Improvements in Electric Switches.
Year: 1899

page_text: Improvements in Electric Switches.
I, RENTO WOLTER HENDRIK HOFSTEDE-CRULL, of Borne'sche Straaf, Hengelo,
Ober Yssel, in the Kingdom of Holland, Engineer, do hereby declare the nature
of this invention to be as follows:-
My invention relates to electric lever or snap-switches.
In these switches it is of importance that the movable contact piece (the
tongue) shall make intimate contact with the fixed contact pieces and when
switched on shall not spring out, and that the springs which cause the quick
momentary movement shall only be in tension when the switch is not closed.
It has before been proposed to meet the first of these requirements by link-
ing the tongue to the hand lever so that a pulling or sliding movement is
obtained in the contacts before switching off.
A time limit is, however, not given to the sliding movement of the movable
contact or tongue and furthermore the spring of the said contact must always be
at full tension whilst in the case of other known lever switches wherein the
spring arrangement is only in tension when the switch is open, neither a sliding
contact piece nor a time limit to the movement of the same is possible.
In my invention all the above requirements are met and to this end I pivot the
lever to the base plate and the tongue or movable contact piece to the lever, the
said movable tongue fitting into the contact pieces and being further controlled
on the lever by a spring.
A catch which a spring tends, to move inwards and which pivots upon the
base plate engages with its nose over the inwardly inclined end of the movable
contact piece and thereby holds it in position.
When the lever is raised the spring controlling the movable contact is put into
tension whilst the said contact by reason of the eccentric arrangement of its
pivot with respect to the pivot of the lever is moved under the nose of the pawl
transversely between the fixed contacts.
The moment the inclined end of the movable contact leaves the nose of the
pawl the lever sprin which has been meanwhile placed in tension snaps the
tongue radially against the lever and thereby quickly lifts it from the fixed
contact pieces.
If, on the contrary, the switch be again closed by depressing the lever the
wedge, shaped front end of the movable contact presses against the nose of the
pawl and turns the said pawl so as to put its spring in tension, until the pawl
snaps into position and again locks the movable contact.
T 00th day of Tu1 1800
G. F. REDFERN & Co.,
4, South Street, Finsbury London,
Agents for the Applicant.

page_text: Improvements in Electric Switches.
1, RENTO WOLTER HENDRIK HOFSTEDE-CRULL, of Borne'sche Straat, Hengelo,
Über Yssel, in the Kingdom of Holland, Engineer, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
Jarly described and ascertained in and by the following statement:
My invention relates to electric lever or snap-switches.
In these switches it is of importance that the movable contact piece (the
tongue) shall make intimate contact with the fixed contact pieces and when
switched on shall not spring out, and that the springs which cause the quick
momentary movement shall only be in tension when the switch is being opened.
It has before been proposed to meet the first of these requirements by link-
ing the tongue to the hand lever so that a pulling or sliding movement is
obtained in the contacts before switching off.
A time limit is, however, not given to the sliding movement of the movable
contact or tongue and furthermore the spring of the said contact must always be
at full tension whilst in the case of other known lever switches wherein the
spring arrangement is only in tension when the switch is opened, neither a sliding
contact piece nor a time limit to the movement of the same is possible.
In my invention all the above requirements are met and to this end I con-
struct switches as shewn in the accompanying drawing, in which:-
Figure 1 is a side view shewing the switch closed, and
Figure 2 is a similar view shewing the manner in which the switch operates.
A is the operating lever, the said lever being pivoted to the base plate p at
the point and is the tongue or movable contact piece the said contact piece a
being pivoted at c to the lever and fitting into the spring contacts b, b and being
further controlled on the lever A by springs d.
A catch e which a spring g tends to move inwards and which pivots upon the
base plate p engages with its nose e¹ over the inwardly inclined or bevelled
end a of the movable contact piece a and thereby holds it in position.
When the lever A is raised (as shewn in Figure 2) the spring d controlling the
movable contact a is put into tension whilst the said contact, by reason of the
eccentric arrangement of its pivot e with respect to the pivot f of the lever A
is moved from under the nose e' of the pawl e transversely between the fixed
contacts b, b.
The moment the inclined end a¹ of the movable contact a leaves the nose e¹
of the pawl the lever spring d, which has been meanwhile placed in tension,
snaps the tongue a radially against the lever and thereby quickly lifts it from
the fixed contact pieces b, b as shewn in the broken lines Figure 2.
If, on the contrary, the switch be again closed by depressing the lever A the
wedge shaped front end a¹ of the movable contact a presses against the nose e¹
of the pawl e and turns the said pawl so as to put its spring in tension as shewn
in the broken lines Figure 2, until the pawl snaps into position and again locks
the movable contact a.
It will be obvious that the spring d arranged between the lever A and contact
tongue a, can be replaced by a spring which is applied against the rear edge 2
of the tongue and, furthermore, that the said tongue could be arranged to slide
backwards instead of forwards if desired.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a lever or snap switch having a spring which is only in tension whilst

page_text: the switch is being opened and a contact tongue adapted to slide between fixed
spring contacts, the arrangement of a catch which secures the switch in the
closed position and limits the sliding movement of the contact tongue in the
fixed spring contacts, substantially as herein before described.
2. Electric switches constructed substantially as hereinbefore described and
illustrated in the accompanying drawing.
n1 L
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury London,
Agents for the Applicant.