GB2565635A

GB2565635A - A manufacturing method of an attraction plate for electromagnetic door locks

Info

Publication number: GB2565635A
Application number: GB1810457.0A
Authority: GB
Inventors: Liao Yi-Fan
Original assignee: Yi Fan Liao
Current assignee: Yi Fan Liao
Priority date: 2017-06-29
Filing date: 2018-06-26
Publication date: 2019-02-20
Also published as: CN207469968U; FR3068379A3; GB201810457D0; FR3068379B3

Abstract

An attraction plate assembly 30 for an electromagnetic door lock has an attraction plate on a mounted body with a positioning hole 35 41 at the centre thereof. The attraction plate has an arch portion 32 at the centre which has a height inversely proportional to the thickness of the plate. The plate has convex curved underside surface which extends from the centre arch to free ends 34. A single bolt 50 secures the attraction plate to the mounted body with the ends of the plate being free and acts as a fulcrum allowing both free ends to move under the attraction of the electromagnet (phantom lines Fig 6). The thickness of the attraction plate is 10-16mm and preferably the height of the arch portion is 0.04-0.27mm. A pad 42 may be located under the plate in the arch region. The shape of the plate accounts for changes in the magnetic flux density which is stronger at the end regions of the plate and weaker in the middle region.

Description

TITLE: A MANUFACTURING METHOD OF AN ATTRACTION

PLATE FOR ELECTROMAGNETIC DOOR LOCKS

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The invention relates to an attraction plate for electromagnetic door locks, particularly to one that has a thickness of an attraction plate being inversely proportional to a height of an arch portion and the thickness is manufactured according to a pre-determined convex-curve surface of the attraction plate.

2. Description of the Related Art:

In the access control monitoring system, the use of an electromagnetic door lock has been very popular. The electromagnetic door lock provides an electric magnet mounted on a door frame and an attraction plate mounted on a corresponding position of a door plate. When the electric magnet is energized to produce electromagnetic attraction and attract the attraction plate, the electromagnetic door lock is turned into a locked status. When the electric magnet is de-energized and the attraction plate detaches from the electric magnet, the electromagnetic door lock is then turned into an unlocked status.

A traditional attraction plate comprises an attraction surface in a flat shape, and one or two positioning holes. The attraction plate is fixed on a mounted body by a screw and other related accessories. Basically, the mounted body can be set to any shape or the door plate can be directly mounted as a mounted body to fix the attraction plate by the screw and other related accessories. No matter what the shape of the mounted body is, the method of combining the mounted body and attraction plate is the same, and the attraction surface is a flat surface. This kind of structure of the attraction surface has been used for many years. After continuous research, the inventor found out that after the electric magnet is energized, the magnetic flux density is strong in the region of both ends and weak in the middle region. Thus, when the door plate is pulled, the action force is focused on the screw in the middle, and the electric plate is pulled by the screw. Meanwhile, the middle region of the electric plate is curved and deformed, and the curvature and deformation will affect the attraction effect on both sides of the electric plate. That is, when the region of the electric plate is curved and deformed, the attraction surface will become departed from the electric magnet. The experimental result shows that when the electric magnet is subjected to 500mA current and 12V voltage, the electric magnet with strength of 1200 pounds is easily pulled away from the attraction plate as the tension value is between 1000 to 1150 pounds. Therefore, to increase the attraction force of the attraction plate of the conventional electromagnetic door lock, the current of the electric magnet or the attraction area of the electric magnet and attraction plate should be increased, resulting in a waste of energy or increasing the materials and transportation costs. Accordingly, there is room for improvement in the structure of a conventional attraction plate.

FIG. 1 illustrates an armature for electromagnetic lock 10 disclosed in U.S. Patent No. 4,957,316. It has an attraction plate 11 arranged in a curved surface 12 bowing between 0.004-0.005inches for the purpose of increasing the tensile values. However, such arrangement is not applicable to the attraction plate 11 with different thickness; even worse, it might cause opposite effects.

Moreover, the thickness of the attraction plate 11 has something to do with a height of an arc portion. If the height of the arc portion cannot adjust correspondingly with the thickness of the attraction plate 11, the tensile value cannot be increased as expected. Nonetheless, in U.S. Patent No. 4,957,316 there is no disclosure or specific illustration of numbers of the thickness of the attraction plate 11 and its corresponding height of the arc portion.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an attraction plate for electromagnetic door locks that is able to increase a tensile value of a door lock by at least 10%, in order to achieve purposes of energy-saving and ensuring safety.

To achieve the object mentioned above, the present invention comprises an electric magnet in a long shape; a mounted body disposed at a corresponding side to the electric magnet with a positioning hole arranged in the middle thereof; an attraction plate with a thickness between 10-16mm and a length in correspondence to the length of the electric magnet, said attraction plate including an attraction surface at a side facing the electric magnet; a thickness of the attraction plate selected to determine a height of an arch portion arranged at the center on the attraction surface, the thickness of the attraction plate being inversely proportional to the height of the arch portion; manufacturing the attraction plate according to pre-determined numbers of thickness and height, the attraction plate having two corresponding convex-curve surfaces extending from the arch portion to both ends of the attraction plate, defining the arch portion a higher central region than both ends of the attraction plate; a spot-faced hole correspondingly arranged to the positioning hole of the attraction plate; and a bolt engaged through the spot-faced hole from the attraction surface and fixed in the positioning hole for setting a middle point on a bottom surface of the attraction plate as the fulcrum and defining both ends of the attraction plate as free ends when the attraction plate is mounted on the mounted body.

With structures disclosed above, the present invention is able to increase the tensile value of the electric magnet for door locks by more than 10 % without altering or changing the electric currents of the electric magnet thereof or the attraction area of the attraction plate. Such design also has features of energy-saving and efficient functioning for better safety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a mounted body of a conventional electromagnetic door lock;

FIG. 2 is a side elevation view of an attraction plate of the present invention;

FIG. 3 is an exploded view of the present invention in a preferred embodiment;

FIG. 4 is a perspective view of the present invention in a preferred embodiment;

FIG. 5 is a sectional view of the present invention in a preferred embodiment;

FIG. 6 is a sectional view of the present invention in a preferred embodiment illustrating a magnet thereof in attraction with an attraction plate thereof;

FIG. 7A is a sectional view of an attraction plate structure in the present invention;

FIG. 7B is a partially enlarged view of area 7B in FIG. 7A;

FIG. 8A is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 10mm;

FIG. 8B is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 11mm;

FIG. 8C is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 12mm;

FIG. 8D is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 13 mm;

FIG. 8E is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 14mm;

FIG. 8F is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 15mm;

FIG. 8G is a spline chart illustrating a relationship between a height of the arch portion thereof and a thickness of the attraction plate with the attraction plate being 16mm; and

FIG. 9 is a chart concluding a preferable range of a height of the arch portion thereof with a thickness of the attraction plate ranging from 10mm to

16mm in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 2-9, in a preferred embodiment, the present invention comprises an electric magnet 20, a mounted body 40, an attraction plate 30 and a bolt 50.

The electric magnet 20 is arranged in a long shape to be fixed to a door fame 15; the electric magnet 20 is designed according to the prior art and is not the main feature of the present invention. The mounted body 40 is disposed at a corresponding side to the electric magnet 20 with a positioning hole 41 arranged in the middle thereof. The mounted body 40 can be in different design to be installed on a door plate 14. In this embodiment, it can be a box-shaped body, a U-shaped body, a L-shaped body, a flat body; or it can be made in one piece together with the door plate 14 for attraction engagement.

The attraction plate 30 has a thickness T between 10-16mm and a length in correspondence to the length of the electric magnet 20. The attraction plate 30 also has an attraction surface 31 at a side facing the electric magnet 20. The thickness T of the attraction plate 30 is selected to determine a height h of an arch portion 32 arranged at the center on the attraction surface 31. The thickness T of the attraction plate 30 is inversely proportional to the height h of the arch portion 32. With the thickness T of the attraction plate 30 being between 10-16mm, the height h is arranged between 0.04-0.27mm.

The attraction plate 30 is manufactured according to pre-determined numbers of thickness T and height Ii. The attraction plate 30 further has two corresponding convex-curve surfaces 33 extending from the arch portion 32 to both ends 34, defining the arch portion 32 a higher central region than both ends 34. The convex-curve surfaces 33 are higher than a bottom plane L. The bottom plane L is a virtual plane formed along the lowest point of the ends 34, and the height h of the arch portion 32 is the height from the lower bottom from the center of the arch portion 32 to the bottom plane L. With the inversely proportional relationship, the thinner the attraction plate 30 is within the 10-16mm, the curve of the convex-curve surfaces 33 has a higher convex. The convex-curve surfaces 33 can be made by bending, stamping, shaping, or all known manufacturing method.

A spot-faced hole 35 is arranged correspondingly to the positioning hole 41 of the attraction plate 30, and a pad 42 is arranged between the attraction plate 30 and the mounted body 40.

The bolt 50 is engaged through the spot-faced hole 35 from the attraction surface 31 and fixed in the positioning hole 41 for setting a middle point on a bottom surface of the attraction plate 30 as the fulcrum and defining both ends of the attraction plate 30 as free ends when the attraction plate 30 is mounted on the mounted body 40.

Thereby when the attraction plate 30 contacts the electric magnet 20, the attraction plate 30 with internal stress would be attracted, deformed and attached to the electric magnet 20 as shown in FIG. 6.

To further illustrate the essential relationship between the thickness T of the attraction plate 30 and the height h of the arch portion 32 thereof for better tensile values, an experiment is conducted and concluded in a table below. In the table, the thickness T has a length of 185mm, a width of 60mm and different thickness T of 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, and

16mm. The voltage is 12V and the electric magnet 20 has a 500mA electric current passing through.

Tensile values with different thickness (T) and height (h)
Vfhickncss (T) Height (h)\.	10mm	11mm	12mm	13mm	14mm	15mm	16mm
0.00	976	1060	1080	1190	1213	1245	1295
0.01	980	1085	1142	1252	1235	1240	1310
0.02	1000	1102	1150	1252	1245	1248	1347
0.03	1010	1113	1169	1257	1252	1256	1353
0.04	1044	1143	1201	1268	1274	1278	1394
0.05	1060	1158	1216	1300	1290	1301	1392
0.06	1065	1181	1222	1310	1304	1387	1381
0.07	1103	1188	1239	1327	1320	1385	1252
0.08	1117	1216	1269	1331	1376	1335	1248
0.09	1138	1226	1294	1335	1380	1215	1236
0.10	1150	1227	1304	1359	1330	1145	1115
0.11	1168	1250	1308	1364	1217	1110	1041
0.12	1184	1262	1315	1346	1187	1026	961
0.13	1197	1281	1330	1212	1145	943
0.14	1212	1290	1337	1152	1064
0.15	1216	1298	1347	1105	937
0.16	1233	1299	1358	1035

0.17	1263	1314	1325	953
0.18	1276	1325	1154	938
0.19	1279	1343	1011
0.20	1281	1345	903
0.21	1285	1348
0.22	1303	1313
0.23	1318	1265
0.24	1319	1116
0.25	1324	964
0.26	1344
0.27	1323
0.28	1270
0.29	1070
0.30	916

From the numbers we can learn that the tensile values have different results with different thickness T and height h. However, it can be further concluded as following with reference to FIGS. 8A to 8G.

The arch portion 32 has a height h between 0.22-0.27mm when the 5 attraction plate 30 has a thickness T of 10mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.17-0.22mm when the attraction plate 30 has a thickness T of 11mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.12-0.17mm when the attraction plate 30 has a thickness T of 12mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.10-0.12mm when the attraction plate 30 has a thickness T of 13mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.08-0.10mm when the attraction plate 30 has a thickness T of 14mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.06-0.08mm when the attraction plate 30 has a thickness T of 15mm to obtain a preferable range of strong tensile values.

The arch portion 32 has a height h between 0.04-0.06mm when the attraction plate 30 has a thickness T of 16mm to obtain a preferable range of strong tensile values.

Although numbers of the tensile values would be different due to different sizes of the attraction plate 30, the increase percentages and curves of spline charts would still remain in the same tendency since attraction plates in the markets usually have a length ranging from 180mm to 200mm. FIG. 9 is a further conclusion from FIGS. 8A to 8G, illustrating the preferable ranges of heights h of the arch portion 32 with the thickness T of the attraction plate 30 ranging from 10-16mm.

In conclusion, the present invention has the attraction plate 30 being able to increase at least 10% of tensile values with the same number of electric currents passing through the electric magnet 20 by the specific numbers obtained from experiments, so as to be applied to door locks with better safety and energy-saving features.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.

Accordingly, the invention is not to be limited except as by the appended claims.

Claims

What Is Claimed Is:

1. An attraction plate for electromagnetic door locks, comprising:

an electric magnet in a long shape;

a mounted body disposed at a corresponding side to the electric magnet with a positioning hole arranged in the middle thereof;

an attraction plate with a thickness between 10-16mm and a length in correspondence to the length of the electric magnet, said attraction plate including an attraction surface at a side facing the electric magnet; a thickness of the attraction plate selected to determine a height of an arch portion arranged at the center on the attraction surface, the thickness of the attraction plate being inversely proportional to the height of the arch portion;

manufacturing the attraction plate according to pre-determined numbers of thickness and height, the attraction plate having two corresponding convex-curve surfaces extending from the arch portion to both ends of the attraction plate, defining the arch portion a higher central region than both ends of the attraction plate; a spot-faced hole correspondingly arranged to the positioning hole of the attraction plate; and a bolt engaged through the spot-faced hole from the attraction surface and fixed in the positioning hole for setting a middle point on a bottom surface of the attraction plate as the fulcrum and defining both ends of the attraction plate as free ends when the attraction plate is mounted on the mounted body.

2. The attraction plate for electromagnetic door locks as claimed in claim 1, wherein the height of the arc portion is between 0.04-0.27mm and the arch portion has a height between 0.22-0.27mm when the attraction plate has a thickness of 10mm; the arch portion has a height between 0.17-0.22mm when the attraction plate has a thickness of 11mm; the arch portion has a height between 0.12-0.17mm when the attraction plate has a thickness of 12mm; the arch portion has a height between 0.10-0.12mm when the attraction plate has a thickness of 13mm; the arch portion has a height between 0.08-0.10mm when

5 the attraction plate has a thickness of 14mm; the arch portion has a height between 0.06-0.08mm when the attraction plate has a thickness of 15mm; and the arch portion has a height between 0.04-0.06mm when the attraction plate has a thickness of 16mm.

3. The method as claimed in claim 1, wherein the mounted body is a

10 box-shaped body, a U-shaped body, a L-shaped body, a flat body, or a door plate.

4. The method as claimed in claim 1, wherein the mounted body further has a pad disposed between the attraction plate and the mounted body.