US20220226879A1

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Info

Publication number: US20220226879A1
Application number: US17/536,912
Authority: US
Inventors: Mattias Andersson
Original assignee: Nord Lock AB
Current assignee: Nord Lock AB
Priority date: 2007-09-28
Filing date: 2021-11-29
Publication date: 2022-07-21
Also published as: EP2195129B1; US20100209214A1; US9636738B2; JP5475668B2; EP2195129A4; SE0702188L; CN101808761A; WO2009041906A1; TWI438349B; EP2801419A1; JP2010540253A; KR20100061508A; US20170259323A1; EP2195129A1; CN101808761B; PL2195129T3; KR101669182B1; TW200925447A; SE532183C2

Abstract

A method for the manufacturing of circular washers for locking from blanks, the washer having a central hole, a first side comprising a pattern of radially extending teeth and a second side comprising a pattern of radially extending cams.

The method is especially characterized in the steps of

- producing a washer blank having an annular shape;
- introducing the washer blank into a die assembly for forming a closed shaping space by a lower die portion, an opposing upper die portion, a central die portion and a support piece, the central die portion extending through a washer blank central hole;
- forming the blank to a washer by mutual movement of said lower and upper die portions;
- opening the closed shaping space to extract the formed washer.

The invention also relates to a device and a washer.

Description

1. BACKGROUND1.1 the Present Invention Relates to a Method for the Manufacturing of Washers for Locking

The present invention also relates to a device for the manufacturing of washers for locking.

Further, the invention relates to a washer for locking.

1.2 Prior Art

Washers as described above are previously known and provided for eg bolts or the corresponding fastening elements for locking purposes. In a locking system of this kind two washers are arranged in a pair, the cam pattern sides facing and engaging each other, the main cam surface inclination being larger than the pitch of the threads, which causes a positive and efficient locking of the fastening element.

According to what is previously known the washers are manufactured from a strip blank, which is fed to pass several stations, in which forming and/or punching is performed between upper and lower tools, the pattern of teeth being formed on and substantially covering the upper surface and the pattern of cams being formed on and substantially covering the lower surface of the washer.

This known technique is associated with several disadvantages and problems. Thus, there is a possibility that undesired displacements occur between the stations during feeding in the die arrangement, such displacements causing defect washers. Further, the total amount of blank material is quite high. Furthermore, there are restrictions related to the cam and teeth cover on each side of the washers, which decreases the possible load bearing surfaces. Also, the outer periphery is punched out and then receives a sharp edge, which causes problems in the further processing of the washer.

As described in Applicant's Swedish Patent Application No. 0501224-0 the outer periphery of the tooth pattern is deformed during the punching out of the washer. Therefore an edge zone free from pattern is formed, against which the punch rests during punching. This restricts the load transferring surface of the washer.

The object of present invention is to provide a solution to these problems associated with previously known technique.

SUMMARY OF THE INVENTION

The object of the present invention is obtained by a method, a device and a locking washer having the features specified in the claims.

Further advantages are obtained by what is specified in the respective dependent claims.

SHORT DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention will be had in view of the following description related to examples and preferred embodiments, when read in conjunction with the drawings, in which

FIGS. 1A-1E) schematically show axial cross-sectional views of a first embodiment of a die assembly according to the present invention in different process steps for forming a washer according to the present invention,

FIG. 2 schematically shows a first embodiment of a washer blank cut from a rolled strip,

FIG. 3 schematically shows a second embodiments of a washer blank formed from a wire having a circular cross-section,

FIG. 4 schematically shows a third embodiment of a washer blank formed from a wire having a square cross-section,

FIGS. 5A-5F schematically shows a washer produced according to the invention seen in perspective views, a front and a side view and a cross-sectional view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

InFIG. 1A a die assembly for the manufacturing of locking washers is designated by1. InFIGS. 5A to 5F, an example of awasher2 to be produced according to the invention is shown. These kind of locking washer comprises acentral hole3 for a bolt element to be locked by a washer arrangement and on one side4 a pattern of radially extendingteeth5 and on the other, the opposite, side6 a pattern of radially extendingcams7. The washer has an annular configuration and the respective patterns extend from theinner periphery8 to the outer periphery9. According to preferred embodiments the washer comprises a bevelledportion10 at the inner periphery, preferably on the side4 having the pattern of teeth, the bevelled portion being intended to adapt to a radius portion under the head of a bolt element.

The die assembly preferably has an axi-symmetric configuration coinciding with theaxial direction11 of a washer to be formed.

The die assembly comprises alower die portion12, anupper portion13 and acentral portion14. According to the embodiment shown the central die portion is fixed and the lower die portion and the upper die portion are mutually movable and arranged to form aclosed shaping space15 together with the central die portion and asupport piece1′ for providing a circumferentially running outer wall of said space, a washer blank2′, being intended to be formed to a washer in saidclosed shaping space15. InFIG. 1A the die assembly is open to receive a washer blank2′.

The lower die portion having received said blank, is movable towards the upper die portion, means, represented by an arrow F, being provided for forcing the lower die portion towards the upper die portion for forming said closed shaping space by the die portions by forcing the upper die portion against anend stop16 with the washer blank material applied in saidspace15, the lower die portion being arranged to be further forced towards the upper die portion for forming the washer blank to a washer as shown inFIG. 1C andFIG. 1D.

According to a preferred embodiment spring means17 are provided to provide a spring force F′, against which the upper die portion is displaced when forced towards the end stop, said spring force being provided for pushing out the formed washer when unloading the force F exerted by the lower die portion by retracting the lower die portion.

The spring force is acting on the upper die portion by egrods18 acting on anupper portion19 of the upper die portion, as schematically shown inFIG. 1D. Of course another guiding arrangement that therods18 may be imagined and for exerting a spring force F′.

According to preferred embodiments the die assembly is configured to form the tooth pattern and the cam pattern to extend from theinner periphery8 of the washer to the outer periphery9 of the washer. Preferably, thelower die portion12 is designed to form the pattern of cams and theupper die portion13 is designed to form the pattern of teeth.

According to preferred embodiments the die assembly, preferably by abevelled end portion20 of the central die portion as shown inFIG. 1E, is designed to form the washer with a bevelled configuration at the inner periphery to adapt to a radius under the head of a bolt intended to be locked by a washer arrangement, as described earlier, the bevelled configuration preferably being formed on the tooth pattern side4 of the washer.

According to one embodiment the blank2′ to be formed is cut from ametal strip2″. Such a blank is schematically shown inFIG. 1B.

According to another embodiment the blank2′ to be formed in the die assembly is formed from awire21 having a circular cross-section, as shown inFIG. 3.

According to a further embodiment the blank2′ to be formed in the die assembly is formed from awire21′ having a square cross-section, as shown inFIG. 4.

According to a still further embodiment an annular blank2′, as schematically shown inFIG. 1B-C, the die assembly is configured for cutting the blank from astrip2″ in the die assembly prior to forming the blank. In such a case the lower die portion is provided with a circumferentially runningedge portion22 and the die assembly is provided with asupport piece1′, which, apart from providing the circumferentially running wall of the closed shaping space, provides acutting edge24 for the blank cutting operation, the lower die portion working as a punch in this operation, the operation being schematically shown inFIG. 1C.

Embodiments may also be imagined according to which a blank in the form of a circular disc, ie without a central hole, is produced, the hole being punched out in the die assembly during forming of the washer, preferably by a central die portion.

In such a case the blank may be punched from a strip or being out, preferably by high velocity cutting, from a wire or a bar or a rod, high velocity cutting being performed with a very small play between the cutting dies and, thus produces a blank with a very accurate disc shape.

The method and function of the device according to the invention as well as the washer according to the invention should to a considerable and sufficient extent have been made clear from the description given above.

For the forming of a washer blank introduced in the die assembly a closed shaping space is formed by a lower die, an upper die, a central die and a support piece. Once the blank is properly introduced the total forming operation for the finished washer is performed in said closed space, which offers a number of advantages, including a proper forming of the two patterns with an extension from the inner periphery to the outer periphery.

In this way one blank or several blanks at the same time is/are formed in one single operation in a closed shaping space, In this way die setting is considerably simplified compared to a process in which a final product is formed in consecutive forming operations linked together by a blank strip, wherein the forming steps depend on each other and require an extremely accurate mutual setting, which requires continuous monitoring and maintenance.

According to preferred embodiments annular washer blanks are punched out/cut out from strips or sheets before being introduced into thedie assembly1. In this way the blanks may be punched out in a closely packed pattern, which saves the amount of blank raw material. These blanks may be fed to the die assembly in any convenient way prior to forming.

Other advantages are eg

- very accurate finished product dimensions;
- reduced material consumption since less space between the blanks when cut from a strip is necessary;
- less raw material storage since the number of band widths may be reduced;
- increased process security due to only a small number of settings are necessary;
- more efficient use of building area due to smaller press equipment;
- lower electrical power level necessary;
- smaller number of finished product defects offers higher productivity in glueing operations;
- thinner washers having a limited outer diameter may be produced due to accurate blank production.

Above examples and preferred embodiments have be given.

Of course, further embodiments as well as minor changes and additions may be imagined without departing from the basic inventive idea.

Thus, the washers are preferably made of steel, in particular low-alloy steel hardenable to a hardness of about or exceeding 465 HV.

According to preferred embodiments the washers are designed with an outer diameter for the washer to fit in a standard dimension counter bored hole having a flat bottom, the thickness of the washers being down to less than 1 mm, and according to preferred embodiments the die assembly is designed for forming such washers.

Thus, the invention should not be considered limited to the embodiments shown but can be varied within the scope of the attached claims.