US3384722A

US3384722A - Safety switch lock

Info

Publication number: US3384722A
Application number: US619432A
Authority: US
Inventors: Hanke Walter; Klingner Wolfgang
Original assignee: Olympia Werke AG
Current assignee: Olympia Werke AG
Priority date: 1966-03-08
Filing date: 1967-02-28
Publication date: 1968-05-21
Anticipated expiration: 1985-05-21
Also published as: DE1937333U; GB1169616A; CH451970A; NL6701630A; SE329634B

Description

y was w. HANKE ETAL 3,384,722

SAFETY SWITCH LOCK Filed Feb. 28, 1967 INLEAITQ R BY-fif/ $771.04

ATTUR EY f H J.

United States Patent -O 3,384,722 SAFETY SWITCH LOCK Walter Hanke, Sande-Neufeld, and Wolfgang Klingner, Grafschaft, Germany, assignors to Olympia Werke Filed Feb. 28, 1967, Ser. No. 619,432 Claims priority, applicatitn6gsermany, Mar. 8, 1966,

10 Claims. (Cl. 200-50 ABSTRACT OF THE DISCLOSURE Background of the invention Safety switch locks are known which interrupt a circuit when a closure is opened, particularly, it is known to provide means for interrupting the circuit of the drive motor of an electric typewriter when the top cover of the typewriter, or of an accounting or other business machine, is opened. However, the safety locks according to the prior art are rather complicated and consist of a g at many parts so that the cost of manufacture and assembly is high.

Summary of the invention It is the main object of the invention to provide a safety switch lock which will automatically lock the main switch of an apparatus in a circuit breaking position when a a closure of the apparatus is opened and permits access to electric circuit parts of the apparatus.

Another object of the invention is to automatically shift the main switch of an apparatus to a circuit breaking position when a closure is opened.

With these objects in view, the present invention relates to a safety switch lock having locking means controlled by a closure to lock the main switch of an apparatus in a circuit breaking position when the closure is opened, and to first move the main switch to the circuit breaking position if it is in a circuit making position when the closure is opened.

One embodiment of the invention comprises a casing, for example a typewriter casing, having closure means, for example the top cover of a typewriter, movable e tween a first closed position and a second open position; switch means mounted on the housing and having an actuator movable between a first circuit making position and a second circuit breaking position; locking means connected with the closure means for movement therewith to first and second positions and having lost motion coupling means in the form of a pin and slot connection with the actuator; and biasing means for moving the locking means from the second position to a locking position locking the actuator.

Due to the lost motion coupling means, the actuator remains in the circuit breakingposition when the locking means and closure means move to the second positions, but if the actuator is in the circuit making position, it is coupled by engagement of a pin on the actuator with the end of a slot in the locking means and is moved to the circuit breaking position when the closure is opened.

The slot of the locking means has a transverse locking slot portion permitting movement of the locking means to the locking position only if the actuator is in the 3,384,722. Patented May 21, 1968 circuit breaking position, or has been shifted to the circuit breaking position by the locking means.

In the preferred embodiment of the invention, the locking means is an elongated locking member mounted on a pivot means of the housing for longitudinal movement between the first and second positions, and for turning movement between the second and locking positions. A spring'urges the locking member to follow the opening movement of the closure, which is possible due to the provision of a guide slot in the locking member receiving the pivot means and permiting longitudinal and turning movement of the locking member.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawing FIG. 1 is a fragmentary elevation, partially in section, illustrating a safety switch lock of an electric typewriter in an operational position in which the closure of the typewriter is closed, and the switch is in a circuit breaking position;

FIG. 2 is a fragmentary elevation corresponding to FIG. 1, but illustrating the switch in the circuit making position; and

FIG. 3 is a fragmentary elevation corresponding to FIGS. 1 and 2, and illustrating the top cover of the typewriter in an open position, and the switch locks in the circuit breaking position.

Description of a preferred embodiment Referring now to the drawing, the housing of a typewriter or like machine, has lateral walls 1, one of which is illustrated. Housing wall 1 carries a fixed pivot passing through an elongated guide slot 3a provided in a slanted end portion of a locking means 3 which has a projection 30 abutting the closure or top cover 5 of the typewriter under the action of a spring 4 which is secured to locking means 3 and to a transverse lug 1a on housing wall 1. When closure 5, which is only partially shown, is opened, locking means 3 is urged by spring 4 to follow closure '5 while projection 30 slides on the same until further movement with closure 5 is prevented by the engagement of pivot means 2 with one end of guide slot 3 in the position of FIG. 3.

Housing wall 1 carries a cover plate 6 on a pair of brackets 6b which has a slot 60 having an end bounded by an edge 6d. Locking means 3 is a fiat locking bar aligned with slot 6c, but in the positions shown in FIGS. 1 and 2, the end of locking bar 3 slidingly abuts the bottom face of cover plate 6 under the action of spring 4 which tends to turn the locking bar 3 in counterclockwise direction. However, when due to the opening of closure 5, locking bar 3 is moved by spring 4 to the position shown in FIG. 3, the end of locking bar 3 arrives at the edge 6d of the slot or cutout 60 so that spring 4 can turn locking bar 3 about pivot means 2 to a position located in slot or cutout 6c and being locked against movement to the right as viewed in the drawing by the edge 6d, while being also locked against movement to the left by pivot means 2 since the same is located in the end of guide slot 3a.

A main switch 8 is mounted in the housing of the apparatus and has an actuator including first part 8a having a slot, a second part 10 carrying a coupling pin 11 passing through a slot 3b in the end portion of locking bar 3, a pair of washers 12 and 13 mounted on pin 11 on opposite sides of locking bar 3 and slot 3a, and an adjustment screw 9 which is threaded into part 10 and secures the same with coupling pin 11 to part 8a, permitting adjustment of the length of the actuator and of the position of coupling pin 11 in relation to locking bar 3 and its slot 3b.

Slot 3b has a first elongated circular part permitting turning movement of the actuator with coupling pin 11 between the positions shown in FIGS. 1 and 2 while locking bar 3 remains in the same position. This movement is controlled by a manually operated member 7 which has a downwardly projecting operating member 7a having a lower forked end forming an open slot 7b in which a portion of coupling pin 11 is located.

In the positions shown in FIGS. 1 and 2, the typewriter is in an operative condition, and closure 5 is closed. The manually operated member 7 can be shifted from the position of FIG. 1 in which coupling pin 11 is located at one end of slot 3b and switch 8 is in its circuit breaking position, to the position of FIG. 2 in which coupling pin 11 is located at the other end of slot 3b and the

actuator

8a, 10, 11 is shifted to place the switch in the circuit making position.

As best seen in FIG. 1, slot 6b has a locking slot portion at one end which extends transverse to the direction of slot 3b. When closure 5 is opened, and locking bar 3 moves to the end position shown in FIG. 3, coupling pin 11 is located in the region of the transverse slot portion 3d so that the above-described pivotal movement of locking bar 3 to the position of FIG. 3 located in slot or cutout 60 is possible due to the fact that coupling pin 11 enters the portion 3d. Since pin 11 is located in slot portion 3d, the

actuator

8a, 10, 11 cannot turn relative to locking bar 3 which is locked by the edge 6d of cutout 6c.

Operation In the normal operative position of the typewriter shown in FIGS. 1 and 2, the closed closure 5 holds locking bar 3 against the action of spring 4 by engaging projection 30. Assuming that switch 8 is in the circuit breaking position shown in FIG. 1, coupling pin 11 is located at the left end of coupling slot 3b, and it is possible to shift switch 8 to the circuit making position in which coupling pin 11 is located at the right end of slot 3b and in the region of the locking slot portion 30, as shown in FIG. 2.

Assuming that the switch is in the circuit breaking position shown in FIG. 1, and closure or top cover 5 is opened for cleaning the types or exchanging the ribbon, locking bar 3 follows the upward movement of closure 5 under the action of spring 4 until the lower end of guide slot 3a abuts pivot means 2, as shown in FIG. 3. The movement of locking bar 3 is rearward and upward due to the position of guide slot 3a. When during this movement of locking bar 3, coupling pin 11 arrives at the right end of guide slot 3b, locking bar 3 is turned about pivot 2 by spring 4 to the locking position shown in FIG. 3 which is possible due to the fact that the end of locking bar 3 is now located rearwardly of the edge 6d of slot or cutout 6c, and furthermore due to the fact that locking slot portion 3d is now aligned with coupling pin 11. In the position of FIG. 3, locking bar 3 is locked against movement to the left and to the right, and locking slot portion 3d locks coupling pin 11 and the actuator against turning movement to' the circuit making position.

When closure 5 is again closed, it engages first projection 30 and displaces the same downward so that locking bar 3 is first turned about pivot 2 in clockwise direction until its end moves out of slot or cutout 6c, and coupling pin 11 is again located in the coupling slot 3b. Further downward movement of closure 5 displaces projection 30 so that locking bar 3 is moved in longitudinal direction toward the right as viewed in FIG. 3 with guide slot 3a moving along the stationary pivot 2, and the end portion of locking bar 3 sliding on the bottom face of cover plate 6 to the position of FIG. 1. The position of the manually operated member 7, and the circuit breaking position of the switch are not changed.

If the manually operated member 7 is in the position of FIG. 2, holding the actuator 8a to 11 in the position in which switch 8 closes the circuit of the typewriter, and closure 5 is opened, spring 4 urges locking bar 3 to move to the left as viewed in FIG. 2 and to turn in counterclockwise direction. As long as the end portion of locking bar 3 slides on the bottom face of cover plate 6, locking bar 3 moves rearward and upward under the action of spring 4 toward the left, displacing coupling pin 11 to the left, since coupling pin 11 abuts the end of coupling slot 3b. In this manner,

actuator

8a, 10, 11 is turned from the circuit making position of FIG. 2 to the circuit breaking position, and when the end of locking bar 3 reaches the edge 6d ofslot or cutout 6c, spring 4 turns locking bar 3 about pivot 2 so that locking slot portion 3d receives coupling pin 11 and locks the same together with the switch actuator to hold the switch in the circuit breaking position. The manually operable member 7 is shifted by the coupling pin 11 which is located in slot 7b of operating member 7a. When closure 5 is fully opened, the position of FIG. 3 is again obtained, with the switch locked in the circuit breaking position.

When closure 5 is closed again, projection 30 is engaged, and locking bar 3 turned in clockwise direction out of slot 6c while coupling pin 11 assumes a position located at the end of the longitudinal coupling slot 60. Further downward movement of closure 5 displaces locking bar 3 to the right until the position of FIG. 1 is again obtained, the manually operable member 7 and the switch remaining in the circuit breaking position until shifted by the operator.

From the above description of an embodiment of the invention, it will become apparent that coupling slot 3]) and coupling pin 11 constitute a lost motion coupling means for coupling locking bar 3 in the position of FIGS. 1 and 2 to the switch actuator for movement toward the left to follow closure 5 toward the open position. The lost motion coupling means 11, 3b permit shifting of the actuator from the circuit breaking position of FIG. 1 to the circuit making position of FIG. 2 by operation of the manually operated member 7. Spring 4 is a biasing means for moving locking bar 3 in longitudinal direction together with the closure 5, and for turning the locking bar in a transverse direction to place coupling pin 11 in the locking slot portion 3d in the locking position of locking bar 3 shown in FIG. 3.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of safety switch locks ditferingfrom the types described above.

While the invention has been illustrated and described as embodied in a safety switch lock for a typewriter for automatically shifting a switch to a circuit breaking position when a closure of a housing is opened, and for locking the switch in circuit breaking position as long as the closure is open, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Safety switch lock, comprising, a casing having closure means movable between a first closed position and a second open position; switch means mounted on said housing and having an actuator movable between a first circuit making position and a second circuit breaking position; locking means connected with said closure means for movement therewith and being a first position when said closure means is in said first position and being in a second position when said closure means is in said second postion, said locking means having lost motion coupling means connected with said actuator so that the same remains in said second position thereof when said locking means and closure means move to said second positions of the same, and so that said actuator in said first position is coupled with said locking means in said first positon of the same and moves to said second position when said locking means moves to said second positions; and biasing means for urging said locking means to a locking position locking said actuator when said locking means and said actuator are both in said second positions so that said actuator is locked in said circuit breaking position when said closure is in said open position.

2. Safety switch lock as claimed in claim 1 comprising mounting means mounting said locking means on said housing for movement in one direction between said first and second positions, and for turning movement in a direction transverse to said one direction between said second and locking positions.

3. Safety switch lock as claimed in claim 2 wherein said mounting means include pivot means secured to said casing, and wherein said locking means has a guide slot receiving said pivot means; and wherein said biasing means urges said locking means into engagement with said closure means so that said locking means in said first position follows said closure means to said second open position and assumes said second position thereof.

4. Safety switch lock as claimed in claim 3 wherein said locking means has a portion engaging said closure means in said first closed position; and wherein said biasing means includes a spring secured to said housing and to said locking means and urging said locking means to said second and locking positions of the same.

5. Safety switch lock as claimed in claim 1 wherein said lost motion coupling means includes a coupling pin on said actuator and coupling slot in said locking means slidably receiving said coupling pin, said coupling pin being located at first and second ends, respectively, of said coupling slot when said locking means is in said first position, and said actuator is in said first and second positions, respectively, said second end of said coupling slot having a transverse locking slot portion; and wherein said biasing means urge said locking means in said second position to move with said locking slot portion to said locking position in which said coupling pin of said actuator in said second position is located in said locking slot portion and is locked with said actuator so that the same cannot be moved to said first circuit making position.

6. Safety switch lock as claimed in claim 1 wherein said casing is a part of an electric typewriter, and wherein said closure means is the top cover of the typewriter.

7. Safety switch lock as claimed in claim 1 wherein said switch means includes a manually operable member connected with said actuator for movement therewith and being shifted when said actuator is shifted between said circuit breaking and circuit making positions.

8. Safety switch lock as claimed in claim 1 wherein said biasing means urges said locking means to move to said second position, and from said second position to said locking position; and wherein said locking means abuts said casing in said first position and is released by said casing in said second position for movement to said locking position.

9. Safety switch lock as claimed in claim 1 wherein said locking means is a locking bar having a guide slot, and a coupling slot with a transverse locking slot portion; comprising a pivot means on said casing located in said guide slot; wherein said biasing means is a spring connecting said locking bar with said casing and urging said locking bar to follow said closure means to said second open position, and to turn to said locking position; wherein said actuator has a coupling pin located in said coupling slot and forming with the same said lost motion coupling means, said coupling pin being located in said locking slot portion in said locking position of said locking bar; wherein said locking bar has an end portion sliding on said casing in said first position and being released by the same in said second position to abut a casing portion whereby movement of said locking bar in said locking position to said first position is blocked so that movement of said actuator to said first position of the same is blocked.

10. Safety switch lock as claimed in claim 9 wherein said switch means includes a manually operable member connected with said actuator for movement with the same.

No references cited.

ROBERRT K. SCHAEFER, Primary Examiner.

I. R. SCOTT, Assistant Examiner.