IMPROVEMENTS IN FORKS FOR AGRICULTURAL AND OTHER PURPOSES PROVISIONAL SPFICATION
Year: 1883

page_text: LETTERS PATENT to Gustav Pickhardt of Hagen, Westphalia, German
Empire for an Invention of "IMPROVEMENTS IN FORKS FOR AGRICULTURAL
AND OTHER PURPOSES
PROVISIONAL SPECIFICATION loft by the said Gustav Pickhardt at the
Office of the Commissioners of Patents on the 16th April 1883.
GUSTAV PICKHARDT of Hagen, Westphalia, German Empire
IN FORKS FOR AGRICULTURAL AND OTHER PURPOSES "
"IMPROVEMENTS
a communication [sic]
This invention relates to the mode of fixing the prongs of forks for agricultural
and industrial purposes, such as forks for roots, chaff, dung, hay and the like,
whereby I am enabled to conveniently and rapidly replace damaged prongs.
Although numerous attempts have been made to solve this problem, no mode of
fixing the prongs in a suitable manner has hitherto been devised; all those hereto-
fore constructed have the disadvantage, that they are too complicated and that the
prongs by degrees get loose. Both of these defects are obviated by the present
invention.
In carrying the said invention into practice the back of the fork is made of an
iron or steel bar, which may be of either rectangular, square or round transverse
section, or may have rounded edges.
The said bag must be strengthened at those places where the prongs are fixed.
The prongs are provided at one end with an enlarged, wedge-shaped foot by means
of which they are fixed in the back. In some cases the back is, for this purpose,
provided with a wedge-shaped dove-tailed incision, while in other cases conical
boles of rectangular section are made in the back. The feet of the prongs are
made to correspond with these holes.
The prong is pushed from underneath upwards into the dove-tail groove in the
back. In using the fork the prongs are continually being pushed in more firmly,
so that they cannot get loose accidentally. In order to entirely prevent this, it is
only necessary to give the flat side of the foot of the prong a hard blow with a
hammer in the proper direction whereby the side surfaces of the foot are pressed

page_text: against the corresponding surfaces of the dovetail groove in the back and the over-
lapping ends of the feet are slightly upset. By giving the projecting part of these
feet a blow with a hammer the prongs can at once be released from the back
The dovetail groove is on the underside of the back, so that the pressure of the
loaded prongs, will find sufficient resistance in the upper part of the back, and the
projecting part not be in the way when the fork is being used. The dovetail groove
can however, if desired, be on the front side or even on the bottom or the top of
the back; in the latter case the prongs must be bent to correspond therewith.
According to another mode of fixing the prongs the wedge-shaped foot is tapered
from one end towards the point of the prong, and it is inserted and fixed by means
of a blow with a hammer on the end of the foot. Moreover the dovetail groove
can be either on the bottom or the top of the back. In order to guard entirely
against any unintentional slackening of the prongs by this construction, a set-screw
can be applied, the point of which enters the enlarged foot.
In some cases the foot of the prong is fixed in a tapered hole of rectangular
section, which tapers either from below upwards, or from the top downwards.
The prongs can be inserted from the front or the rear of the back of the fork,
instead of from underneath upwards or from the top downwards, in which case the
root of the prong has to be bent to correspond. The prongs can also be secured, if
necessary, by means of a screw.
The back can in all cases be strengthened at the place where the prong is
inserted.

page_text: of a blow with a hammer on the end of the foot. Moreover the dovetail groove
can be either on the bottom or the top of the back A.
In order to provide against any unintentional slackening of the prongs in this
construction, a set screw d. Figure 6 can be applied, the point of which enters the
enlarged foot.
In the modification shown in Figures 7 to 10, the foot of the prong is fixed in a
tapering hole of rectangular section, which tapers either from below upwards as
in Figures 7 and 8, or from the top downwards as shown in Figures 9 and 10.
The prongs can be inserted from the front or the rear of the back of the fork,
instead of from underneath upwards or from the top downwards, as shown; in
which case the prong has to be bent to correspond.
The prongs may be secured, if necessary, by means of a screw d as shown in
Figure 10. The back in this case is preferably strengthened, as shown, at the
place where the prong is inserted. Or the said prongs may be secured by means
of nuts as shown in Figures 11 and 12, the smaller ends of the tapering feet
of the prongs being screw-threaded for the purpose. Another modification is
illustrated in Figures 13 and 14. In this case the foot b of the prong is of either
prismatic or cylindrical form and is provided with a collar i which bears against
one side of the bar A, the prong being secured by means of a nut f screwed upon
the said prong at the opposite side of the bar to the collar i.
If desired the foot of the prong may be screw-threaded and screwed into the
back A as shown in Figure 15. It is obvious that the feet of the prongs may,
except in the construction shown in Figure 15, be of triangular, square, rectangular,
or other suitable form, as shown in Figure 16.
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I claim :-
In a fork for agricultural or other purposes, the prongs a secured to the back A
of the said fork by means of feet wedge-shaped or dovetailed as described with
reference to Figures 1 to 12, or provided with collars i and nuts f as described with
reference to Figures 13 and 14, or by screwing the said feet into the back of the
fork as described with reference to Figure 15 of the accompanying drawing for the
purposes specified.
In witness whereof I the said Gustav Pickhardt, have hereunto set my hand
and seal this Twelfth day of October in the year of our Lord one thousand
eight hundred and eighty three.