JPS6030845B2 - Improvement of split nuts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element for use as a split nut in which the element of the nut cooperates with a retaining structure to form a stud bolt or a nut threadedly engaged with a bolt.

Conventional nuts have various usage limitations, such as requiring the nut to be screwed into a shield bolt or the entire exposed length of the bolt, making it difficult to remove the nut after a period of use. This restriction also includes things that are difficult or impossible to remove.

A serious problem arises especially when used in many industrial fields that experience harsh corrosive conditions. Even if you try to remove a corroded nut after several months of sewing, there are times when you cannot unscrew it and have to use a cutting tool. Split nuts have been devised in the past to make it easier to install and remove nuts, but conventional nuts generally have complicated designs and are expensive to manufacture, and installation is expensive in terms of labor and time. there were. Prior art split nuts often relied on locking devices to hold the nut pieces together, and generally required a pair of cooperating disparate pieces. U.S. Pat. No. 3,797,336 discloses a split nut device in which a groove is provided around a nut for fastening such a piece to a bolt, and a clip holding the peripheral surface is fitted into the groove.

However, this device is complex and expensive, requires special tools, and makes it impossible to fit nuts in areas that are difficult to reach. However, despite this clear need for effective, simple, and inexpensive split nut layering, the prior art has failed to meet this need. The present invention, together with improvements over the prior art, seeks to provide a device which reliably facilitates completely accurate installation of a split nut without requiring the user to take great care in using the nut. The present invention seeks to provide a split nut element extending approximately 18 distances about the axis of the split nut formed from two nut elements.

This axis coincides with the axis of the threaded bolt that attaches the split nut. The nut element has an internally threaded surface that engages with the bolt;
an outer circumferential surface, a first end surface and a second end surface at the axial ends of the nut element, and a first end surface extending between the threaded surface and the outer circumferential surface;
It has a side surface and a second side surface. The nut element is characterized in that it is provided with a locating device on at least one of said lateral sides, said locating device being symmetrically offset on opposite sides of a central plane passing through the nut element at right angles to the axis of said split nut. a protrusion provided and a recess corresponding to the protrusion; the protrusion and the recess engage each other with the recess and the protrusion of an upside-down substantially identical element to form a split nut; belongs to. Interengaging positioning devices limit relative movement of both nut elements in the ball direction. The threading of the inner surface of the nut cooperates with the threading of an inverted, substantially identical nut element to provide thread progression from one end of the split nut to the other, such that the first and second end faces are such that either end face is connected to the washer or workpiece. It is chamfered to engage within a corresponding recess to vertically mount the nut element around the bolt. In at least a preferred embodiment of the invention, the protrusion and the recess are mutually complementary and symmetrically staggered on opposite sides of said central plane, and the screw is provided with a protruding side surface of the nut element. 1800 diametrically opposed to each other about the axis, the central plane intersects the thread valley on one side of the nut element and the thread crest on the pond side, i.e. each side lies on the plane of the crack of the split nut. It's made the way it is.

The second side also has a positioning device that may be the same as or different from the positioning device of the first side.

However, this is not necessary and the second side surface may be completely flat. In at least some applications, this may be advantageous as it facilitates mutual orientation of the pair of nut elements by touch or sight.
More generally, however, the present invention provides an important advantage of a simple, inexpensive, and easy to manufacture split nut element that is easily assembled with identical split nut elements to ensure accurate alignment. can provide benefits. moreover,
If a flat surface for a spanner is provided on the circumference, a conventional spanner can be used to tighten the split nut. The nut will tighten completely by turning it a fraction of a turn.

This is particularly important where there is limited access to the nut, and also ensures ease of removal in highly corroded areas. Preferably, the sides are slightly set back from the true axial plane of the split nut so that a small clearance allows the nut element to be tightened around the bolt during use.

Another feature is that the chamfered end surface lies on a conical surface.

Although a spherical surface for chamfering can be used in practice, the angle of the conical surface to the axis of the split nut should preferably be between 300 and 75.
It is preferable to adopt a conical chamfer within the range of 0. The most preferred angle is about 60 degrees, because this allows the nut to be tightened with a small amount of rotation, and a strong structure can be created with a nut of standard height. Furthermore, over-deep counterbore of the washer or workpiece is avoided. The split nut of the present invention can be manufactured inexpensively and with small tolerances using known manufacturing techniques.

Furthermore, the installation and removal of the nut is quick and easy, with a pair of nut elements being slid into the counterbore of a workpiece or washer and tightened in perhaps only a fraction of a revolution. This design ensures quick and accurate assembly and axial alignment of the nut elements, eliminating the risk of axial displacement of a portion of the thread of one of the nut elements. Complex engagement devices are eliminated and the severe practical disadvantages of providing clockwise and counterclockwise elements for split nuts are avoided. Although it is preferred that the sides of the nut extend in a plane parallel to the rattan of the nut element, this is not a necessary condition and the planes may be at a small angle, such as 10 degrees, to the axis.

Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG.

1 to 3, the nut element 1 comprises a threaded inner surface 2, a semi-hexagonal outer surface 2a, a first end surface 3, a second end surface 4, and side surfaces 5 and 6.

Each of the end faces 3 and 4 is approximately 60o relative to the axis of the nut element.
It has a conical chamfered surface 7 at an angle of . In this embodiment, the positioning device on the side is provided with a protruding rectangular block 8 and a rectangular recess 9 into which the block 8 is slid, the recess being perpendicular to the axis of the nut element. are arranged at corresponding positions on opposite sides of the central plane A-A. The nut element has sides exactly 18 mm around the axis.
00, the center plane A-A passes through the center of the crest of the thread on one side of the nut element and passes through the trough of the thread on the other side. is configured to intersect the axial plane along a line passing through the center of the axis. The screw thread has a single ridge indicated by the reference numeral 10. The recessed portion 9 is, for example, approximately 1/4 of the length of the side surfaces 5 and 6 in all directions, as shown in the figure, and the flock 8 has a shorter axial length than this.Therefore, when the two nut elements 1,1 are placed opposite, they have side faces 5,
6. However, when they are engaged with the threads of the bolt 13, the end faces 3, 4 of the nut elements are aligned with each other. For this reason, the difference between the axial length of the concave portion 9 and the axial length of the block 8 is set to be less than the thread pitch. To assemble the split nut, take two identical elements and invert one element onto the other so that the block 8 on the side 6 of one element engages in the recess 9 on the side 6 of the other element. match.

Similar engagement occurs on the other side as well. This arrangement limits relative movement in the axial direction and perpendicular to the axis of the nut and ensures accurate inversion. The workpiece must be provided with a conical counterbore corresponding to the chamfered surface 7, or alternatively a washer provided with such a counterbore must be mounted on the workpiece. FIG. 4 shows the latter example, which includes a relatively thick washer 12 for receiving a split nut consisting of nut elements IA and IB. FIG. 4 also shows another optional feature, namely the use of a generally annular strong spring clip 16.

Although the face end of the clip is not shown, it is preferable that the opposing end face be concave so that it can be engaged with a scissor-like tool for pushing the clip open for attachment and detachment. This clip 16 greatly increases the resistance to rotation of the split nut when tightening it. Conveniently, the nut is formed by a sintering process.

This is because such powder metallurgy technology allows high precision to be achieved and is convenient. Apart from being easy to remove even in the case of severe corrosion, the nut of the invention can be operated by simply sliding the nut element into a conical counterbore so that it approximates the position it will occupy when tightened. Can be installed quickly.

It has been reported that the manufacturing cost of the nut is only about 1'4 of the typical labor cost of an installation involving a conventional nut. The present invention is very quick to install, especially in situations where access and full operation are difficult, and provides significant overall cost savings. Another significant advantage achieved with the practice of the present invention is a mechanically superior product compared to conventional nuts, with much better load distribution on the screw.

For bolted nuts, most of the load is carried around the first round of the threads closer to the workpiece, and generally speaking, the pitch of the bolt threads increases with tension and the pitch of the nut threads decreases with compression. It is considered. Additionally, the threaded wedge causes the nut to bulge away from the bolt, effectively reducing the pitch of the nut during the first few turns close to the workpiece.
In the present invention, in contrast, a conical workpiece or washer secures the nut element to the bolt. It is believed that as the nut element rotates, the load is supported more evenly.
Although this explanation of the theory of the advantages of the present invention is purely a possible explanation, applicants do not intend to be bound by the accuracy or completeness of this theory.

[Brief explanation of the drawing]

Fig. 1 is a front view of the split nut element, Fig. 2 is a plan view of the nut element, Fig. 3 is a side view of the nut element, and Fig. 4 is an axial sectional view of the structure consisting of the split nut, washer, and bolt. It is. In the figure, symbols IA and IB are nut elements, 3
4 is a first end face of the nut element, 4 is a second end face, 5 and 6 are side faces, 7 is a chamfered face, 8 is a projection, 9 is a recessed part, 12 is a washer, and 16 is a spring ring. Fig. 1. F'9.3. Fi9.2, Figmu.

Claims (1)

Claims: 1 (a) If a split nut element is used, the threaded bolt with which the split nut engages extends approximately 180° about a center coincident with the axis of the threaded bolt with which it engages, and is shaped (b) extends in the axial direction between the first end surface and the second end surface of the element; (c) has an outer circumferential surface;
(d) a female threaded surface for threaded engagement with a bolt; (e) a first side surface and a second side surface each extending between an inner surface and an outer surface; at least one of the surfaces 5, 6; are provided with positioning devices 8, 9, which locate the central plane A-A passing through the nut element at right angles to said axis.
It consists of a protrusion 8 and a corresponding recess 9 provided substantially symmetrically on opposite sides of the nut element, the protrusion and the recess respectively being substantially identical to the recess and the protrusion of the inverted nut element. can be engaged to form a split nut and limit relative axial movement of both nut elements, the internal thread being such that a line intersecting the half nut at the intersection of the central plane and the plane of the split. said inner surface being threaded to correspond to the thread passing approximately through the center of the thread trough on one side of the nut element and approximately through the crest of the thread on the other side; said first and second end surfaces 3; , 4 are used with substantially identical elements to form a split nut, with either end face being chamfered 7 to engage within a corresponding recess in the washer or workpiece 12 to tighten the nut onto the bolt. Elements that form. 2. The device according to claim 1, characterized in that the positioning devices 8, 9 consist of a protrusion 8 and a recess 9 of the same shape and position provided on each side of the side surfaces 5, 6. element. 3. In the item according to claim 1 or 2, each protrusion 8 is a rectangular block provided close to the outer edge of the side surface, and each recess 9 has a dimension larger than the pitch of the screw. approximately 1/4 of the axial length of the side surface
An element that is a rectangular recess that reaches . 4. In the product according to any one of claims 1 to 3, the chamfered surface 7 of each end face 3, 4 is a conical surface whose axis coincides with the axis of the element. An element characterized by 5. Element according to claim 4, wherein the conical shape faces the axis of the nut element at an angle of 30° to 75°. 6. Element according to claim 5, characterized in that said angle is approximately 60°. 7. Element according to any one of claims 1 to 6, wherein the end faces are spaced apart by an amount slightly less than 180° about the axis of the nut element. 8. Each of the nut elements 1A and 1B corresponds to any one of claims 1 to 7, and the washer 12 has an angle of the chamfered surface 7 provided on the end faces 3, 4 of the nut element. A split nut unit consisting of a washer and two substantially identical elements characterized by being counterbored in a conical shape at the same angle. 9. The splitter according to claim 8, characterized in that a substantially annular threaded ring 16 is provided on the circumferential surface of the nut elements 1A and 1B, arranged to fit in a fastening relationship. Nut unit.