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Diana Airguns - Mayer and Grammelspacher Patents

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Garvin
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Diana Airguns - Mayer and Grammelspacher Patents


   
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Garvin
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Diana Giss recoilless design - patent drawing.

 

Here is one of the original Kurt Giss patent drawings from 1956, the design on which Diana based its recoilless match rifles and pistols.

But you will see that in fact Diana modified their version to include a dummy, opposing rear piston which acts as a counterweight to the forward compression piston, cancelling recoil but not adding to compression at all. The low power output required for a 10m rifle allowed relatively light duty and light weight materials to be used for the internal parts.

One recoilless air rifle broadly faithful to the Giss design is the Whiscombe (now out of production but made until 2009 by John Whiscombe in the UK), which has twin pistons that travel towards each other, causing greater air compression and thus higher power, but also with zero recoil.

Admin added 08/06/2022



   
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Garvin
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Diana's double pull trigger (1930s).

 

Here are some schematics of the fantastic double pull trigger Diana attached to its various DRP models in the 1930s, the models 27, 35, 45 and 58, followed by pics of an actual trigger block and piston.

First, here is the excellent description of this trigger system Larry Hannusch included in his article on the Dianas 45 (see elsewhere in this section):

It first involves a very unique piston that has a long probe at its tail rather than the traditional piston “bent”. Nearest the piston body at the base of this probe is a conical head that is tapered at the back and straight sided at the front. The trigger block itself pivots up and down on a rear crosspin, and is kept in the downward position by the use of a small compression spring placed at the top front of the trigger block. This trigger block also contains a small, cylindrical wedge within its center. This wedge is cut for trigger sear contact on its belly, and is driven forward by an additional compression spring within the body of the trigger block.

As the lever is pulled back to cock the gun, the piston probe eventually pushes back the wedge against its spring until the trigger sear engages it, thereby cocking the set trigger. As the underlever finishes its cocking stroke, the cone at the base of the piston probe slips past the true sear that is incorporated into the inside front edge of the pivoting trigger block that is being forced downward by the small upper spring. At this point, the piston is held in the rear firing position by the front edge of the pivoting trigger block awaiting the pull of the trigger. As the trigger is pulled, the small wedge flies forward under it’s own spring force, and is driven against the tapered cone of the piston probe. As the small wedge is no match for the solid piston in its path, the wedge’s kinetic energy is deflected upward into the pivoting trigger block, overcoming the downward push of its small upper spring, and the leading sear edge of the trigger block is momentarily driven upward, releasing the piston to fire the gun. There...that was easy!

It is really a brilliant and sturdy design. The trigger itself has two small screw adjustments on it to fine tune the trigger to the shooter’s preference. Without adjusting either setting, I measured the trigger pull, and it breaks crisply and consistently at 2¼ pounds. That is quite impressive for a prewar sporting airgun. As a side note, the gun can be “dry fired” by cocking the underlever until the first click is heard, but before the second click is achieved, and then lowering the lever slowly. When the trigger is pulled, the set trigger is released, giving the same trigger feel as a complete firing. It is a little bit of trouble, and for my time, I’d just as soon complete the full cocking stroke, and leave the tap in the open, upright position to cushion the piston’s sudden stop for dry fire practice.

Some more pics of a model 27 double pull trigger stripped down. With thanks to Rod letting me use these:

Let's not forget the Webley version of Diana's double pull trigger. It was imported to the UK when Webley & Scott copied the 1930s DRP Diana mod 45 as the blueprint for its new successor to the Webley Mk2 Service air rifle, the Webley Mk3, available from about 1947.


   
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Garvin
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MGR detent lever lock - Patent by Jakob Mayer

.

 

With thanks to Peter from http://www.vintageairguns.co.uk/

Original research by the late Dennis Commins.


   
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Garvin
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MGR pistol - Jakob Mayer Patent 1901.

 

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.


   
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Garvin
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Jakob Mayer's famous break-barrel detent 1905.

 

This is the detent that has been widely used for more than a century on break barrel air rifles.

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.


   
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Garvin
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Diana Model-5 air pistol - Patent (rejected) 1932.

 

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.


   
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Garvin
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Diana Model-58 trigger 1915 - Jakob Mayer Patent.

 

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.


   
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Garvin
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M&G Patent for repeating airgun 1895.

 

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.

With thanks to Eberhard for this:

 

Google translation from German:

Data obtained from sources other than the EPO may not be accurate, complete or current.

IMPERIAL

PATENT OFFICE^

The subject of the present invention is an air gun for shooting bullets and bolts at targets and the like.
which differs from the previously used air rifles in that, like them, it can be used both as a single loader and especially as a repeating rifle.

The rifle in Fig. 1 is shown in the accompanying drawing. shown in partial section in use as a single charger.

Fig. 2 shows the same used as a repeating rifle in the loading position, also with a partial section.

Figure 3 is a front view of the barrel.

Fig. 4 shows a bottom view of the mechanism located in the rifle.

Fig. 5 is a top view of the latter.

Figures 6 and 7 are details.

The setup of the repeater is as follows:

A core piece b is screwed into the chamber, in which the plate c shown in FIG. 6 is movably arranged.
The plate c has a small socket c' and is held in place by the latter and by the pins c", one of which is hook-shaped.
led in b. In the extension of the axis of c' the actual barrel / is mounted in b, which is led through the barrel g.
which the latter is closed in front, with the plate.
Above the bullet barrel / is marked b. a plate d connected, which together with the barrel g sucked. Magazine f forms and is designed channel-shaped at its ends.
In its channel b' (Fig. 5) the plate d has a small opening s, which is just large enough for a ball to fall through (Figs. 2 and 5);
at the other end the plate d runs into a tube d', which extends to the muzzle of the barrel g and is attached to the plate.
Through this tube d', which is kept closed by a small spring h (dotted in Fig. 3) rotating about i, the balls are introduced into the magazine f.
Directly below the opening s is a spring-loaded socket r t (Fig. 2 and 4),
which, after the tube c has retreated, receives the ball falling through the opening s through a recess in b (Fig. 2)
and in the process of c' is pushed back into the position shown in dotted lines in FIG.
The going back from . c' or c when the rifle is tilted is caused by the coil springs u arranged around the pins c",
after the hook of one pin c" engaging in a spring e has been released by the pin w shown in detail in FIG. 7 (FIG. 2).

When in use, the overturning rifle is held by the hook \ or other suitable device on the stock k,
which contains the mechanism for generating the necessary air pressure.

The mode of action of the rifle with a single charge, which z. B. must always take place when shooting bolts, is the following:
The small lever n>, which is attached to the outside of the housing, is brought into the position shown in dotted lines in Fig. 1, i.e. pointing to the left.
In this case the spring e lies against the flat of the pin of W^ which protrudes through the housing over the spring e, so that,
as can be seen from Fig., the hook of c'' is kept engaged with e.
Instead of the lever n> mentioned here, another corresponding suitable device can of course also be used.
The repeating mechanism located in can therefore not come into action and the handling of the rifle is the same in this case as before.
If, on the other hand, one wants to use the same air rifle as a repeating rifle, it is only necessary to bring the lever w into the opposite position (as drawn in dotted lines in Fig. 2),
so that the lever on the outside of the housing in the case shown points to the right.
The spring e is pushed back by w and the hook c" is thereby released.
If the rifle is now brought into the loading position shown in Fig. 2 by tilting it,
thus, at the same time, when the mechanism contained in the stock k is cocked, the peculiar repeating mechanism is actuated automatically.

When the hook of c" is released, the spiral springs u can come into action. They push back the disk c or the tube c1.
This opens up the opening s, and one of the balls loaded through the tube d' into the magazine f can
fall through it onto the pan t, which, caused by the spring r, passes through an opening in b into the position shown in Fig. 2.
After the mechanism has been cocked in the shaft k, the rifle is returned to the position of use shown in FIG.
Here, the plate c is pressed back into the housing, the tube c' closes the opening s, forces the socket t down into the position shown in FIG
and pushes the ball into the barrel /, with which the gun is ready for action.
It is easy to see that the manipulation just described should be repeated so often.


   
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Garvin
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Spring loaded detent - Dianawerk M&G Patent 1930.

 

With thanks to Peter from vintageairguns.co.uk.

Original research by the late Dennis Commins.


   
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Garvin
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Tinplate detent lock M&G Patent 1930.

 

Patent 551830. Notice of grant of the patent is dated April 30th 1930.


   
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Garvin
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Diana Model-5 air pistol Patent 1931.

 

Patent no. 574329. Notice of patent granted December 13th 1931

 


   
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Garvin
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Trigger mechanism M&G Patent 1934.

 

Patent no. 653566, October 23rd 1934. This looks like some sort of trigger safety mechanism fitted into the rear of the trigger block.


   
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Garvin
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Double pull trigger M&G Patent 1936.

 

Patent no. 668547, January 10th 1936.


   
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Garvin
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Mayer and Grammelspacher 1901 rifle breech lever lock patent 

With thanks to Steve and John G

 





   
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