IMPROVEMENTS IN BAYONET CATCH FASTENINGS
Year: 1877

page_text: LETTERS PATENT to Albert Marcius Silber, of Wood Street, Cheapside, in the
City of London, for the Invention of "IMPROVEMENTS IN BAYONET CATCH
FASTENINGS."
Sealed the 16th March 1877, and dated the 18th January 1877.
"6
PROVISIONAL SPECIFICATION left by the said Albert Marcius Silber at
the Office of the Commissioners of Patents on the 18th January 1877.
ALBERT MARCIUS SILBER, of Wood Street, Cheapside, in the City of London.
IMPROVEMENTS IN BAYONET CATCH FASTENINGS."
My Invention relates to improvements in fastenings of the kind commonly known
as "bayonet catch" fastenings, whereby a cylindrical case, cap, or ring, is secured on an
interior cylindrical body or core, the object of my improvements being to simplify
the construction and action of such fastenings, as I will now describe.
The bayonet catch fastening as usually constructed consists of a stud fixed on the
core which takes into a notch formed in the cap or case, this notch being of
L shape, one part parallel to the axis, and the other part forming a right angle
therewith.
In order to put on the cap two movements are necessary, one in the direction of
the axis, and the other in the plane of rotation; and in order to take off the cap the
same movements have to be made in the reverse order. Moreover the notch and
stud present themselves externally, and in many cases this is objectionable.
According to my improved construction instead of cutting a notch through the
material of the cap I form in the interior of the cap, near the edge of its lip, a cir-
cular groove of sufficient depth to take the stud, and at one part of the circumference
of the cap I make an opening into this groove for the admission of the stud, but
instead of making this opening in a direction parallel to the axis I make it at a
considerable inclination thereto, so that the stud has to enter the groove in a
helical direction.
In putting on the cap it is therefore only necessary to turn it round with a
certain pressure in the direction of the axis so that the stud enters the groove, and
in taking off the cap it is only necessary to turn it round in the opposite direction
until the helical mouth of the groove comes to bear on the stud, the inclination
being then sufficient to move the cap longitudinally off the stud.
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page_text: In applying this construction I prefer to employ two or more studs spaced equally
round the core, each with its appropriate groove and helical mouth in the cap, so
that in turning round the cap the pressure of the studs is uniformly distributed. A
like construction is also applicable in an inverted form, that is to say, by fixing the
stud to the cap projecting internally and forming the groove and its helical mouth
on the core, and in this case also it is preferable to have two or more studs spaced
equally round the circumference of the cap.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Albert Marcius Silber in the Great Seal Patent Office on the 16th
July 1877.
_ALBERT MARCIUS SILBER, of Wood Street, Cheapside, in the City of London.
"IMPROVEMENTS IN BAYONET CATCH FASTENINGS.'
"
My Invention relates to improvements in fastenings of the kind commonly known
as " bayonet catch" fastenings, whereby a cylindrical case, cap, or ring is secured on
an interior cylindrical body or core, the object of my improvements being to
simplify the construction and action of such fastenings as I will now describe.
The bayonet catch fastening as usually constructed consists of a stud fixed on
the core which takes into a notch formed in the cap or case, this notch being of
L shape, one part parallel to the axis, and the other part forming a right angle
therewith.
In order to put on the cap two movements are necessary, one in the direction of
the axis and the other in the plane of rotation, and in order to take off the cap the
same movements have to be made in the reverse order. Moreover the notch and
stud present themselves externally, and in many cases this is objectionable.
According to my improved construction, instead of cutting a notch through the
material of the cap I form in the interior of the cap, near the edge of its lift, a
circular groove of sufficient depth to take the stud, and at one part of the circum-
ference of the cap I make an opening into this groove for the admission of the stud,
but instead of making this opening in a direction parallel to the axis I make it at
a considerable inclination thereto, so that the stud has to enter the groove in a
helical direction.
1
In putting on the cap it is therefore only necessary to turn it round with a certain
pressure in the direction of the axis so that the stud enters the groove, and in taking
off the cap it is only necessary to turn it round in the opposite direction until the
helical mouth of the groove comes to bear on the stud, the inclination being then
sufficient to move the cap longitudinally off the stud.
In applying this construction I prefer to employ two or more studs spaced equally
round the core, each with its appropriate groove and helical mouth in the cap, so
that in turning round the cap the pressure of the studs is uniformly distributed.
A like construction is also applicable in an inverted form, that is to say, by fixing 4
the stud to the cap projecting internally and forming the groove and its helical mouth
on the core, and in this case also it is preferable to have two or more studs spaced
equally round the circumference of the cap.
In the accompanying Drawings Fig. 1 represents a section, and Fig. 2 an elevation
of a core and cap with one form of improved catch fastening according to my
Invention.
The core A is made with two studs B projecting outwardly from near its upper
edge. There may however be only one such stud, or there may be three, or more,
but practically two are sufficient. The cap C is made with an internal groove of
sufficient size to admit the studs B, and parts of the edge of this groove are cut 5
away obliquely, as shewn at c, for the entrance of the studs when the cap is put on,
and for their exit when the cap is taken off. By cutting these notches obliquely at
their back edges, the putting on and taking off of the cap are facilitated, as in the

page_text: former case it is only necessary to press the cap down and turn it round till the
studs find an entrance into the groove, and in the latter case it is only necessary to
turn the cap round in the reverse direction till the oblique edges of the notches
meeting the studs cause the cap to rise clear of them. Fig. 3 represents a section,
and Fig. 4 an elevation of a modification of this fastening, the studs being in this
case fixed to the cap projecting inwards, and the groove in which they engage being
formed on the outside of the core.
Having thus described the nature of my Invention and in what manner the same
is to be performed, I claim the construction of bayonet catch fastening for securing
a cylindrical cap case or ring on an interior cylindrical body or core consisting of
one or more studs, on the one part entering a groove, in the other part by notches
having oblique or helical edges, substantially as and for the purposes herein set
forth.
In witness whereof, I, the said Albert Marcius Silber, have hereunto set my
hand and seal this Sixteenth day of July, in the year of our Lord One
thousand eight hundred and seventy-seven.
A. M. SILBER. (L.S.)