CN85104335A

CN85104335A - Prestressed takeup

Info

Publication number: CN85104335A
Application number: CN 85104335
Authority: CN
Inventors: 黄锡镛
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-06-03
Filing date: 1985-06-03
Publication date: 1987-02-18
Also published as: CN85104335B

Abstract

The present invention is a box steel beam, particularly the prestressed takeup of bridging crane main beam.This device is made up of tensioner and equalizer pulley two parts, and two of steel rope is wound on respectively on the shoulder of worm gear both sides, and is fixed in the exit skirt of worm gear both ends of the surface by the pipe and the pulley of beam bottom.Device of the present invention is not only applicable to the manufacturing of beam, reduces material, but also is applicable to the maintenance of lower torsion beam, makes reparation easy, and the duration is short.

Description

Prestressed takeup

The present invention is a kind of prestressed takeup of the box steel beam that is applicable to, particularly bridging crane main beam.

In existing technology, repair the bridging crane main beam downwarp, generally be to implement stretch-draw (referring to " handling machinery " 1976 the 5th phases " with the downwarp of prestressing method processing traverse crane " literary composition) by auxiliary tensioning equipment.This method generally is that single executing drawn, so the lacing wire of post-stretching is to the compressive deformation that beam produces, and the reinforcement stress of stretch-draw is lax before causing, causes the stress of every lacing wire not wait.Because every prestressing tendon is stressed separately, mutually noninterfere, so beam is when carrying, the stressed of reinforcing bar differs, and also it can't be adjusted.Usually adopt this method, after stretch-draw was intact, the termination wanted anchor tight or fastening with nut, and auxiliary tensioning equipment takes off.In the use of beam, find stress relaxation or the capable again stretch-draw of the then inconvenience of losing efficacy.When beam stress was out of shape, the lacing wire of fixed end place can produce additional bending stress along with deflection angle changes, and the load-carrying capacity of prestressing tendon is weakened.

Task of the present invention is to solve box steel beam and bridging crane main beam prestressed stretch-draw in making and keeping in repair; Beam in use, to prestressed lax or lost efficacy and carry out tensioning again; And lacing wire two fixed ends are because of the additional stress problem that distortion produced of beam.

Prestressed takeup of the present invention is divided into the two large divisions, i.e. the tensioner formed such as the bearing that is made of worm gear (1), worm-wheel shaft (5), worm screw (13), housing (7), thrust ball bearing (12), worm gear end face groove and steel ball (2), bearing inner ring (3), sliding shaft sleeve (15) and the equalizer pulley of being made up of pulley (18,20), sheave shaft (21), clamping plate (19), bearing (27), bearing pin (22) etc.Two parts are installed in the bottom, two ends of beam respectively.Steel rope by the garden pipe and the pulley of beam bottom, is wound on the worm gear abreast.Worm gear and worm screw are installed on the cast-in-block housing, have quantity on the shoulder of worm gear both sides and equate and symmetrical steel wire rope groove.The steel rope of reeling is introduced in one section introversion wire casing of worm gear end face, and the fag end casting is solid extremely in exit skirt (9).According to prestressed size, the steel rope number can be 2,4,6 ...Shoulder corresponding grooving centre distance in worm gear both sides equates with same steel rope bonded assembly pulley working diameter.Worm gear is subjected to have a groove on the end face of axial force, and steel ball (2) is housed in the groove, and bearing inner ring (3) is blocked in notch, and contacts with the inwall of housing supporting.One end of worm-wheel shaft is equipped with axle head baffle plate (8), prevents that the semi-open type housing from making its outside spreading because of the axial force of worm gear.The other end is drilled with an oil hole, and there is oil sealing screw (4) in the aperture, and oil outlet communicates with the worm gear oil groove.Worm screw is subjected to an end of axial force that one thrust ball bearing is housed, and the other end has a square tenon.Pulley, is contained among the clamping plate being subjected to take turns footpath arrangement from small to large by it on the force direction by sheave shaft.Back pulley (20) will arrive the two-fold wirerope diameter greatly than the groover rot diameter of front wheel (18).Clamping plate can rotate around bearing pin (22).One end of bearing pin is equipped with retaining spare (26).Bearing pin is loaded on the bearing (27), and each bearing all has reinforcement gusset (25) to support.

Prestressed takeup of the present invention is to control its stretching force according to the elongation of steel rope stretch-draw.Elongation △ l can be calculated as follows:

△l＝ (2Miηl)/(ADEK) （1）

M-drive torque in the formula.

The i-transmitting ratio.

η-driving efficiency.

The l-worm gear is to the horizontal throw of pulley center.

A-props up the steel wire basal area sum of steel rope.

The working diameter that the D-steel rope is reeled on shoulder.

The modulus of elasticity of E-steel rope.

The number of K-steel rope.

Can control stretching force by calculation of Prestress is N, and therefore maximum drive torque is:

Mmax＝ (ND)/(2iη) （2）

In advance should a given pre-fastening moment Mmin, according to the deadweight of steel rope, i.e. the weight q of unit length and known cable bent f, this value should be:

Mmin= (ql ²DK)/(16iηf) （3）

Drive torque Mmax and Mmin substitution formula (1) respectively try to achieve △ lmax and △ lmin value, thereby the number of turns that is rotated further worm screw just can be calculated by following formula

n＝ (（△lmax-△lmin）i)/(D π)

= (li)/(AEDπ) ( (N)/(K) (ql ²)/(8f) )（4）

The present invention has overcome the some shortcomings of common rear tension prestress technology.Drive many steel ropes of worm gear traction, its pulling force is equated, but also can adjust unbalance stress phenomenon in use by equalizer pulley.This device is packed on the beam, if prestress has lax or lost efficacy, can adjust at any time.When beam stress is out of shape, be wound on the steel rope on the shoulder of worm gear both sides, along with deflection can be done the angle variation, the steel rope that the other end is enclosed within on the pulley rotates with the variation of deflection angle around bearing pin together with clamping plate, thereby two fixed end not constraint in vertical direction, do not produce additional bending stress thus yet, thereby improved the load-carrying capacity of steel rope.

Prestressed takeup of the present invention is not only applicable to the manufacturing of box steel beam and bridging crane main beam, reduces material, but also is applicable to the maintenance of lower torsion beam, repairs easyly, and the duration lacks.

Description of drawings:

Fig. 1 is the tensioner of prestressed takeup.

Fig. 2 is the B-B cutaway view of the tensioner of prestressed takeup.

Fig. 3 is the scheme drawing that prestressed takeup is adopted in the manufacturing of beam.

Fig. 4 is the C-C schematic cross-section of Fig. 3.

Fig. 5, Fig. 6 are the equalizer pulleys of prestressed takeup.

Fig. 7 is the scheme drawing that prestressed takeup is adopted in the maintenance of beam.

Embodiment:

In order to prevent to cut off and grind away steel rope, reduce the friction force of stretch-draw, welding garden pipe (17) below strength plate (16) or support (28) makes it to become the garden face to contact with steel rope.When making or keep in repair, connect these garden face contact points and form a sagging meander line, make the sag f=L/1000 of beam meander line, the sag of maintenance beam meander line equals the downwarp value of beam and adds l/1000, like this, even after the stretch-draw, steel rope still keeps contacting with these contacts, to play the effect that reduces to vibrate.

The cutting length of steel rope should consider to control the maximum elongation amount of stretch-draw, must not form overlapping coiling during stretch-draw on the worm gear shoulder.With the steel rope of the every super stretch-draw of process, the equalizer pulley of the end by being installed in beam passes with leaving in peace mutually and arrives at the other end.Fag end with galvanized wire colligation jail, is put into exit skirt before breaking crotch, solid dead with Babbitt matal or plumbous casting.

On the groove of worm gear one end, adorn steel ball (2) and bearing inner ring (3).Steel rope is drawn through the introversion wire casing, is wound on symmetrically on the garden arc groove of worm gear both sides shoulder, worm gear is inserted to have assembled in the housing of worm screw then, wears with worm-wheel shaft and refills axle head baffle plate (8) after fixed.If make, tensioner is packed on the connecting panel (11) of force side band retaining step with screw (6).This plate is through after processing, and the jail is welded on the lower cover of beam in advance.The other end then uses cover plate (24) to press rubber washer (23) to shut breach, makes the case beam become obturator.

The control stretching force is implemented like this: can record a pre-fastening moment with tension indicating wrench or with common wrench by lever principle on the square tenon of worm screw one end, can calculate the Mmin value by formula (3).The revolution that continues rotary worm behind pretension can be calculated by formula (4), need not measure drive torque again, only needs to turn to the n value with spanner.After stretch-draw is intact, use fixedly worm screw of end cap (14).

For large-tonnage, the bridging crane main beam of large span adopts this Zhuan Zhi also can close coupling by many covering devices Zu, but Zhang must carry out when drawing simultaneously, and makes as far as possible the moment Xiang that applies etc., and stretching force that Yi exempts from each cover differs the addition bend of Yin beam. Can also Yi the tight device Yu of cover Zhang overlap equalizer pulley Zu more and close use, the big stretching force of Zeng.

Claims

1, a kind of box steel beam that is used for, prestressed takeup especially for bridging crane main beam, feature of the present invention is the bottom, two ends that tensioner and equalizer pulley are contained in beam respectively, in the tensioner, be contained on the worm-wheel shaft (5) on the housing (7) worm gear (1) is housed, this worm gear is meshed with worm screw (13) on being contained in housing (7), in the equalizer pulley, the pulley (18,20) that is contained on the clamping plate (19) can rotate around bearing pin (22), and steel rope (10) is wound on the worm gear (1) by garden pipe (17) and the pulley (18,20) of beam bottom.

2, device according to claim 1 is characterized in that having several grooves on the both sides shoulder of described worm gear (1), and the groove of both sides is symmetrically distributed and quantity equates, communicates with the exit skirt of opening at two shoulder end faces (9) respectively.

3, device according to claim 1, it is characterized in that on the described worm-wheel shaft (5) bearing being housed, this bearing is subjected to the groove on the end face of axial force one side by worm gear, steel ball (2), and bearing inner ring (3) is formed, and an end of worm-wheel shaft is equipped with a baffle plate (8), and the other end is drilled with an oil hole.

4, device according to claim 1 is characterized in that described pulley (18,20) is installed in the groove of clamping plate (19), and is subjected to force direction to take turns the ascending arrangement in footpath by it at steel rope (10).

5, device according to claim 1 is characterized in that two of steel rope (10) is wound on respectively on the symmetrical channels of worm gear (1) shoulder, and is fixed on exit skirt (9) lining.