US3918750A

US3918750A - Locking devices for doors

Info

Publication number: US3918750A
Application number: US422314A
Authority: US
Inventors: Hajime Okamoto
Original assignee: Yashica Co Ltd
Current assignee: Yashica Co Ltd
Priority date: 1972-12-12
Filing date: 1973-12-06
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11

Abstract

The locking device comprises a latch provided for a door or a casing, a first slidable member having a hook adapted to cooperate with the latch and provided for the casing or the door, spring means to bias the first slidable member in the longitudinal direction for engaging the hook with the latch, a second slidable member driven by the first slidable member, and a manually operated locking member for normally locking the second slidable member.

Description

United States Patent m1 [1 11 3,918,750 Okamoto 1 Nov. 11, 1975 I LOCKING DEVICES FOR DOORS 105mm ill/Wot) Humphries to 70/70 x 3.5.3 3 ..7()b7X [75] lnventor: HaJlme ()kamoto. Kawasaki, Japan 7 h h l) m )7 MIN) {73] Assignee: Yashiea C0., Ltd.. Tokyo. Japan Irimur 1.;'.\'um1'm'/'Riehard Moore 22 Filed: Dan 6 19.73 Allurner, i-igvnl, 0r I'1rn1( l'lllflCS W. Helzer [2i Appl. No.: 422,314 [57] ABSTRACT Foreign Application Priority Data The locking device C(IIHPIISSS 11 latch provided for it door or a easing, u hrst sliduble member having ti 12,1972 Japan --47|43605 hook adapted to cooperate with the latch and provided for the casing or the door, spring means to bias [52] U.S. Cl 292/106; 292/127 the first sliduble member in the longitudinal direction [51 1 Int. Cl.'- EQSC 1/06 for engaging the hook with the latch. 11 second sliduble l l Field Of Search 70/69, 70, 71 72. 73. member driven by the first sliduble member and at 70/74, 75, 76; 292/l06. 127, 150. 174, DIG. manually operated locking member for HUITIlLlll) lock- 48 ing the second slidnble member.

[56] References Cited 6 Claims. 5 Drawing Figures UNITED STATES PATENTS I 1546149 3/1951 BOWZCI' 292/150 X US. Patent N0v.11, 1975 Sheet10f3 3,918,750

US. Patent Nov. 11, 1975 S heet20f3 3,918,750

6 5.1) WWW US. Patent Nov.11, 1975 Sheet30f3 3,918,750

LOCKING DEVICES FOR DOORS BACKGROUND OF THE INVENTION This invention relates to a door locking device for locking the door of a casing adapted to house a photographic camera for example.

A locking device for locking a door to a casing generally comprises a latching member provided for either one of the door and the casing and a slidable member mounted on the other of said door and casing and including a hook engageable with said latching member. A locking device having a construction described above, however, has a tendency of accidental opening of the door so that it is impossible to apply such a locking device for a door of a casing which is required to maintain its temperature or pressure at a predetermined value or to maintain photosensitive material contained in the casing in the dark.

For example, where such a door locking device is used for a rear lid of a photographic camera, the outer end of the slidable member is bent up to project to the outside of the casing to be operable by the fingers of the user. Thus, the user of the camera operates such a projected end with his fingers to open and close the rear lid of the camera. However, such a projected end may be readily engaged by clothes or casing of the camera causing an accidental opening of the rear lid when the camera is carried without housing it in the casing or when the camera is taken out of the casing. For this reason, in the prior art locking devices, for the purpose of preventing such an accidental opening, the force of a spring adapted to hold the slidable member in the locked position has been increased or a locking button for locking the movement of the slidable member has been provided so that unless the locking button has been operated the slidable member can not be moved. With the former, it is impossible to operate the locking device with a small force whereas with the latter construction as the locking button and the slidable member immediately restore their original state, that is the locked state, it is necessary to manually operate the locking button so as to free the slidable member in order to lock the door. I have proposed an improved construction that can obviate this disadvantage. According to this improved construction the hook provided for the slidable member is made to be resilient so that the hook is flexed to permit engagement with the latch when the door is closed. However, such a hook becomes brittle in a relatively short interval and requires strict control of the quality of material and high degree of accuracy of assembling.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved locking member for a door adapted to close an opening of a casing and with respect to which it is not necessary to operate a locking button for closing or opening the door.

Another object of this invention is to provide an improved door locking device which can be readily fabricated without a high degree of accuracy, can prevent accidental opening of the door and has a rigid and compact construction.

Still another object of this invention is to provide an improved door locking device wherein the relative movement of various parts of the locking device is small thus decreasing damage and fault caused by wear.

In accordance with this invention, these and further objects can be accomplished by providing a locking device for a door adapted to close an opening of a casing comprising a latch, a first slidable member having a hook adapted to cooperate with the latch, the latch being provided for one of the door and the casing and the slidable member being provided for the other, means to bias the first slidable member in the longitudinal direction for engaging the hook with the latch, a second slidable member driven by the first slidable member, and a manually operated locking member for normally locking the second slidable member.

BRIEF DESCRIPTION OF THE DRAWINGS The invention can be better understood from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is an exploded perspective view of a locking device embodying the invention and applied to a rear lid of a photographic camera;

FIG. 2 is a plan view of an assembled locking device;

FIG. 3 shows a section taken along a line III-11] in FIG. 2

FIG. 4 is a view similar to FIG. 3 with the locking device shown in the unlocked position and FIG. 5 is an exploded perspective view of a modified embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The door locking device of this invention shown in FIGS. 1 to 4 of the accompanying drawings is used to lock the rear lid or door 2 which is hinged to the body or casing 1 of a photographic camera. The free end of the lid 2 is bent up and a plate 4 having a latch 3 at the center is secured to the outside of the bent up portion. A pair of

pins

5 and 6 are secured to one side of the camera body 1 to which the plate 4 is secured to support a cover plate 7 which is secured to the

pins

5 and 6 by means of screws 8 and 9 as shown in FIG. 3.

Slidable members

12 and 13 having

slots

10, 11, 10' and 11 adapted to receive

pins

5 and 6 are disposed in a space between the cover plate 7 and the camera body 1. The

slidable members

12 and 13 are superposed each other and are slidable in the longitudinal direction.

One end of upper slidable member 12 extends beyond the corresponding end of the cover plate 7 and is formed with a flange 14. A key hole 15 having a diameter of D and a slot 16 having a width d and contiguous to key hole 15 are formed through slidable member 12 and a pin 17 is secured to the lower surface of the slidable member 12 at about the middle of the length thereof. The lower slidable member 13 is provided with a letter L shaped lateral hook 18 in the same plane as the slidable member 13. The outer end of the hook 18 is slanted as at 18a. On the opposite sides of the key hole 15 and slot 16, the lower slidable member 13 is provided with an elliptical slot 19 having a width D which is substantially equal to or slightly larger than the diameter D of key opening 15 and a slot 20 adapted to receive pin 17. A recess 22 is formed on one surface of the camera body 1 to receive a compression spring 21 having one end engaged with the lower slidable member 13 to urge it in the locking direction. A recess 23 is provided for the camera body 1 beneath key hole 15 and elliptical slot 19 to receive a locking button 25 which is normally urged to project upwardly by a compressed spring 24. The head 26 of the locking button 25 is normally projecting to the outside of an opening 27 through the cover plate 7. The locking button 25 is provided with an annular locking member 28 having an outer diameter corresponding to the diameter D of key opening I5, a reduced diameter portion 29 on the upper side of the locking member 28 and having a diameter corresponding to the width d of slot 16, and a lower flange 30 having a diameter larger than the width of the elliptical slot 19.

When the rear lid 2 is closed, various parts of the locking device assume the positions shown in FIGS. 2 and 3. More particularly, the latch 3 of the stationary plate 4 is positioned in a gap defined between the hook 18 and the lower slidable member 13 thereby locking the same. Under these circumstances, the locking member 28 of the locking button 25 is in a locking engagement with the key hole 15 of the upper slidable member 12 but the lower slidable member 13 is not locked because the width D of the elliptical slot 19 is larger than the diameter of the locking member 28. To release the locking engagement of the locking member 28 with the key hole 15, the locking button 25 is depressed by a finger as shown in FIG. 4 to bring the reduced diameter portion 29 into alignment with the slot 16. At the same time, the flange I4 is pulled to move the upper slidable member 12 in the direction of arrow C shown in FIG. 4. Since pin 17 is engaging slot 20 the lower slidable member 13 is also moved together with the upper slidable member 12, thus disengaging hook 18 from latch 3. When the slidable member 12 is re leased it will be returned from the position shown in FIG. 4 to the position shown in FIGS. 2 and 3 by being pulled by the lower slidable member 13 and the action of return spring 21. As the

slidable members

12 and 13 reset, the locking button is projected upwardly to again lock the slidable member 12.

In order to close the rear lid 2 for the purpose of locking again latch 3 and hook 18, the lid 2 is pressed in the direction of arrow B shown in FIG. 1. When the latch 3 is urged against the inclined surface 180, the lower slidable member 13 is urged in the direction of A. As soon as the latch 3 enters into the gap between the hook 18 and the slidable member 13, the slidable member 13 is reset by the action of the compression spring 21 thus locking latch 3 with hook 18.

According to a modified embodiment shown in FIG. 5, two

slidable members

51 and 52 are arranged in the same plane which correspond to

slidable members

12 and 13, respectively of the previous embodiment. Although the

slidable members

51 and 52 have the same function as the

slidable members

12 and 13, pin 17 is replaced by a hook 55 provided for the slidable member 51. To further stabilize the operation of the

slidable members

51 and 52, a guide wall 56 is provided for the camera body 1 to assist pins 53 and 54. This modified embodiment is suitable where sufficient height is not available to install the locking device.

With the locking device of this invention, even when weak springs are used for biasing the slidable members and the locking button it is possible to prevent any accidental opening of the rear lid or door and the door can be opened and closed with a small force. Finally, it should be noted that two separate manual operations are required to release the locking device, and hence, open the lid or door, as opposed to a single manual operation to effect closing. Hence, the possibility of accidental opening of the lid or door is minimized.

According to this invention it is only necessary to manufacture various parts at high accuracies but it is not necessary to adjust them at the time of assembly.

For this reason, it is possible to decrease the number of process steps for assembly and the cost of manufacturing. Moreover, since the relative movements between various parts are small and since the parts are held stable in respective positions, damage of the parts: due to. wear is small thus decreasing the chance of fault and misoperation.

What is claimed is:

l. A locking device for a door adapted to close an opening of a casing comprising a latch, a linearly slidi able member having a hook slidable along a linear path to engage in interlocking relationship with saidilatch',

said latch being provided for one of said door and cas- 7 ing and said slidable member being provided for the other, biasing spring means to bias said slidable member longitudinally along a linear path in a direction for engaging said hook with said latch, manually operated means engaging said slidable member for longitudinally sliding said slidable member along the linear path in a direction opposite to that of the biasing spring means for releasing the latch, a manually operated locking member engageable with said slidable member for locking the slidable member against movement, and second biasing spring means for normally biasing said locking member into locking engagement with said slidable member.

2. The locking device according to claim I wherein said slidable member comprises first and second slid I able members provided with aligned guide slots adapted to accommodate guide pins secured to said casing, and said first and second slidable members are.-

superposed upon each other and secured together.

3. The locking device according to claiml wherein said slidable member is formed with a key hole and a slot contiguous to and extending into said key hole with said slot having a width smaller than said key hole and said locking member comprises a locking button received in said key hole said locking button having a lower larger diameter portion corresponding to the idiameter of said key hole and an upper reduced diameter. portion having a diameter corresponding to the width of said slot, and said second biasing spring means comprises a biasing spring for normally urging said locking button upwardly for fitting said lower larger diameter portion in said key hole for securing said locking device in a closed position.

4. The locking device according to claim 3 wherein 1 i connected by additional hook means.

Claims

1. A locking device for a door adapted to close an opening of a casing comprising a latch, a linearly slidable member having a hook slidable along a linear path to engage in interlocking relationship with said latch, said latch being provided for one of said door and casing and said slidable member being provided fOr the other, biasing spring means to bias said slidable member longitudinally along a linear path in a direction for engaging said hook with said latch, manually operated means engaging said slidable member for longitudinally sliding said slidable member along the linear path in a direction opposite to that of the biasing spring means for releasing the latch, a manually operated locking member engagable with said slidable member for locking the slidable member against movement, and second biasing spring means for normally biasing said locking member into locking engagement with said slidable member.

2. The locking device according to claim 1 wherein said slidable member comprises first and second slidable members provided with aligned guide slots adapted to accommodate guide pins secured to said casing, and said first and second slidable members are superposed upon each other and secured together.

3. The locking device according to claim 1 wherein said slidable member is formed with a key hole and a slot contiguous to and extending into said key hole with said slot having a width smaller than said key hole and said locking member comprises a locking button received in said key hole said locking button having a lower larger diameter portion corresponding to the diameter of said key hole and an upper reduced diameter portion having a diameter corresponding to the width of said slot, and said second biasing spring means comprises a biasing spring for normally urging said locking button upwardly for fitting said lower larger diameter portion in said key hole for securing said locking device in a closed position.

4. The locking device according to claim 3 wherein said slidable member comprises first and second slidable members provided with aligned guide slots adapted to accommodate guide pins secured to said casing, and said first and second slidable members are superposed upon each other and secured together.

5. The locking device according to claim 1 wherein said slidable member comprises first and second slidable members arranged on the same plane and interconnected by additional hook means.

6. The locking device according to claim 3 wherein said slidable member comprises first and second slidable members arranged on the same plane and interconnected by additional hook means.