GB2114262A - Chain link for safety chain - Google Patents
Chain link for safety chain Download PDFInfo
- Publication number
- GB2114262A GB2114262A GB08302754A GB8302754A GB2114262A GB 2114262 A GB2114262 A GB 2114262A GB 08302754 A GB08302754 A GB 08302754A GB 8302754 A GB8302754 A GB 8302754A GB 2114262 A GB2114262 A GB 2114262A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chain
- cross
- section
- link
- bead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
- F16G15/00—Chain couplings, Shackles; Chain joints; Chain links; Chain bushes
- F16G15/12—Chain links
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
- F16G13/00—Chains
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
- Steering Devices For Bicycles And Motorcycles (AREA)
- Tyre Moulding (AREA)
- Hand Tools For Fitting Together And Separating, Or Other Hand Tools (AREA)
Abstract
A link for a safety chain for example to secure a bicycle against theft, is made from a material having a rectilinear cross-section (F) e.g. in the form of a trapezium having longer and shorter sides (5,4) respectively at the inner and outer peripheries of the link. Alternatively the cross-section may be square or rectangular. Where the ends of the material used to form a link are welded together, a bead (6) is formed of angled section to keep a cutting tool away from the weld. The length of the opening in each link is less than 3 times the width (B) of the cross-section. There is strong resistance against cutting by shears, and against insertion of a lever. <IMAGE>
Description
SPECIFICATION
Chain link for safety chain
The invention relates to a chain link for safety chains.
"Safety chain" is generally to be understood to mean any device which is used as security against theft for example in order to connect a bicycle, moped or a light motor cycle to a fixed structure, to fasten a boat to a ring mounted on a jetty, or in order to fix the adjacent bars of a gate to each other, etc.
Open-link chains which have links with a round, generally circular cross-section are usually used for this purpose.
In order to prevent unauthorised removal of the item fastened by the chain, the chain must be capable of resisting the cutting action of common metal shears or small shears generally known as "bolt cutters" or other similar implements, since a potential thief is not or at least not generally in a position to have costly and heavy apparatus such as oxygen cylinders and the like with him. In addition it should also not be possible to attack the links of safety chains with metal saws or files.
For these reasons the links of conventional safety chains are at present subjected to surface heat treatment of the most varied type in order to improve as far as possible the resistance to repeated cutting or to the use of files or the like. However, as regards the action of suitable shears or the like, no entirely satisfactory results have been achieved until now.
With this as a starting point, the invention is directed to the provision of a link for safety chains which is particularly resistant to cutting strain caused by conventional commerciallyavailable shears.
This is achieved according to the invention by providing the continuous length of material with a rectilinear cross-section. The cross-section may be square, or rectangular with two parallel sides parallel to the longitudinal plane of symmetry of the link which is at right angles to the plane of the link itself.
However in a preferred embodiment of the chain link the cross section is constructed in the form of an equal-sided trapezium in which the two parallel sides are arranged parallel to the longitudinal plane of symmetry of the chain link which is at right angle to the plane determined by the chain link itself, and the smaller of the two parallel sides of the trapezium faces outwards.
In conventional chain links with their round cross-sections there is practically point contact between the cross-section and the blades of the shears as is shown in Fig. 1 of the drawings; the pressure exerted by the blades can cause such severe strain that a crack is easily produced in the surface of the chain link and the material yields immediately below
the surface. This initial fracture is transmitted
in successive waves to the centre of the cross
section as is shown in Fig. 2, and the waves
extend along the surfaces S which expand
increasingly until they lead to a final fracture
of the chain link.
When welding the ends of a length of
material to form a chain link it has not proved
possible always to maintain the material
strength at the join. The join is thus the
preferred point for attack and also the join is
generally at the centre of a long side of the
chain link.
In a chain link according to the invention
with such a join a particularly advantageous
embodiment consists of providing a bead
which extends over the upper, inner and
lower surface of the relevant long side and at
right angles thereto in the region of the weld
point and which (viewed in the longitudinal
direction of the bead) has a cross-section with
lateral surfaces converging steeply towards
the tip of the bead. This prevents a cutting
implement being used at the weld point on
the chain link since the steep slope of the side
walls of the bead causes the implement to
slide off laterally into the region in which the
cross-sections are made from the original ma
terial.The cross-section of the bead is prefera
bly constructed substantially in the form of a
triangle or a pyramid and it is also preferred
for the lateral surfaces of the bead to enclose
an acute angle; in this way the lateral deflec
tion effect for a cutting implement is particu
larly effective, although the angle should not
be too acute in order to ensure that it causes
a marked lateral deflection of the cutting
implement. it is also advantageous of the
bead to be made from material coming out of
the cross-sectional profile at the weld point,
and this can be achieved by constructing the
bead during the welding process from the
material coming out of the normal cross-sec
tional profile.
A further preferred embodiment of the
chain link according to the invention consists
of selecting the length of the opening in the
chain link so that it is less than (or at the most
equal to) 3 times the width of the cross
section of the side of the chain link; this
construction means that the available space is
such that the largest lever that can be intro
duced into the chain link opening has a cross
section which is less than the cross-section of the side of the chain link itself; as a result the
lever is more likely to break than the chain. If
a bead is also present the space is largely
filled by the projecting bead and only the tip
of a cutting implement can be used since
further projection of the cutting implement
would be impeded by the next link in the
chain which is at right angles to the link in
question.In order to make a cut here the
cutting implement must be used at an angle; anyone anyone using a cutting implement would then be forced to incline the longitudinal axis of the blade relative to the axis of the cross-section of the link, and as a result would have to cut through not a cross-section running at right angles to the axis of the edge but, depending upon the angle of inclination, a much larger cross-section. This effect can be particularly advantageously enhanced by a further preferred embodiment in which the width of the bead cross-section in the base region of the bead is greater than the greatest possible distance (viewed in the longitudinal direction of the chain link) between two chain links passed through the opening of the chain link with the same cross-section. This results in drastic lateral deflection of a cutting implement.
Thus, the chain link according to the invention provides a high degree of security against undesirable cutting or forcing of the chain links.
The invention may be carried into practice in various ways, and certain embodiments will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 shows a conventional chain link for a safety chain (in section) with a cutting implement applied to it;
Figure 2 shows the principal strain over the cross-section of the chain link according to
Fig. 1 at both points of contact with the cutting implement;
Figure 3 shows a chain link according to the invention (cut) with a cutting implement applied to it;
Figure 4 shows the principal strain in the chain link according to the Fig. 3 when a cutting implement is applied;
Figure 5 shows a perspective view of a section of a safety chain consisting of chain links according to the invention;;
Figure 6 shows a lateral view of the view according to Fig. 5 in which the two lateral chain links are cut in the central longitudinal plane;
Figure 7 shows a view of two interengaging chain links according to the invention with a bead with a cutting implement attacking one of them;
Figure 8 shows a side view of the view according to Fig. 7 in which the chain link to which the cutting implement is applied is cut in the central plane of the bead;
Figure 9 shows a perspective view of a section of a safety chain made from chain links with a bead according to the invention, and
Figure 10 shows a side view of the view according to Fig. 9 in which one chain link is cut in the vertical central plane in the longitudinal direction.
In the view according to Fig. 1 a chain link 1 of conventional type, i.e. with a circular cross-section F, is shown in section between the blades of a cutting implement 2 such as a bolt cutter or metal shears. Because of the almost punctiform contact between the cutting lines of the cutting implement 2 and the surface of the chain link 1, when the cutting implement 2 is closed, a very high specific pressure is produced which results in a path of line of force S inside the cross-section of the chain link 1 below the points of contact between the cutting implement 2 and the chain link 1 in a manner which is shown schematically in Fig. 2 by the path of lines of force S (concentration of lines of force).
By contrast Fig. 3 shows a chain link 1 according to the invention (also having a cutting implement 2 applied to it), but here the cross-section of the chain link 1 is constructed in the form of an equal-sided trapezium as can be seen immediately from Fig. 3.
Here the cutting implement 2 is no longer applied in a quasi-punctiform manner but along the whole side edges of the trapezium i.e. along the line of contact 3, so that the force exerted by the cutting implement 2 is distributed over a much greater contact surface than in the construction according to Fig.
1. As a result, it is much more difficult to cause the first crack in the outer surface of the chain link 1 and cause the subsequent yielding of the underlying layers. As in Fig. 2, in
Fig. 4, the path of lines of force S for the cross-section shape shown in Fig. 3 is shown inside the cross-section F of the chain link 1, and it is clearly visible that the distribution of strain in much more even and less concentrated there.
When reference is made to a "cross-section
F", of the chain links, this refers to the crosssectional shape which is obtained when one individual side of a chain link 1 is cut through when the cutting plane lies at right angles to the longitudinal axis (central axis) of the link shape formed by the chain link. This crosssection is referred to as "cross-section F" and this cross-sectional shape is present along the entire periphery of the chain link. The "crosssection" thus indicates the cross-sectional shape of the length of starting material from which the chain link was produced.
A section of a safety chain in which chain links 2 according to the invention interengage is shown in perspective view in Fig. 5. The cross-section F of these links 1 is in the form of an equal-sided trapezium, as can be seen from the cut link on the left in the sectional view in Fig. 5. The parallel surfaces 4 and 5 of the trapezium (cf. Fig. 4) are so arranged that the inner peripheral surface formed by the chain link and the other peripheral surface are parallel to each other and to the central longitudinal plane P which is at right angles to the central plane Q-Q determined by the chain link (Fig. 6). As can be seen from Figs.
3, 5, and 6, when a. cross-section of an equalsided trapezium is used the longer of the parallel sides namely the side 5 (Fig. 4) is used to form the inner peripheral surface of the chain link and the shorter of the parallel sides, namely the side 4 (cf. Fig. 4) is used to form the outer peripheral surface; this ensures that the upper and lower surface of the chain link formed by the inclined sides of the trapezium cross-section enclose between them an angle the apex of which lies outside the surface enclosed by the chain link, so that the aligned inclination of commercially available cutting implements is taken into account and, as Fig. 3 shows very well, an almost linear application of the cutters of such cutting implements 2 can be achieved when attempting to cut such chain links.Square crosssections F also provide a very good resistance against such cutting implements, although the trapezium shape gives even better results in many cases. In this way cutting of the chain is practically impossible. It has been shown that for cross-sections F of circular and trapezium shape to fracture the necessary cutting forces lie in a ratio of up to 1:10. The links 1 which are used with such cross-section are then produced with a relatively small length and width, as can be seen from the drawings, in order to prevent the introduction and turning of the cutting blades towards the edges of the cross-section F.As is again shown in Fig. 6, the position of the parallel sides 4 and 5 of the trapezium shaped cross-section F is chosen so that they come to lie parallel to the plane of symmetry P-P which extends in the longitudinal direction of the chain link and is aligned at right angles to the central plane
Q-Q formed by the chain link itself.
If chain links with a square cross-section F or with a rectangular cross-section F are used, then two parallel sides are aligned in the longitudinal direction parallel to the plane of symmetry P described in greater detail in Fig.
6, like the sides 4 and 5 in Fig. 6, whilst the other two parallel sides lie at right angles thereto.
Figs. 7 to 10 show chain links 1 according to the invention which are constructed with a square cross-section F. The welded seam which is produced during welding of the chain links is arranged (viewed in the longitudinal direction of the chain link 1) approximately in the centre of one side (at right angles to the longitudinal axis thereof). As can be seen particularly well in Fig. 7 or Fig. 9 or also in
Fig. 10, an additional shaping of the chain link can be provided at this weld point on this long side: care is taken during welding of the chain link 1 to see that during the welding process a bead 6 is formed from material coming out of the normal cross-sectional profile, runs at right angles to the longitudinal direction of the side in question on the surface thereof and extends at least over the upper, inner and lower surface of the relevant side of the chain link.In all cases care will be paid to ensuring a smooth surface on the outside of the chain link so that when the chain is used there is no undesirable projection to cause a risk of injury in handling the chain. This arrangement of the bead 6 is shown particularly clearly in the view according to Fig. 8 which shows the extent of the bead over the upper, inner and lower surface of the relevant cross-section. The bead 6 is shaped in such a way that its cross-section (viewed in the longitudinal direction of the bead) has lateral surfaces which converge upwards at an angle to the tip of the bead and a cross-section of the bead 6 in the form of triangle or a pyramid recommends itself as particularly advantageous (cf. Figs. 9 or 10).
If a cutting implement 2 is used to break such a chain link, as shown in Fig. 7, then the cutting surfaces of this cutting implement are deflected by the side walls of the bead 6 in such a way that cutting at the welding point itself is not possible. Since the weld point is a particularly favourable region for undesirable cutting, the arrangement of the bead 6 ensures that the cutting implement 2 slides off laterally into the region in which the cross-section is made from the original material which has been heat treated on its surface. Furthermore if the chain link only has a short width of opening (approximately 3 X L-cf.Fig. 10), then because of the space filled by the projecting bead 6 this means that only the tip of the blades of the bolt cutter can be placed on the cross-section to be cut (cf. the view according to Figs. 7 or 8) because otherwise they would be severely impeded by the next chain link lying adjacent thereto at right angles. If anyone attempted to apply the cutting implement 2 to the chain link 1 not with the tip but over a greater cutting line, then they would be forced to hold the axis of the cutting implement 2 inclined relative to the axis of the crosssection F, and this would result in a cutting cross-section which no longer ran at right angles to the axis of the edge but a much greater cross-section would have to be cut through depending upon the chosen angle of inclination, and this is also a hindrance (cf.
Fig. 10). There is also the additional advantage that even a lever which might be introduced in order to break the chain link 1 can only have a rectangular cross-section of the surface s.t'L2, which is a limiting condition in that such a lever is more likely to break than the chain link 1. If the width of the bead cross-section in the base region of the bead 6 is chosen so that it is greater than the greatest possible distance t (Fig. 10) (viewed in the longitudinal direction of the chain link) between two chain links passed through the opening of the chain link 1 with the same cross-section F, these being pushed apart until they come to rest on the closed chain link, then it is particularly reliably ensured that a cutting implement 2 is so drastically deflected by the bead 6 that it is reliably impeded by the side of the adjacent link. The distance of the tip of the bead on the inside of the link from the opposite side is indicated by "s" as can be seen in Fig. 10.
The bead arrangement according to the invention provides an increased resistance to undesirable cutting and it also reduces the likelihood of breaking such a chain link by the introduction of a lever. The chain link can be made from any suitable material, but preferably from drawn steel extrusions or wires.
Claims (11)
1. A chain having links made from a length of material with a rectilinear crosssection.
2. A chain as claimed in Claim 1, in which the cross-section has two parallel sides which are parallel to the plane of symmetry of the chain link which is at right angles to the length of the link and at right angles to the plane of the link itself.
3. A chain as claimed in Claim 1 or Claim 2, in which the cross-section is in the form of a symmetrical trapezium.
4. A chain as claimed in Claim 3 in which the shorter of the two parallel sides of the trapezium is on the outer periphery, and the longer side is on the inner periphery, of the chain link.
5. A chain as claimed in any of Claims 1-4, in which in the links the ends of the material are welded in the centre of the length of one long side, and in the region of the weld, a bead is provided which extends over the upper, inner and lower surface of the side of the link and has a cross-section with lateral surfaces converging at an angle towards the tip of the bead.
6. A chain as claimed in Claim 5 in which the cross-section of the bead is generally triangular or pyramid-shaped.
7. A chain as claimed in Claim 6b in which the sides of the bead meet in an acute angle.
8. A chain as claimed in any of Claims 5-7 in which the bead is made from material derived from the cross-sectional profile of the material at the weld.
9. A chain as claimed in any of Claims 1-8 in which the length of the opening in each chain link is less than, or equal to, three times the width of the cross-section of the material.
10. A chain as claimed in any of Claims 5-9 in which the width of the cross-section of the bead in the base region of the bead is greater than the greatest possible distance viewed in the longitudinal direction of the chain link, between the two adjacent chain links.
11. A link for a chain as claimed in any preceding claim.
1 2. A chain as claimed in any of Claims 1-10 used to secure an article against theft.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT03322/82A IT1157418B (en) | 1982-02-02 | 1982-02-02 | Link for bicycle lock chain |
IT03405/82A IT1156590B (en) | 1982-04-20 | 1982-04-20 | Link for safety chain |
DE8212524 | 1982-04-30 |
Publications (3)
Publication Number | Publication Date |
---|---|
GB8302754D0 GB8302754D0 (en) | 1983-03-02 |
GB2114262A true GB2114262A (en) | 1983-08-17 |
GB2114262B GB2114262B (en) | 1985-10-09 |
Family
ID=27207510
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08302754A Expired GB2114262B (en) | 1982-02-02 | 1983-02-01 | Chain link for safety chain |
Country Status (6)
Country | Link |
---|---|
ES (1) | ES270070Y (en) |
FR (1) | FR2520824A1 (en) |
GB (1) | GB2114262B (en) |
IE (1) | IE53705B1 (en) |
IL (1) | IL67790A0 (en) |
SE (1) | SE8300179L (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3520363A1 (en) * | 1985-06-07 | 1986-12-11 | Fa. August Thiele, 5860 Iserlohn | Securing chain, in particular for securing bicycles, motorcycles or the like |
DE29504080U1 (en) * | 1995-03-10 | 1996-07-11 | Neukirchen, Roland, 50733 Köln | Safety chain |
DE19608040A1 (en) * | 1996-03-02 | 1997-09-04 | Roland Neukirchen | Safety chain |
EP1243813A1 (en) * | 2001-03-22 | 2002-09-25 | Maggi Catene S.P.A. | Safety chain with enhanced section |
US7195116B2 (en) | 2004-09-10 | 2007-03-27 | J.D. Theile Gmbh & Co. Kg | Link chain |
CN102562947A (en) * | 2011-12-03 | 2012-07-11 | 江苏欧玛机械有限公司 | Novel round-link chain |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3622110C2 (en) * | 1986-07-02 | 1995-06-14 | Westfalia Becorit Ind Tech | Feed device for mining extraction machines with a rack chain |
-
1983
- 1983-01-14 SE SE8300179A patent/SE8300179L/en not_active Application Discontinuation
- 1983-01-28 IE IE160/83A patent/IE53705B1/en unknown
- 1983-01-28 ES ES1983270070U patent/ES270070Y/en not_active Expired
- 1983-01-31 IL IL67790A patent/IL67790A0/en unknown
- 1983-02-01 GB GB08302754A patent/GB2114262B/en not_active Expired
- 1983-02-02 FR FR8301613A patent/FR2520824A1/en active Granted
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3520363A1 (en) * | 1985-06-07 | 1986-12-11 | Fa. August Thiele, 5860 Iserlohn | Securing chain, in particular for securing bicycles, motorcycles or the like |
DE29504080U1 (en) * | 1995-03-10 | 1996-07-11 | Neukirchen, Roland, 50733 Köln | Safety chain |
DE19608040A1 (en) * | 1996-03-02 | 1997-09-04 | Roland Neukirchen | Safety chain |
EP1243813A1 (en) * | 2001-03-22 | 2002-09-25 | Maggi Catene S.P.A. | Safety chain with enhanced section |
US7195116B2 (en) | 2004-09-10 | 2007-03-27 | J.D. Theile Gmbh & Co. Kg | Link chain |
CN102562947A (en) * | 2011-12-03 | 2012-07-11 | 江苏欧玛机械有限公司 | Novel round-link chain |
Also Published As
Publication number | Publication date |
---|---|
SE8300179D0 (en) | 1983-01-14 |
ES270070U (en) | 1983-07-16 |
IL67790A0 (en) | 1983-05-15 |
FR2520824A1 (en) | 1983-08-05 |
IE830160L (en) | 1983-08-02 |
ES270070Y (en) | 1986-07-16 |
GB2114262B (en) | 1985-10-09 |
SE8300179L (en) | 1983-08-03 |
GB8302754D0 (en) | 1983-03-02 |
FR2520824B3 (en) | 1985-02-15 |
IE53705B1 (en) | 1989-01-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940201 |