US3835690A

US3835690A - Device for connecting metallic sleeves to finned reinforcing bars

Info

Publication number: US3835690A
Application number: US00192435A
Authority: US
Inventors: W Fastenau; F Leonhardt; V Hahn
Original assignee: Ed Zueblin AG
Current assignee: Ed Zueblin AG
Priority date: 1968-11-02
Filing date: 1971-10-26
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17

Abstract

Apparatus is disclosed for connecting sleeves to fin-equipped reinforcing bars for concrete, which bars consist of a material which is harder than the material of said sleeve. The sleeve is deformed by pressure in such a way that the fins of said reinforcing bar means press themselves into the sleeve and positively interlock therewith while the deformation of the sleeve is effected in sections over the length of the sleeve.

Description

United States Patent 11 1 Leonhardt et al.

[111 3,835,690 [451 Sept. 17, 1974 Filed:

DEVICE FOR CONNECTING METALLIC SLEEVES TO FINNED REINFORCING BARS Inventors: Fritz Leonhardt, Stuttgart; Volker Hahn, Leinfelden; Werner Fastenau, Esslingen-Rudern, all of Germany Ed. Zublin Aktiengesellschaft, Stuttgart, Germany Oct. 26, 1971 Appl. No.: 192,435

Related U.S. Application Data Division of Ser, No; 872,950, Oct. 31, 1969,

abandoned.

Assignee:

Foreign Application Priority Data Nov. 2, 1968 Germany 1806665 References Cited UNITED STATES PATENTS Scott 72/412 1,727,896 9/1929 Mraz 72/412 1,813,520 7/1931 White 72/415 2,202,125 5/1940 Temple 72/415 2,831,377 4/1958 Harvey 72/453 2,940,497 6/1960 Herrstrum 1 72/453 2,941,430 6/1960 Klingler 72/453 3,263,465 8/1966 Way 72/412 3,326,029 6/1967 Portcr 72/45'1 Primary ExaminerCharles W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firm-Walter Becker [57] ABSTRACT Apparatus is disclosed for connecting sleeves to finequipped reinforcing bars for concrete, which bars consist of a material which is harder than the material of said sleeve. The sleeve is deformed by pressure in such a way that the tins of said reinforcing bar means press themselves into the sleeve and positively interlock therewith while the deformation of the sleeve is effected in sections over the length of the sleeve.

8 Claims, 15 Drawing Figures /mnm.s.-

PAIENIEBSEP 1 mm sum 1 u; 3

DEVICE FOR CONNECTING METALLIC SLEEVES TO FINNED REINFORCING BARS This is a divisional application of co-pending Ser. No. 872,950, Leonhardt et al., filed Oct. 31, 1969, now abandoned.

The present invention relates to a method of and device for connecting metallic sleeves to finned reinforcing bars. Such a method is employed, for instance, in

' order to interconnect reinforcing bars.

It is an object of the present invention to provide a method and device, as set forth above, which will make it possible to connect the sleeves safely and in a very simple manner to finned reinforcing bars without the exercise of relatively high forces.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 illustrates an axial section through a device according to the present invention. I

FIG. 2 represents a section taken along the line II-II of FIG. 1.

FIG. 3 illustrates the device according to FIG. 2, but with the press die in opened condition, i.e., prior to the pressing operation.

FIG. 4 illustrates a cross section through a sleeve connection according to the invention with the stress diagram pertaining thereto.

FIG. 5 is a cutout of a modification of a sleeve connection.

FIG. 6 is a portion of the sleeve connection as seen in longitudinal direction.

FIG. 7 illustrates the arrangement of the device according to FIGS. 1 3 for producing the sleeve connection of FIG. 6.

FIG. 8 represents an arrangement of the device subsequent to the arrangement of FIG. 7.

FIG. 9 is a cross section through a sleeve according to the invention.

FIG. 10 shows the sleeve of FIG. 9, but in reverse arrangement.

FIGS. 11 and 12 respectively illustrate two modified sleeves somewhat similar to those of FIGS. 9 and 10.

FIG. 13 illustrates a sleeve composed of one cylindrical member only.

FIGS. 14 and 15 respectively illustrate two further embodiments of sleeves for interconnecting steel inserts.

With the method according to the present invention for connecting metallic sleeves to finned reinforcing bars, the sleeve which consists of a softer material than the reinforcing bar is deformed by pressing while the fins or ribs of the reinforcing bar are pressed for positive engagement into the inner sides of the sleeve, the deformation of the sleeve being effected stepwise over sections of the length of the sleeve. By subdividing the deformation in timewise successive deforming phases, a relatively small force for deforming the sleeve will suffice so that it is possible to connect the sleeve also, for instance, on a building lot to the reinforcing bar or bars while using light devices. Expediently, the deformation on adjacent sections are effected successively while the deformation can be carried out in a simple manner from one end of the sleeve toward the other end. Furthermore, it is advantageous to carry out the deformation over sections of equal length so that a simple method or process is obtained.

For purposes of increasing the strength of the connection of the sleeve with the respective reinforcing bar, the deformationis effected substantially uniformly over the entire circumference of the sleeve. In this connection the deformation of the sleeve may be effected in at least two different radial directions, preferably offset to each other by In order to avoid a decrease of the fatigue strength of the sleeve connection in view of a too strong transverse pressure, it is expedient to press the sleeve along its intermediate range of its length at a greater force against the reinforcing rod than at least against one end. The pressing force decreases from the intermediate range of the sleeve expediently to the end thereof in a steady way while the end of the sleeve advantageously surrounds the reinforcing bar in a pressure-free manner. This may be realized in a simple manner by arranging the sleeve in the area of its end, prior to the deformation of the sleeve by preferably conically widening the sleeve opening, with a greater radial play than in the intermediate range of the sleeve. In this way also sharp inner edges of the sleeve within the area of its ends will be prevented from engaging the reinforcing bar or bars.

According to a further feature of the invention, with the deformation of a partial section of the length of the sleeve, the pressing force at the end of a partial section decreases preferably in a steady way so that at the merging area from the pressed to the unpressed portion of the sleeve no sharp edges but only a rounded portion will be formed.

A butt connection between finned reinforcing rods, which connection is effected in particular in conformity with the above mentioned method, is characterized primarily by a pressing sleeve which positively sur rounds both reinforcing bars and the material of which is softer than the material of the reinforcing rods so that in a simple manner a firm connection will be realized between the reinforcing bars.

For purposes of increasing the fatigue stress resistance of the sleeve connection, the sleeve opening is expediently at least toward one end of the sleeve preferably to both ends of the sleeve, conically widened.

A device for carrying out the method according to the present invention with two press dies adapted to be moved relative to each other and supported by a corresponding supporting means is characterized primarily by designing the press surfaces of the press dies shorter in axial direction than the sleeve, said press dies being widened at their ends. In view of this design, the device or the press may be relatively small and light so that they can easily be handled in a simple manner also on areas which are somewhat difficult to get at. The broadening at the ends of the die opening will assure that the sleeve at the end of each section or portion which has been pressed will not be damaged but will, through the intervention of a rounded portion, merge with the not pressed portion. Advantageously, the

broadening portions are formed by roundings.

An advantageous further development of the device according to the invention is characterized by a step control device which is connected to the holding means for stepwise feeding the device so that the feed of the press can be determined precisely and that in a simple manner a complete pressing of the sleeve over the entire length thereof will be assured. Expediently, the step control device has a gauge detachably connected to the reinforcing bar. This gauge is provided with recesses located one behind the other in the longitudinal direction of the reinforcing bar for a pawlmovably mounted on the supporting means. In this way the step control device can be aligned in a simple manner relative to the reinforcing bar. In order to be able to detach the gauge transverse to the reinforcing bar, the gauge is of a U- shaped cross section while expediently comprising a clamping screw or clamping wedge for connection to the reinforcing bar. The pawl may, in a simple manner, be joumalled on the holding means for pivoting about a pivot perpendicular to the central axis of the die opening.

Referring now to the drawings in detail, and FIGS. 1 3 thereof in particular, the arrangement shown therein comprises a tubular cylinder 1 which is closed at one end thereof by a, for instance, detachable cover 2 or by a one-piece end wall, while the other end is open. In the cylinder 1 there is reciprocably mounted a piston 3 which is provided with a corresponding seal 4. Piston 3 has that end face 5 thereof which faces away from the cover 2 provided with nonillustrated connecting means for detachable and exchangeable connection of a part 6 of a

press die

6, 7. The other part 7 of this die may to that end of the pipe which faces away from the cover 2 and forms the cylinder 1, be easily exchangeably connected by means of a bayonet joint 8. This end of the pipe which forms the cylinder 1 is provided with an axial slot 9, the width of which is greater than the diameter of the sleeve to be deformed while the height of the slot 9 equals at least the diameter of the sleeve 10 plus the height of the part 7 of the press die. At its rear side the piston 3 is provided with a recess 11, the bottom of which, has an eye 12. This eye 12 is located opposite an eye 13 on the inner side of the cover 2 while between the two eyes 12, 13 there is clamped a preloaded tension spring 14. In the cover 2 of the cylinder 1 there is furthermore provided a passage 16 which leads into the pressure chamber and is equipped with nonillustrated connecting means for connection to a pressure line.

With the embodiment illustrated in FIGS. 1 3 it is intended to connect the sleeve 10 which in its starting position is cylindrical to the two oppositely located ends of two finned reinforcing rods or bars 17, 18 in such a way that the two reinforcing rods or bars 17, 18 are firmly interconnected by the sleeve 10. The sleeve 10 which in its starting condition has an inner diameter which is greater than the outer diameter of the reinforcing

bars

17, 18, is to this end first placed upon the two ends of the reinforcing

bar

17, 18 in such a way that the two end faces thereof will be located directly adjacent to each other. Thereupon, the pressing device is, prior to the connection of the part 7 of the press die, slipped upon the sleeve in such a way that the sleeve 10 or the reinforcing

bars

17, 18 are located in the slot 9 of the pipe forming the cylinder 1 and that the press surface 19 of the pressing die portion 6 engages the circumference of the sleeve 10. Thereupon the press die part 7 may, by means of a bayonet joint 8, be connected to that end of the cylinder 1 forming a pipe which protrudes beyond the circumference of the sleeve 10. This connection will be so effected that the sleeve 10 is located between the die surfaces 19, 20 of the press die 6, 7, which surfaces form the die opening.

The length of the press surfaces 19, 20 of the press die 6, 7 is, when measuring in the longitudinal direction of the sleeve 10 or in axial direction of the opening of the die, shorter than the length of the sleeve 10. As a result thereof, the sleeve 10 has to be deformed stepwise over sections of its length while for purposes of deformation of each portion or section only a relatively low pressing force is required so that a weight saving light and space saving construction of the pressing device will be obtained.

For purposes of deforming a portion or section of the sleeve 10, a pressure medium such as oil under pressure is conveyed through the passage 16 into the pressure chamber 15 of the cylinder 1 so that the piston will be advanced against the thrust of spring 14, and the section or portion of the sleeve 10 will be pressed against the circumferential surface of the respective reinforcing

bar

17, 18. The ribs or fins 21 of the reinforcing bar are pressed into the inner surface 22 of the sleeve 10 which is of a softer material than the reinforcing

bars

17, 18 so that the sleeve 10 will be positively connected to the reinforcing

bars

17, 18. Following the deformation of the first section according to FIG. 1, the adja cent section is deformed whereupon that section will be deformed which is adjacent to the last mentioned section, etc. The corresponding successive positions of the press die 6, 7 are illustrated in FIG. 1 by 23a, 23b and 23c in dot-dash lines. The deformation of the sleeve 10 is thus effected in a continuous manner stepwise from one end of the sleeve toward the other end over equal lengths.

In order to be able to precisely fix the length of the individual sections, the device according to the present invention is provided with a step control mechanism. This step control mechanism 24 is equipped with a gauge 25 which is of a U-shaped cross section and the inner width of which is greater than the diameter of the reinforcing bars l7, 18 so that the gauge 25 is adapted in a transverse direction to the longitudinal direction of the reinforcing

bars

17, 18 to be placed upon one of the said reinforcing bars adjacent the sleeve 10. In a leg of the gauge 25 there is mounted, for instance, a clamping screw 26 with thread, which clamping screw forms a wing screw by means of which the gauge 25 can be firmly clamped against the respective reinforcing bar 17. At the circumference of the pipe which forms the cylinder 1 there is mounted on arm 27 which is pivotable about an axis 28 which is perpendicular to the piston axis and to the longitudinal axis of the reinforcing

bars

17, 18. The said arm 27 is at one end thereof equipped with a pawl 29 which is directed toward the central axis of the reinforcing

bars

17, 18. The pawl 29 has at the circumference of the gauge 25 associated therewith locking recesses 30 which, in the longitudinal direction of the gauge 25, are located one behind the other and which may be engaged by the locking bar 29. By moving the device along the sleeve 10 and by introducing the pawl 29 into the respective successive recesses 30, the length of the sections of the sleeve 10 which are to be successively deformed may be precisely ascertained.

As shown in FIG. 1, the press surfaces 19, 20 of the

die parts

6, 7 are at their ends respectively provided with rounded areas 31 in such a way that the die opening is rounded at its ends and widened in diameter. This brings about that after the deformation of one portion or section of the sleeve 10 there is formed a rounded transfer merging area 32 merging with the not-yet deformed portion of the sleeve so that damage to the sleeve 10 will be avoided at any rate.

By deforming the sleeve 10 in sections, it is also possible without difficulties to vary the pressing forces from section to section at which the sleeve 10 is pressed against the reinforcing

bars

17, 18. Expediently, according to FIG. 4, the sleeve 10 is within the range 33 of the center of the length of the sleeve pressed against the reinforcing

bars

17, 18 to a greater extent than in the areas 34 of its two ends. The corresponding pressing forces are illustrated in FIG. 4 by arrows of greater length. The length of the intermediate range 33 is so se lected that it will be effective at both ends of the reinforcing

bars

17, 18 over as great a length as possible. The pressing force in the ranges 34 may also decrease steadily toward the ends of the sleeve 10 while the merging of the pressing force between the

ranges

34 and 33 may likewise be steady or continuous.

Expediently, the inner surface of the sleeve 10 will at the ends thereof surround the reinforcing

bars

17, 18 in a pressure-free manner. This may be realized for instance by providing the opening of sleeve 10 at the ends thereof with rounded widening portions 35 according to FIG. 5 so that the sleeve 10 will at its ends not at all engage the reinforcing

bars

17, 18.

When deforming a section or portion of the sleeve 10 by means of a two-sectional press die 6, 7 there will in the dividing plane of this press die 6, 7 at the sleeve 10 sometimes be encountered a bead 36 of the material at two oppositely located sides of the sleeve 10 while the inner surface of sleeve 10 will likewise also in this range not engage the circumference of the reinforcing

bars

17, 18, but hollow spaces 37 will form. In order to avoid this form of the sleeve 10 in conformity with FIG. 6, the deformation of the sleeve is effected preferably in offset direction by 90 in conformity with FIGS. 7 and 8. The sleeve form according to FIG. 6 will be obtained after the deformation with the pressing device occupying the position shown in FIG. 7. After the dies 6, 7 have been opened, the pressing device is pivoted by 90 to a position shown in FIG. 8 so that now the sleeve 10 also within the area of the now formed beads 36 can be pressed firmly against the circumference of the reinforcing

bars

17, 18. In this connection it is possible to deform all of the sections of the length of sleeve 10 first at an angular position of the pressing device and subsequently in a reverse direction or in the same direction while changing the angular position of the pressing device to carry out once more the deformation in sections. However, it is also possible to employ the pressing device at each section directly one after the other in two different angular positions and only then to deform the next section of the sleeve 10.

FIG. 9 shows a sleeve according to the invention with a sleeve-like collar 101 which at one of its ends forms a trumpet-shaped widened anchor portion 102 which thus is widened from the collar 101. The sleeve is with its collar 101 slipped onto the end 103 of a steel insert 104 and is in radial direction (arrow 105) compressed inwardly against the steel insert 104 so that the sleeve will be firmly held. According to the specific illustrated embodiment, the steel insert 104 is formed by a concrete finned steel the circumference of which has fins or ribs 106. When compressing the collar 101 the ribs 106 are pressed into the inner surface of the sleeve 101 so that the latter following its compression will positively be arrested relative to the steel insert 104. The anchor part 102 merges by a ring portion 107 having a relatively slight curvature with the sleeve 101 while the free end of the ring member 107 has a bead 108 located in a radial plane.

According to the embodiment of FIG. 9, the anchor part 102 diverges in the direction of the end 103 of the steel insert 104 so that the steel insert 104 is anchored against pull in the direction of the arrow 109.

According to the embodiment illustrated in FIG. 10, the anchor part 102 which incidentally is of the same construction has its widened portion directed to the center of the steel insert 104 while the steel insert 104 also in this instance is arrested against pull in the direction of the arrow 109. The anchoring force of the anchor part 102 is, however, with the embodiment of FIG. 10, greater than with the embodiment of FIG. 9.

FIG. 1 1 illustrates that the anchor part 102a may also have its outer range curved to such an extent that the annular bead 108a is toward the rear at least partially directed in the direction of the sleeve 101.

According to the embodiment of FIG. 12, the sleeve 101b is designed so as to form a part which is separate from the anchor part 102b while the anchor part 102k expediently has its smaller end face 111 resting against an end face 110 of the sleeve 10lb.

If the adhesive or bond stresses are not too high, the sleeve may also be formed by a continuous cylindrical sleeve l01c which is likewise connected to the steel insert 104 in the form of a compressed sleeve. The circumferential surface 102a of the sleeve 1010 will in this instance by adhesive friction assure a sufficient anchoring which may furthermore be increased by an end face 102d of the sleeve 1010 which end face acts as abutment or anchoring surface.

According to the embodiment of FIG. 14 two slack steel inserts 104 have their directly adjacent ends 103 connected to each other by a common sleeve 112. Sleeve 1 12 is formed by means of two sleeves in conformity with FIGS. 9 and 10, the widened portions of which are directed towards each other while the collar 101 of each sleeve is connected to the end 103 of a steel insert 104. The anchor portions 102 which pertain to the two sleeves and are facing toward each other are placed against each other with their annular beads 108 and are connected to each other by a welding seam 113. In this way the steel inserts 104 are on one hand firmly connected to each other and on the other hand are anchored in the concrete.

FIG. 15 illustrates an embodiment which is similar to that of FIG. 13. Around the two ends 103 of two successive steel inserts 104 there is provided a common sleeve 101e which is substantially cylindrical and which in the form of a collar is in the manner described above connected to the steel inserts 104. This circumferential surface 102a as well as the end faces l02f of the sleeve 101e act as with the embodiment of FIG. 13 as anchoring means.

By means of the sleeve according to the invention, slack steel inserts can in a simple manner be ascertained and connected. In particular, the sleeve will, while requiring a minimum of space, assure a safe anchoring of slack steel inserts. Furthermore, the sleeve according to the invention is also suitable for interconnecting successive steel inserts arranged adjacent to each other, while the sleeve itself is simple in construction and inexpensive to produce.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings, but also comprises any modifications within the scope of the appended claims.

What we claim is:

1. An apparatus for joining sleeve means surrounding concrete reinforcing bar means to the latter, which includes: cylinder means having transverse passage means therethrough for receiving concrete reinforcing bar means and at least a portion of sleeve means surrounding the same, fluid operable piston means reciprocable in said cylinder means, first die means detachably connected to said piston means for exerting deforming pressure upon sleeve means to be connected to bar means introduced into said passage means, second die means detachably connected to said cylinder means and forming the counterpart to said first die means for deforming said sleeve means from the opposite side with regard to the portion to be deformed by said first die means, the front and rear edge portions of said first and second die means when looking in the longitudinal direction of said sleeve means flaring away from each other, and a stepping mechanism for stepwise advancing said bar means with said sleeve means.

2. An apparatus in combination according to claim 1, in which the flaring edge portions of die means are rounded.

3. An apparatus according to claim 1, in which said stepping mechanism comprises gauge means detachably connected to said bar means, said gauge means having recess means arranged one behind the other when looking in the direction of said bar means, and pawl means connected to said cylinder means for successively engaging said recess means.

4. An apparatus according to claim 3, in which said gauge means is of U-shaped cross section and comprises a clamping screw for detachable connection to said bar means.

5. An apparatus according to claim 3, in which said pawl means is pivotable about an axis extending in a direction transverse to the longitudinal axis of said pas sage means.

6. An apparatus according to claim 3, which includes spring means arranged within said cylinder means and continuously urging said piston means in the direction toward said passage means.

7. An apparatus in combination according to claim 1, in which said second die means is connected to said cylinder means by a bayonet joint.

8. An apparatus in combination according to claim 1, in which that portion of said cylinder means which has said second die means arranged therein is provided with axial slot means having a width in excess of the diameter of said sleeve means.

Claims

5. An apparatus according to claim 3, in which said pawl means is pivotable about an axis extending in a direction transverse to the longitudinal axis of said passage means.