while its shorter arm is connected to connecting rod 207. Shorter arm , while moves upward, forces first crosspiece 215 via connecting rod 207 and support 213 to move upward either. Spring 222a pushes nut 214 along non-self-locking thread along stanchion 203 such that the aforesaid nut 214 follows first crosspiece 215 playlessly in its bore . A reverse motion of the shorter arm pulls second crosspiece 230 via hinge 228 upward, while the nut 214 is self-locked into the bore of the first cross-piece and therefore the cross-piece is locked on the stanchion . During the displacement of second crosspiece 230 upward, nut 204 follows second crosspiece 230from spring pressing. At the repeated move of the cross-piece 215 upward by lever 206 nut 204 is self-locked. As described above, slider 202 configured for carrying/lifting a load is connected to first crosspiece 215 and is lifted with first crosspiece 215 together.

When there is a need for descending slider 202, nuts 204 and 214 are forcedly unlocked by lever 225. The kinematic chain activating the descending procedure is the following. Bracket support 220 is hingedly connected to thrust washer 223. Lever 225 after inclining the pushbar 21 Idisplaceably within guideway 210, relative to bracket support 220, rotates then the pushbar 211, loaded by spring 212, together with the bracket support downward around the hinge connection of bracket support 220 to the bushing223. The aforesaid pushbar211 is provided with wedge surface 232 configured when being in mechanical contact with surface 231 of crosspiece 215 for applying a force to crosspiece 215 relatively the nut 214. Specifically, the abovementioned arrangement functions as a clamping mechanism which applies a force to nut 214 relative to crosspiece 215 in the direction of ejection of nut 214 from crosspiece 215 and unlocks it. Then, bracket support 220 descending together with crosspiece 215 via stock 209 presses lever 208 kinematically connected with thrust washer 224. Lever 208 is angularly displaceable relative to crosspiece 230 such that an “ejecting” force is applied between crosspiece 230 and nut 204 via thrust washer 224. Nut 204 is unbraked and crosspiece 230 descends either.

Reference is now made to Fig. 10 presenting a kinematic scheme of an alternative embodiment of a lifting machine provided with a multi-disc clutch nut-retainable crosspiece. Instead conic nuts in Fig. 9, the multi-disc clutch nuts are used for retaining crosspieces 215 and 230 on stanchion 203. The multi-disc clutch nuts arrangement comprises: (a) hubs 214a and 204a on stanchion 203; clutch discs 233 ; the hubs 214a and 204a having non-self-braking internal thread corresponding to the previously mentioned thread on the stanchion 203; the hubs214a and 204a having external movable travel engagement with internal engagement said discs 233; (b) cross-pieces 215 and 230 having internal movable travel engagement with external engagement said disks 233. In the ready position the entire set when assembled is pressed by springs 222a and 222b.

Just after the ascending procedure and till the descending one beginning the entire set of friction discs is compressed with the amount of compression equal to the load . At the calculated amounts of diameters of the discs and the number of discs it ensures self-locking of the hubs against rotation relatively the crosspieces under any loads under the mentioned non-self-braking thread of the stanchion 203.

While the invention has been particularly shown and described with reference to an embodiment thereof, it will be appreciated by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention.

Appendix

List of References

1 base 23 hydraulic cylinder

2 stanchions 24 threaded rod

3 rocker 25 threaded bore

4 crank shaft 26 guiding ways

5 connecting rod 27 slider

6 lever 28 splined shaft

7 shorter arm 29 hydraulic cylinder

8 crosspiece 30 gear shaft

9 basic embodiment 31 longer arm

10a and 10b crank drives 32 hinge

1 Inut of the rod nut arrangement 33 shorter arm of lever 22

12 longer arm 34 hinge

13 stop nuts 35 second-order lever

14 stop nuts 36 window

15 rigid link 37 bushing

16 pull bar 38 bushing

17 stock of the upper stop arrangement 39 bushing

18 vertical shaft 40 bushing

19 worm shaft 41 bushing

20 auxiliary drive 42 gear arrangement

21 bevel gear 43 main electric motor

22 first order lever 46 controllable clutch synchronizing mechanism 90 slider bushing 92 nut stock- shaft 93 connecting rod upper stop 94 slider table 1 bushing 96 second-order lever stock 97 shade coupling clutch 98 bushing grip 99 bushing slide clamp 100 bushing left arm of lever 68 101 bushing lever 102 nut 8 stock 103 bushing pneumatic cylinder 104 bushing right arm of lever 68 105 bushing differential transmission 106 second-order lever lower stop 107 second crosspiece6 latchable stop 109a worm shaft axis 109b worm shaft8 lever 110 lower stopper9 stock 112 crank shaft lever arm 113fly wheel 1 rod nut arrangement 114drive shaft2 threaded bore 115 crank pin 3 lever 118 chain linkage8 worm gear 121 articulated shaft0 conic transmission 122 shaft shaft 225 lever stanchion 226 crank drive slider 227 collar stanchion 228 hinge conic nut 229 cantilever a hub 230second cross-piece guide brush 231 wedge surface two-arm lever 232 wedge surface connecting rod 233clutch discs lever 300 crank press stock 302electric power feeder guideway 305control unit push bar 310a and 310b main electric motors spring 320a and 320b clutches support 330a and 330b crank shafts conic nut 340a and 340b connecting rod-lever mechanisms a hub

350a and 350b tracking mechanisms first crosspiece

360 synchronizing linkage pipe with end spherical surfaces

370 switchable clutch kinematic pair

380 switching mechanism base

390a and 390b kinematic chains bracket support a and 221b spring supports a and 222b springs thrust washer thrust washer