CA1298716C

CA1298716C - Electric key

Info

Publication number: CA1298716C
Application number: CA000559585A
Authority: CA
Inventors: Shunsaku Nakauchi
Original assignee: Ryobi Ltd
Current assignee: Ryobi Ltd
Priority date: 1987-02-23
Filing date: 1988-02-23
Publication date: 1992-04-14
Anticipated expiration: 2009-04-14
Also published as: JPH0735706B2; AU603645B2; US4854619A; JPS63206581A; AU1207188A

Abstract

ABSTRACT OF THE DISCLOSURE
An electric key has a self-holding electromagnet for keeping attract a movable means holding a locking block in its nonconductive state and for releasing the movable means in its conductive state by a spring.
the movable means is returned by a hand-operation to a position where it is attracted on the electromagnet.
This results in saving of electric power.

Description

~LE~'l'RIC KEY

BA(,1CGl~t)11ND OF T~IE INV~NTION
T1~:is i11vent.ion relates to an electric key ~perated by electric signals, and more particularly, to an e:Lectric key which can be operated with a small a~l~ount ol clectric power.
In a co1~ventional electric key operated by e:Lectri~ signals, ~ locking and unlocking motion is carried out by a saleclaid ar a motor. Howev~r, in order to operate the solenoid or the motor, electric power of several watts or several tens of watts must be usually conducted for over lOO msec. That is, electric power of more than 1 joule is consumed when the door is locked and unlocked.
$herefore, in case that a dry battery is used as a power source, service life span of the dry battery is very short even if the dry battery has large capacity, thereby to require exchange of dry batterys within a short time of one year or less than one year.
This type of electric keys are disclosed in Japanese Patent haid Open Publication No. 38800/lg74 and Japanese Patent Publication No. 452~8/1976. An elec.trio key disclosed in the JapaneQe Patent Laid .

Open Publicat:ion No. 3~aO~/l9~4 has an electromagnetic means whicl1 accolllodates a permanent magnet for keeping a movable magne~lc core at a locked and an unlocked pO3i ~iong. ~r~la~ iS, conduction in the electromagnetic mean~ not necessary for maintaining the movable magnetic core at two respective locked and unlocked positions. Ilowe~er, the electromagnetic means must be energized or conducted to move the movable magnetic core ~`rom t~e lacked pasi~ion to the unlocke~ position and vice versa while distinguishing the magnetic flwc of the permanent maynet.
Further, the Japanese Patent Publication No.
452'l8/19'16 also discloses an electromagnetic means having an armature to be operated by an electromagent.
Also in this case, the electromagnetic means must be energized to decrease or cancel the magnetic flwc of a permanent magnet in both cases where the key is locked and unlocked. In thse electromagnetic means, the movable maynetic core and the armature are moved through a space of 2 to 4 mm, respectively. This motion needs a big amount of electric power because ampere-turn for obtaining megnetic flux necessary for a space is in proportion to the length of the space and electric power i5 in proportion to the squre of the ampere-turn.

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lZ98716 Accordingly, as these disclosed electric keys require a big amount of electric power, the life span of dry batteries used for these keys are very short.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an electric key which requires only a small amount of electric power and can be operated in stabilized fashion.
According to this invention, there is provided an electric ~ey having a latch head movable into and out of a Xey hole, and locking means for locking the latch head the electric Xey comprises: (a) movable means for supporting the locking means thereon so that the locking means is moved between a position where the latch head is locked in the key hole and a position where the latch head is released from the key hole; (b) self-holding type electromagnetic means for attracting the movable means thereto in its nonconductive state so that the locking means is urged into the position where the latch head is locked and for releasing the movable means in its conductive state so that the locking means is moved into the position where the latch head is released from the key hole; and (c) returning means for returning the movable means from a position where the movable means is released from the electromagnetic means so that the locking means releases the latch head to a position where the movable means is attracted by the electromagnetic means so that the locking means is urged toward the direction where the locking means locks the latch head in a state wherein the locking means releases the latch head, the returning means being moved together with the latch head when the latch is operated by rotation of a door knob.

ycc/sp 3 BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings;
Fig. 1 is a diagrammatic view showing an ~ ,~

ycc/sp 3a lZ98716 eLectric key accordlny ~o this invention in a locked state;
Fiy. 2 is a diagrammatic view of the same showing a state wherein the key is unlocked.
F'i(J. ~ is a diagrammatic view of the same sl~owilly a state whereill a door knob is rotated; and, Fiy. 4 is a diagrammatic view of the same showi~g a state wherein a door knob is released after the door i5 opellecl.
DL~ITAILED DESCKIPTION OF THE INVENTION
Fig. 1 is a diagrammatic view of an embodimellt accordirlg to this invention and shows a locked state of an electric key.
In Fig. 1, the elec-tric key of this invention ha3 a latch head 2 which is insertable into a key hole ~I provided on a side 1ace of a wall 30 when a door 50 is locked. The latch head 2 is formed with a recess 2a at an outer peripheral surface thereof. The latch head 2 is connected to a latch shaft 31 whose rear end has a latch end portion 6. On the peripheral surface of the latch end portion 6, an arched spring piece 16 is provided . The latch end portion 6 is connected with an end of a spring 32, thereby to cause the latch head 2 to be urged toward the key hole H. Along the latch shaft 31 is provided a stop member 8 for ~ . .

lZ98716 s~oppirly the movemen~ of- the latch end portion 6 to~ard a dlrec-tiol) Or ~he key hole H.
The wall 30 has a protection pla~e 4 on its side ~ace o~po~:ife to a front pannel 1 of a key main body (110~ ShOWII) . The Iront pannel 1 is provided with two engayiny operlings 33, 34 for slidably receiving the latch head 2 and a trigger operati~lg mem~er la coo~erating with -the protection plate 4, respectively.
~rhe ~ri~yer opera~ing member 18 has a shaft laa wh~se rear el~ abuts against an L-shaped trigger 19 at its tail por-tion l9a. T21e -trigger 19 comprises the tail ~ortion l~a which extends in vertical direction during a locking state of the door 50, and an arm portion l9b whose rront end is pivotably supported by a pin l9c.
The lower end of the tail portion l9a is connected to one end of a tension spring 20 for urging the trigger 19 to rotate in clockwise direction in Fig. 1. The trigger 19 has a hoo~ portion l9d for cooperating with the rècess 2a formed on the outer surface of the latch head 2.
Near the latch end portion 6 is located an upper end 5a o a lever 5 whose lower end has a rectangular hole 3 for engaying with a knob shaft 52 of a door knob 51 having a rectangular cross-section. Adjacent the engaginy opening 33 is provided a locking block 11 129871~;

WhiCIl is SU~pOl' ted at the front end of a leaf spring 12 an~ wllic~l is guide~ slidably by two stopping blocks 13, 13 wllile supporting a retreating force exerted on the latch llead 2 by the spring 32 in the right ~irectiorl a~ v:iewe~ in Fig. 1. That is, the locking bloclc 11 i9 vertically movable and is in contactable Wi ~h a rear planller I-ace oi the latch head 2, so that retracting ~ovement of the latch head 2 by the biasing force of ~he spring 32 is restrained by the descending lockiny block 11.
The leaf spring 12 is connected to a swingable iron piece 10 which is supported swingably by a pin 40 at the lower end of a support frame 41 having L-shaped configuration. The support frame 41 has a vertical portion 41a and a horizontal portion 41b. On the left side of the horizontal portion 41b is fixed a support plate 42 which is connected to the upper end of the tension spring 15 whose lower end is connected to the left portion of the iron piece 10 with respect to the vertical portion 41a of the support frame 41. The right portion of the iron piece 10 has a projected portion 17 for cooperating the spring piece 16 fixed to the latch end portion 6.
The horizontal portion 41b of the support frame 41 is fixed with a permanent magnet 14 abutting `

~Z98716 ayaills-t tlle uppe.r portioll of the magnetic core 9a of an electromaynet 9 around which coils 9b are wound.
~aglletic flux of the permanent magnet 14 flows in the maglletic core 9a to attract the iron piece 10 in a normal state whereill the electromagnet 9 is cle~nergized. ~owever, when the electromagnet 9 is energized, tl~e magnetlc ~lux from the permanent magne~
1~ i5 callcelled by a magnetic flux produced by the elec~romayne~ 9.
The operation of this electric Xey will now be explained.
Fig. ~ shows a locked state of the door 50.
'l'hat is, the latch head 2 is located in the key hole H
in a state wherein the rear face of the.latch head 2 abuts against ~he lower portion of the locking block 11 to prevent the latch head 2 from moving rearwardly.
Further, at this time, the iron piece 10 is beld on the lower end of the magnetic core 9a by magnetic force of the permanent magnet 14 against the biasing force of the tension spring 15. This locked state is kept by the magnetic flux of the permanent magnet 14 without consuming electric power. The trigger l9 is held in a nonoperating state wherein the tail portion l9a i5 held by the rear end of the trigger operating member 1~ whose front face abuts against the lZ98716 plo~ccl:ion })late 4 on the wa:ll side, while expallding the tensiol- spring 20.
ln thi~ state, if- a man who wishes to open the dooI- 50 inserts a maynetic card or the like into a cocle read-out portion of a card reader, and if the inserted card is judyed as a true or right card, the electromaylle~ g is eneryized. At this time, electric current ~lows kl a direction where i9 decreased or cancelle(l ~lle maynetic I-lux of the permanent magnet 14 lloLdirlg th~ ilon ~iece 10 through the magnetic core 9a of the electromaynet g. Tllerefore, the magnetic flux lor holdillg the iron piece 10 is decreased or weakened whereby the spriny force of the spring 15 becomes larger thall tlle difference in magnetic strength between the permanent magnet 14 and the electromagnet 9. As a result, the iron piece 10 is released from the magnetic force of the permanent magnet 14, so that the iron piece 10 is rotated about the pin 40 in clockwise direction in Fig~ 1.
Fig. 2 shows this state, and accordingly, the locking block 11 slidingly moves upwardly along the stoppiny blocks 13, so that the locking block 11 is disengayed from the rear planner face of the latch head 2, thereby to enable the latch head 2 to retract in the right direction as viewed in Fig. 2. That is, e lock~ (J l1l~ck ll is moved upward from a positlon illdicated by a broken line to a position ind~cated by a sol:i~ line in Fig. 2. At this time the iron piece 1() i9 relia~ly moved by only ~he spring force of the spri1-~ 15 w.ilhoul: collsuminy any electric power in the electromagnet 9. The electromagnet 9 requires only a small amoul~ ol electric power necessary for decreasing or canc~lliny the s~agnetic flux of the permallent magnet 14 until the spring force of the spriny 1~ becomes larger than an attracting force o~
the permanent magnet 14 to release the iron piece 10 ~rom the lower end of tlle magnetic core 9a. Further as the electromagnet 9 is energized to generate magnetic flux in a state wherein the iron piece 10 contacts the lower end of the magnetic core 9, that i3, a magnetic circuit i5 closed only a small amount of electric power is required. In addition, col~duction period of time is very short since very short is period of time from the state wherein the iron piece 10 contacts the lower end of the magnetic core 9a until the state in which iron piece 10 s-tarts to separate there~rom. According to an example,only about 5 msecs. were required as conduction period of time.
In th~s state of Fig. 2, the door 50 is ready to _ g _ i~g8716 ~ell by movil~g lhe :lever 5 manually in the clockwise diIection to retract the latch head 2. Fig. 3 shows a sta~e wllerein tlle latcll head 2 i5 retracted by rotatilly tlle lever 5. Tha~ is, when the lever 5 is SV1UllC3 ill the clockwise directiorl while the upper end 5a of the lever 5 abut3 against the end face ol the la~ch end por~iorl G, the latch head 2 is retracted 1rom the key hole 1~. When the latch end portion 6 is moved in the ri~ht dilection as viewd in Fig. 3, the spriny piece 16 abuts against the projected portion 17 to raise it, whereby the upper surface of the iron piece 10 is attracted by the magnetic force of the permanent maynet 14 on the lower face of the maynetic core 9a. At this time, the lower end of the locking block 11 is in slide contact with the outer surface of the latch head 2 while bending the leaf spring 12 upwardly. P'urther, the trigger 19 is maintained by the trigyer operating member 18 to release the latch head 2.
With this state, if the door 50 is opened as shown in Fig. 4, the trigger operating member 18 is released from the protection plate 4 on the side face of the wall 30, because the front panel 1 of the key main body is moved away from the side face of the wall 30. At this time, if the knob 51 (Fig. 1) connected ~ tlle :lever 5 is .re.leased, that i9, an operator relea:3e:3 h.L3 l~al~l lrom the knob 51, the latch llead 2 iY movetl by a biasintl lorce o~ the spring 32 in the let direc~loll. When the latch head 2 is projected to all inlermediate posit:ion while the upper face of the l~tch heatl 2 slides the lower end face of the locking blc,ck 11, the hook portion l9d of the trigger 19 is engaged with thè recess 2a of the latch head 2 to stop movemell~ oi` the la~ch head 2 in a condition wherein tlle trigger operating member 18 is projected Irom the lront pannel 1 of -the key main body. At this time, the lockillg block 11 is in contact with the upper face of t1le latch head 2. With this intermediate state oI-tlle latch head 2, if the door 50 is closed, the trigger operating member la i5 pushed rearwardly or retracted by the protection plate 4 on the side face of the wall 30 to rotate the trigger 19 in the counterclockwise direction thereby to release the latch head 2 from the hook portion l9d of the trigger 19. As a result, the latch head 2 is projected to a position where the la-tch end portion 6 abuts against the stop mell~ber 3. At this time, as the lower end of the locking block 11 is released from the upper face of the latch head 2, the locking block 11 is lowered to restrain the backward movement of the latch head 2 , , , , ' ' .

1298'716 t'-. S~ Wll ill L;~:ig. l, thereby to lock the door SO.
In tllls em~)odi.melrt, in a normal state, the e LectlomacJIle~ 19 ho:Lds maglletic flux of the permanent maglle~ 1~ to attract the iron piece 10. That is, the electromagllet 19 can be called a magne-tism holding type e:Lectloma(~llet. Ilowever, the magnet 19 can be subs-titute~ for an electromagnet which can hold the iron piece ~0 by other mechanical means in a normal state. In conclusion, a characteristic feature of this invention resides in the use of a self-holding type electromagllet whicll is conducted to operate it only when the electromagnet is changed from a holding state in wllich the magnet holds the iron piece 10 to a releasiny state in wllich the magnet releases the iron piece 10. In case that the electromagnet is returned from the releasiny state to the holding state, a hand-operation upon opening of the door 50 is utilized thereby to decrease consumption of electric power.
Further, in this invention, a combination of the arched spring piece 16 and the projected portion 1'1 fixed to -the iron piece 10 is used as a returning means for pushing upwardly the movable iron piece 10 to return it to the self-holding electromagnet 9.
Ilowever, the above returning means is not limited to this embodiment. The projected portion 1~ is not ~298716 Ilecesc;ar~ v r(~ ire(~ he projected portion 17 may be L~ ovi(ieA on the la~cll eIlcl portion 6 while the arclled spI'ill9 p:iece 16 may be plovided on the iron piece 10.
~].terIIa-tively, the arcIIed spriny piece 16 may ~e plt)vi(led on the upper end of the lever 5 instead of ~ atCII C?lld portion G. In short, so long as a returniI~ meall~ (the spring 16 and the portion 1'1 ) for returIlillc~ tIIe iron piece 10 to a pOSitiOII wllere the ~elI~-holdiIIg electro]n~gIIet holds the iron piece 10 is provided on a movable portion (the latch end portion 6 or the lever 5) wI1ich can be moved by hand, there are no other re~tlictioIls or limitations with respect to l:he returning means.
In t]le above maIlllèr, in this invention, an opera-tion for a locking motion in a series of- motions (unlockirIy, door oper-ing, door closing and lockiny motions) wI~ich needs electric power most in a conventioarIl electric key is carried out by a hand-operation during the door opening motion. That is, the iron piece 10 is returned by the hand-operation in whicII tIIe Iever 5 is rotated, to a position where the piece 10 is attracted on the lower end of the magnetic core 19a while bendiny the leaf spring 12 to store or accumulate a locking lorce by which the locking block 11 is moved downwardly thereby to lock the latch head lZ9~'71~

2. In tl~is illVen~iOIl, a small amount of electric powe.r is use(l ollly wllell the door is unlocked an~ no additiollal electlic power is no-t necessarily required s~ ce a lock:ill(J iorce can be accumulated by the hand-opera-tion, wl~ereby cons.umptiol- of electric power is remarkably decreased. Therefore, in an electric key U3itlg a dry battery, ~lle length of its service life oall be relllarkably prolonyed thereby to obtain an electric key wl~icl~ does not need exchange oi dry ba-ttery duriny 5 to 1~ years to thus facilitate its maintenance and to increase its practicality.
~specially, if tllis electric key is adapted for an au-tomatically locking type electric key for a door of a hotel or the like, high ecconomical key unit is obtainable.

Claims

1. An electric key having a latch head movable into and out of a key hole, and locking means for locking said latch head, said electric key comprising:
(a) movable means for supporting said locking means thereon so that said locking means is moved between a position where said latch head is locked in said key hole and a position where said latch head is released from said key hole;
(b) self-holding type electromagnetic means for attracting said movable means thereto in its nonconductive state so that said locking means is urged into the position where the latch head is locked and for releasing said movable means in its conductive state so that said locking means is moved into the position where said latch head is released from the key hole; and (c) returning means for returning said movable means from a position where said movable means is released from said electromagnetic means so that said locking means releases said latch head to a position where said movable means is attracted by said electromagnetic means so that said locking means is urged toward the direction where said locking means locks said latch head in a state wherein said locking means releases said latch head, said returning means being moved together with said latch head when said latch is operated by rotation of a door knob.

ycc/sp

2. An electric key according to claim 1, wherein said movable means comprises: a swingable iron piece and leaf spring connected to said iron piece to hold said locking means at its end, said movable means being supported by a spring for urging said iron piece so as to be separated from -said electromagnetic means, said locking means abutting the rear face of said latch head to lock it when said latch lead is inserted deeply into said key hole and said iron piece is attracted by said electromagnetic means, said locking means releasing said latch head when said iron piece is released from said electromagnetic means, said locking means slidingly contacting the outer surface of said latch head when said locking means is urged toward the direction where said latch head is locked, and upon retraction of said latch head into a door by rotation of a door knob, said locking means being released from the outer surface of said latch head so as to abut the rear face of said latch head to lock it when said door is closed so that said latch head is deeply inserted into said key hole.

3. An electric key according to claim 1, wherein said electromagnetic means has a permanent magnet for attracting said iron piece through a magnetic core in a nonconductive state of said electromagnetic means, a magnetic flux of said permanent magnet being cancelled or decreased when said electromagnetic means is energized to release said iron piece therefrom so that said locking means releases said latch head.

ycc/sp

4. An electric key according to claim 1, wherein said returning means comprises a spring piece fixed to a latch end portion for cooperating with a projected portion formed on said iron piece, said latch end portion being operated by a rotatable lever connected to said door knob through a knob shaft.

5. An electric key according to claim 1, further comprising rotatable trigger means having an engaging portion that engages a portion of said latch head in order to stop movement of said latch head and trigger operating means for operating said rotatable trigger means in accordance with opening and closing of said door, said trigger operating means being located in a retracted position where its front face contacts a protection plate of a wall so that said trigger means releases said latch head when said door is closed, said trigger operating means being projected so that said latch head is engaged with said engaging portion of said trigger means when said door is opened thereby maintaining said latch head in an intermediate position, said trigger operating means being retracted to rotate said trigger means so that said latch head is released when said door is closed.

6. An electric key according to claim 5, wherein said rotatable trigger means comprises a L-shaped trigger member which is urged by a spring in a direction where its tail abuts against said trigger operating means, said trigger member having a hook portion as said engaging portion for engaging with a recess of said latch head.

ycc/sp