# Patent

## Title
Muzzle-loading firearm

## Abstract

A muzzle-loading firearm has a barrel, a frame part, a breech plug, and a firing block arranged adjacent to the rear end of the breech plug, the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug, and an open position in which the firing block does not cover the rear end of the breech plug.

## Background
FIELD OF THE INVENTION
The invention relates generally to muzzle-loading firearms.
BACKGROUND OF THE INVENTION
Because of their classical character, muzzle-loading firearms are popular among sport enthusiasts. For shooting with this kind of firearms, normally, a primer is applied to a rear end of a breech plug inserted in one end of the barrel (the breech end of the barrel), and this primer is used to ignite a powder charge situated inside the barrel, at a front end of said breech plug, whereby front end means the end closest to the muzzle and the rear end the end furthest away from the muzzle.
A problem involved with this kind of firearms is the access to the rear end of the breech plug, which must be accessed in order to insert a primer, to replace a used primer or the withdraw a primer when unloading the firearm. Further, access to the breech plug should preferably be easy in order to allow for easy cleaning of the corresponding parts of the firearm.
Traditionally, access to the breech plug has sometimes required the barrel to be removed, which, of course, may represent an inconvenience.
US-B1-6604311 discloses a lever-operated breech block, which can be pivoted to a removed position in which the user can directly access the breech plug. However, this pivoting mechanism involves a large number of movable parts and interrelated components, which may imply high manufacturing costs and a certain risk for mechanical problems. Thus, one of the objectives of the present invention is to provide for an alternative way of accessing the breach plug or corresponding parts of a firearm. Other objectives of the invention are to provide an improved coupling of the barrel to a body, frame or stock portion or part of the firearm, and to provide an improved block or safety mechanism for preventing accidental detonation of the primer.
Another example of a muzzle-loading firearm is disclosed in my co-pending U.S. patent application Ser. No. 11/051,282, filed Feb. 4, 2005, and entitled“MUZZLE-LOADING FIREARM.”
SUMMARY OF THE INVENTION
The invention relates to a muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel (for example, inserted into said rear end of the barrel, for example, screwed into said rear end of the barrel), said breech plug having a rear end arranged to receive a primer, and a front end (the powder charge is to positioned in correspondence with this front end, so as to be ignited by the primer, through a channel or similar provided in the breech plug);
a frame part arranged in correspondence with the rear end of the breach plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged so that it can be displaced between a front position (in which, when the firearm is in use, it actuates on the primer, causing it to detonate and thus to ignite the powder charge) and a rear position in said firing pin channel (where the firing pin is withdrawn with regard to the primer).
The firing block is slidably connected to the frame part so that said firing block can slide rectilinearly (or at least substantially rectilinearly, and not in a pivoting manner as per the invention disclosed in my aforementioned U.S. patent application Ser. No. 11/051,282, the full disclosure of which is incorporated herein by reference), in a direction substantially perpendicular to a longitudinal axis of the barrel (for example, “downwards” and “upwards” when the firearm is in a position corresponding to the normal position of “use” of this kind of firearm), between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug (and with the primer, when the primer has been attached to the rear end of the breech plug), and an open position in which the firing block does not cover the rear end of the breech plug. In this open position, the user can access the breech plug, for example, in order to insert a new primer and/or to remove a used primer. Thus, access to the breech plug is provided without any need for tilting the firing mechanism including hammer and trigger, etc. That is, the present invention provides for an extremely simple and reliable means for accessing the breech plug.
The firing block can be arranged so that said closed position corresponds to an upper position and so that said open position corresponds to a lower position of the firing block, when the firearm is arranged with the longitudinal axis of the barrel arranged horizontally and with the trigger generally directed downwards.
The firing block can comprises at least one leg member slidably connected to the frame part so as to make the firing block slidable with regard to said frame part. Said at least one leg member can comprise two leg members slidably connected to the frame part so as to make the firing block slidable with regard to said frame part.
The firearm can further comprise a pivotally arranged blocking element arranged so as to selectively block the firing block in its closed position and/or in its open position. Said blocking element can be biased towards a blocking position by a spring element.
Said blocking element can comprise an end portion arranged to be inserted in at least one corresponding recess in the firing block so as to block the firing block from sliding. Said at least one recess in the firing block can comprise a recess in a leg member of the firing block (which can serve to block the firing block from moving downwards when the firing block is in its closed position, with a corresponding portion of the blocking element inserted into said recess). Said at least one recess in the firing block can further comprise a recess below an upper step portion of the firing block (which can prevent the firing block from moving further downwards when the firing block is in its open position, as said upper step portion will then abut against a corresponding portion of the blocking element).
Said blocking element can comprise a push surface arranged so that the user can exert a force against said push surface so as to pivot the blocking element against a force exerted by a spring element that biases the blocking element towards a blocking position, so as to bring the blocking element to a non-blocking position in which the blocking element does not prevent the firing block from sliding between its open and its closed position.
The firing block can be provided with a projecting portion for facilitating sliding of the firing block from its closed to its open position.
The firing block can comprise a rear opening defining a channel or recess (which can have a dove-tail shaped cross section) for inserting, by sliding (for example, from below), a disc element having a bevelled circumference, so as to retain said disc element, said firing block further comprising a disc element having a bevelled circumference inserted and retained in said channel, whereby the firing pin has a rear portion abutting against said disc element. Thus, this disk element serves to retain the firing pin in the firing block, and it can be removed by simply pushing the disc element forwards, against the force exerted by the firing pin, and downwards, sliding along the channel. Thereby, the disk element and the firing pin can be easily removed from and re-inserted into the firing block, for example, in connection with cleaning operations.
The firearm can further comprise an element made up of one single plastic piece that constitutes a barrel-protector and a butt of the firearm. The use of such a single piece element, instead of separate elements making up barrel-protector and butt, can further reduce the manufacturing costs. The frame part can be attached to said one single plastic piece that constitutes a barrel-protector and a butt of the firearm; for example, it can be slid or form-fitted into a corresponding portion or recess of that plastic piece. The frame part can be fixed to said single plastic piece by means of at least one screw.
The frame part can be of metal. With the structure described above, a single plastic piece can be used for barrel-protector and butt, and the metal frame part can be made very small, thus further reducing the cost of the product.
The firearm can further comprise a pivotally arranged hammer arranged to pivot between a rear position in which a contact portion of said hammer is withdrawn or retracted with regard to the firing pin, and a fire position in which said contact portion contacts the firing pin so as to push it against the primer. A rear end of the firing block can comprises a disc element, and the firing pin can have a wider portion arranged to be biased against said disc element by means of a firing pin spring, and further a rear portion thinner than said wider portion. The disc element can comprise a through hole dimensioned to receive said rear portion, and the contact portion of the hammer can be dimensioned and arranged so as to enter the through hole when the hammer is in the fire position, so as to push the firing pin against its front position in order to actuate on the primer.
The firearm can further comprise a first hammer spring arranged to push the hammer from the rear position towards the fire position, and a second hammer spring arranged to push the hammer rearwards from the fire position. That is, the two springs exert opposed forces on the hammer. The first hammer spring can be arranged to exert pressure on the hammer so as to force the hammer towards the fire position during a first portion of movement of the hammer from the rear position to the fire position, and not to exert such pressure on the hammer during a last portion of said movement of the hammer from the rear position to the fire position; for this purpose, the first hammer spring can be arranged to be prevented from following the hammer to the fire position by a first hammer spring retention means. In this way, it can be achieved that the hammer moves by inertia during the last portion of the movement towards the fire position, against the force exerted by the second hammer spring. Thereby, it can be achieved that the second hammer spring can, once the hammer (due to inertia of the movement initially caused by the force exerted by the first hammer spring) has reached and displaced the firing pin, force the hammer to return to a “neutral” position, between the rear position and the fire position. In this neutral position, the forces exerted by the first and second hammer springs are balanced, so that the hammer tends to remain in said neutral position.
The first hammer spring and the second hammer spring can thus be selected and arranged so that after firing the firearm, the hammer is moved rearwards from the fire position by the second hammer spring, to said neutral position.
The firearm can further comprise a pivotally arranged trigger biased against a hammer blocking position and pivotable between said hammer blocking position and a hammer releasing position, the trigger having a hammer contact portion arranged so that when the trigger is in the hammer blocking position, said hammer contact portion can, depending on the position of the hammer, selectively abut against a first retention configuration of the hammer, so as to keep the hammer in the rear position, or against a second retention configuration of the hammer, so as to prevent the hammer from passing from a neutral position, in which the hammer is substantially balanced by the first hammer spring and the second hammer spring, to the fire position.
The first retention configuration can be shaped so as to allow the hammer contact portion to be displaced from a first position (corresponding to the hammer blocking position of the trigger), in which the hammer contact portion abuts against said first retention configuration, to a second position (corresponding to the hammer releasing position of the trigger), in which it does not abut against said first retention configuration thus allowing the hammer to pass from the rear position to the fire position, by means of pulling the trigger so as to displace it from its hammer blocking position to its hammer releasing position.
The second retention configuration can be substantially hook-shaped, for receiving the hammer contact portion if the hammer is urged towards the fire position without the trigger being pulled.
The trigger can be biased against the hammer blocking position by said first hammer spring.
The firearm can further comprise a blocking pin displaceable between a trigger blocking position, in which the pin prevents the trigger from moving to the hammer releasing position, and a trigger releasing position, in which it does not prevent the trigger from moving to the hammer releasing position. For this purpose, the trigger blocking pin can be provided with a recess for receiving a blocking profile of the trigger when the blocking pin is in the trigger releasing position.
The trigger, the hammer, the first hammer spring and the second hammer spring can all be arranged in a removable cassette, so that these parts can be jointly removed with the cassette, for example, in connection with cleaning of the firearm.
The barrel can be provided with a projection arranged for guiding the barrel in a guide groove in the frame part or in the barrel-protector, when mounting the barrel to the frame part or barrel-protector, respectively. Said projection can comprise a substantially prismatic body fixed (for example, welded) to the barrel. The projection can comprise at least two threaded holes for receiving respective screws (such as Allen screws) by means of which the barrel can be fastened to the frame part or barrel-protector. The barrel can further be provided with a further projection including a threaded hole for receiving a screw by means of which a barrel-protector can be (further) fastened to the barrel; this barrel-protector can serve to allow the user to support the firearm during use, without having the grip the barrel directly.



BRIEF DESCRIPTION OF THE DRAWINGS
To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate a preferred embodiment of the invention, which should not be interpreted as restricting the scope of the invention, but just as an example of how the invention can be embodied. The drawings comprise the following figures:
FIG. 1 is a vertical right side elevational view of a partial longitudinal cross section of the firearm according to a preferred embodiment of the invention (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282,), with the hammer in the fire position.
FIG. 2 is a view similar to FIG. 1 but with the hammer forced forward but blocked by a safety arrangement (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 3 is a view similar to FIG. 1 but with the hammer in a neutral position (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 4 is a view similar to FIG. 1 but with the hammer in a rear or retracted position, prior to pulling of the trigger (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 5 is a vertical right side elevational view of the firearm (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 6 is a view similar to FIG. 5 but with the barrel dismounted (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 7 is a view similar to FIG. 6 but with the firearm partly dismounted (but with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282).
FIG. 8A is a vertical rear elevational cross section of the firearm, schematically showing the firing block disclosed in U.S. patent application Ser. No. 11/051,282 in the open position.
FIG. 8B is a view similar to FIG. 8A but with the firing block disclosed in U.S. patent application Ser. No. 11/051,282 in its closed position.
FIG. 9 is an exploded view of the firearm (with a firing block, frame part and barrel-protector as disclosed in U.S. patent application Ser. No. 11/051,282), showing some of its components.
FIGS. 10 and 11 are vertical right side elevational views of a partial longitudinal cross section of the firearm according to a preferred embodiment of the invention, with the firing block in accordance with the invention in the closed and in the open position, respectively.
FIG. 12A is a vertical rear elevational cross section of the firearm, schematically showing the firing block in accordance with an embodiment of the invention, in the closed position.
FIG. 12B is vertical left side elevational view of a partial longitudinal cross section of the firearm, showing the firing block in accordance with this embodiment of the invention, in the closed position.
FIG. 13A is a vertical rear elevational cross section of the firearm, schematically showing the firing block in accordance with this embodiment of the invention, in the open position.
FIG. 13B is vertical left side elevational view of a partial longitudinal cross section of the firearm, showing the firing block in accordance with this embodiment of the invention, in the open position.
FIG. 14 is a vertical right side elevational view of a longitudinal cross section of the single plastic piece constituting barrel-protector and butt of the firearm in accordance with an embodiment of the invention.



DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
FIG. 9 shows an exploded view of the firearm in accordance with one possible embodiment of the present invention (but featuring a firing block, barrel-protector and frame part as disclosed in U.S. patent application Ser. No. 11/051,282; however, the rest of the illustrated firearm are directly applicable to the present invention, whereby only the firing block and, optionally, the frame part and the barrel-protector and butt arrangement need to be adapted as shown in FIGS. 10-13B). The barrel 1 has a front or muzzle end and a rear end arranged to be received by a frame part 3 (or directly by a barrel-protector 131 forming part of a single piece 100 made of plastic, such as suggested in FIGS. 10, 11 and 14). A breech plug 4 is arranged to be screwed into the rear end of the barrel. The breech plug has a rear end arranged to receive a primer 5 (cf., for example, FIG. 1) and a front end, against which the powder charge is applied when the firearm is loaded through the muzzle end of the barrel. The barrel is provided with conventional aiming means and other conventional accessories, well-known to the skilled person and that do not need to be further discussed herein.
A substantially prismatic body 6 is welded to the rear end of the barrel and is designed to fit into a guide groove 3b in the frame part 3 (or into a corresponding groove of the barrel-protector 131, in the embodiment shown in FIGS. 10 and 11). Thus, when mounting the barrel 1 to the frame part 3 (or barrel-protector 131), said prismatic body 6 is inserted into the groove 3b (or an equivalent groove in the barrel-protector 131), whereby it acts as a guiding means for the barrel, sliding along the groove until a rear end 6a (cf. FIG. 1) of said prismatic body 6 abuts against a corresponding support surface of the frame part. Thus, the prismatic body 6 allows for a correct and stable positioning of the barrel with respect to the frame part. Once in its correct position, the barrel is fastened to the frame part by means of two Allen screws 2 which are inserted into respective threaded holes 6b in the prismatic body 6.
A barrel-protector 31 (or the barrel-protector 131 forming part of the single piece 100) is attached to the barrel by a screw 8 inserted into a threaded hole in a projection 7 from the barrel. The firearm further comprises a ramrod 29 arranged to be housed under the barrel, within the housing constituted by the barrel-protector. A ramrod retention spring 30 is provided to exert pressure on the ramrod when inserted under the barrel, to prevent it from being accidentally removed.
A conventional butt 32 is attached to a rear end of the frame part 3 (or, as illustrated in FIGS. 10, 11 and 14, a butt 132 can be used that forms part of the same piece 100 that constitutes the barrel-protector).
In FIG. 9, a firing block 9 is arranged adjacent to the rear end of the breech plug 4. The firing block 9, of the type disclosed in U.S. patent application Ser. No. 11/051,282 (although it can be replace by a firing block 109 as described below), houses a firing pin 12 in a longitudinal firing pin channel of said firing block 9, whereby the firing pin 12 is arranged so that it can be displaced between a front position (in which it actuates on a primer 5 inserted into the breech plug, as shown in FIG. 1) and a rear position (shown in, for example, FIG. 2) in said firing pin channel.
A rear end of the firing block 9 is provided with a disc element 14 closing the firing pin channel at its rear end. The firing pin 12 has a wider portion 12a arranged to be biased against said disc element 14 by means of a firing pin spring 13. The firing pin 12 further has a rear portion 12b thinner than said wider portion 12a. The disc element 14 comprises a through hole 14a dimensioned so that said rear portion 12b can enter said through hole 14a, while said wider portion cannot enter said through hole. Thus, when the hammer 17 is not acting on the firing pin 12, the firing pin 12 is in its rear position, biased by the firing pin spring 13, the rear end of the wider portion abutting against the disc element 14. The disc element is attached to the firing block 9 by means of a screw 15. The hammer is provided with a contact portion 17a dimensioned and arranged so as to enter the through hole 14a when the hammer is in its fire position (see below), thus pushing the firing pin against its front position, that is, from the position shown in FIG. 2 to the position shown in FIG. 1. What has been stated concerning disk element 14 is also applicable to disk element 113 discussed below, mutatis mutandis.
In the specific embodiment shown in FIG. 9, the firing block 9 is pivotally connected to the frame part 3 such as to be pivotable in a plane perpendicular to barrel 1, between a closed position (shown in FIG. 8B) in which the firing block 9 covers the rear end of the breech plug 4 (with the firing pin channel aligned with said breech plug), and an open position (shown in FIG. 8A) in which the firing block 9 does not cover the rear end of the breech plug, thus allowing access to the breech plug, for example, in order to insert or remove the primer 5.
The firing block 9 is pivotally arranged around a shaft pin 10 (cf. FIGS. 1, 7, 8A and 8B) extending in a direction parallel with the barrel 1. The shaft pin 10 is provided with a radial flange 10b for facilitating manual removal of said shaft pin (without any need for any specific tool) and with a conical front end 10a for facilitating insertion of the shaft pin 10 in a corresponding shaft pin channel (not shown in the drawings) in the frame part and in the firing block.
A front portion of the firing block 9 is provided with a recess 9a arranged to receive a tip of a locking pin 11 when the firing block 9 is in its closed position. The locking pin 11 is biased into said recess 9a by a locking pin spring 11a. The recess 9a has a sloped or bevelled side wall which makes it possible to force the locking pin to move backwards against the force of the locking pin spring 11a, by means of manually forcing the firing block 9 to pivot towards its open position.
The firing block 9 is provided with a projecting portion 9b for facilitating manual tilting of the firing block 9 from its closed to its open position, including overcoming the force exerted by the locking pin spring 11a. 
In an alternative embodiment, the firearm includes a firing block as illustrated in FIGS. 10-13B. Parts identical to those discussed in connection with FIGS. 1-9 bear the same reference numerals and need not be further discussed. Now, in the preferred embodiment illustrated in FIGS. 10-13B, the firearm is provided with a frame part 103 of rather small dimensions, coupled to the butt by means of a screw 19. The frame part 103 can be made up of, for example, ZAMAC or aluminium. The frame part 103 can directly replace the frame part 3 discussed in other parts of this description, with a suitable adaptation of the barrel-protector and, if appropriate, butt.
Now, as shown in FIGS. 10-13B, the firing block 109 in accordance with the invention is slidably connected to the frame part 103 so that said firing block can slide substantially linearly in a direction substantially perpendicular to a longitudinal axis of the barrel 1, between a closed position in which the firing block covers the rear end of the breech plug 4 with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug 4. Said closed position corresponds to an upper position and said open position corresponds to a lower position of the firing block 109, when the firearm is arranged with the longitudinal axis of the barrel arranged horizontally and with the trigger generally directed downwards, as shown in the drawings. The firing block comprises two leg members 109A slidably connected to the frame part 103 so as to make the firing block 109 slidable with regard to said frame part.
The firearm further comprises a pivotally arranged blocking element 105 (cf. FIGS. 12A-13B) mounted to pivot around a pin 111 and arranged so as to selectively block the firing block 109 in its closed position (FIGS. 12A and 12B) and in its open position (FIGS. 13A and 13B). The blocking element is biased towards a blocking position by a spring element 112, and comprises an end portion 106 arranged to be inserted in at least one corresponding recess (109C, 109D) in the leg elements 109A of the firing block, so as to block the firing block from sliding. One of said recesses 109C is located in a leg member 109A of the firing block (by means of this recess, the firing block can be blocked in its closed position), and another one corresponds to a recess 109D below an upper step portion of the firing block. The blocking element 105 further comprises a push surface 105A arranged so that the user can exert a force against said push surface so as to pivot the blocking element against a force exerted by the spring element 112 that biases the blocking element towards a blocking position, so as to bring the blocking element to a non-blocking position in which it does not prevent the firing block from sliding from its open to its closed position.
The firing block is provided with a projecting portion 109B, which can easily be engaged by the user, for facilitating sliding of the firing block from its closed towards its open position.
Further, the firing block 109 comprises a rear opening 114 defining a channel for inserting, by sliding, a disc element 113 having a bevelled circumference, said firing block further comprising said disc element 113 with bevelled circumference inserted in said channel (said channel thus featuring a dove-tailed configuration, as shown in FIGS. 10 and 11, for example), whereby the firing pin 12 has a rear portion abutting against said disc element as described above. Thus, by pushing the disc element (which can be some kind of bevelled washer) forwards (against the force exerted by the spring 13 pushing the firing pin backwards) and downwards, the disc element can be removed, thus allowing withdrawal of the firing pin. This arrangement makes it easy to remove the firing pin, and thus facilitates disassembly and cleaning of the relevant parts of the firearm. In the same manner, assembly of the parts is easy: in order to retain the firing pin, it is pushed forwards against the force of the spring 13 (cf. FIG. 9), whereafter the disc element 113 is slid into the channel defined by the opening, its bevelled circumference fitting into the dove-shaped channel.
FIG. 14 illustrates how the firearm, in accordance with one embodiment of the invention, comprises an element 100 made up of one single plastic piece (which can be moulded in one single operation of injection moulding) that constitutes both the barrel-protector 131 and the butt 132 of the firearm. The frame part 103 is attached to said one single plastic piece 100, slid into a corresponding portion or recess and fixed in its position by a screw 103a. 
The firearm further comprises a pivotally arranged hammer 17 arranged to pivot (around a hammer pivot pin 21) between a retracted or rear position in which the above-mentioned contact portion 17a of said hammer is withdrawn with regard to the firing pin 12, and a fire position in which said contact portion 17a enters into the through hole 14a in the disc 14 and thus contacts the firing pin, forcing it to move against the biasing force exerted by the firing pin spring 13. Two springs are provided for controlling the movement of the hammer, namely, a first hammer spring 23 arranged to push the hammer 17 from the rear position towards the fire position, and a second hammer spring 24 arranged to push the hammer rearwards from the fire position. The first hammer spring 23 is arranged to exert pressure on the hammer 17 so as to force the hammer towards the fire position only during a first portion of movement of the hammer from the rear position to the fire position (namely, during the portion corresponding to the movement of the hammer from the position shown in FIG. 4 to the position shown in FIG. 3), and not to exert such pressure on the hammer during a last portion of said movement of the hammer (namely, from the position shown in FIG. 3 to the position shown in FIG. 1) from the rear position to the fire position.
This is achieved by a first hammer spring retention means 3a (cf. FIG. 1) consisting in a flange or similar means provided for inside the frame part 3 (or 103), and arranged so that once the hammer reaches a “neutral” position between said rear position and said fire position, an end of the first hammer spring 23 abuts against said retention means 3a, whereby it is prevented from “following” the hammer. The rest of the movement of the hammer against its fire position (shown in FIG. 1) takes place due to the inertia of the hammer, and against the force exerted by the second hammer spring (which thus must be selected so as not to provide a force that would impede the hammer from reaching the fire position due to its inertia).
The firearm further comprises a trigger 18 biased (by the first hammer spring 23) towards a hammer blocking position and pivotable (around a trigger pivot pin 22) between said hammer blocking position and a hammer releasing position. The trigger has a hammer contact portion 18a arranged so that when the trigger is in the hammer blocking position, said hammer contact portion 18a can, depending on the position of the hammer, selectively abut against a first retention configuration 17b of the hammer, so as to keep the hammer in the rear position, or against a second retention configuration 17c of the hammer, so as to prevent the hammer 17 from passing from a neutral position (cf. FIG. 3), in which the hammer is substantially balanced by the first hammer spring 23 and the second hammer spring 24, to the fire position.
The first hammer spring 23 and the second hammer spring 24 are selected and arranged so that after firing the firearm, the hammer is moved rearwards from the fire position by the second hammer spring 24, to said neutral position.
The first retention configuration 17b is shaped so that the hammer contact portion 18a can be displaced from a first position, in which the hammer contact portion 18a abuts against said first retention configuration 17b, to a second position, in which it does not abut against said first retention configuration 17b thus allowing the hammer to pass from the rear position to the fire position, by means of pulling the trigger 18, thus displacing the trigger from its hammer blocking position to its hammer releasing position.
The second retention configuration 17c is substantially hook-shaped for receiving the hammer contact portion 18a in case of the hammer being urged towards the fire position without the trigger being pulled. After firing the firearm, the second hammer spring 24 forces the hammer backwards, towards its neutral position, that is, to the position where it is balanced by the two hammer springs. In that position, the hammer contact portion 18a of the trigger 18 will be positioned immediately behind the “hook” of the second retention configuration, as shown in FIG. 3.
The firearm further comprises a blocking pin 25 displaceable between a trigger blocking position, in which the pin prevents the trigger from moving to the hammer releasing position, and a trigger releasing position, in which it does not prevent the trigger from moving to the hammer releasing position. The trigger blocking pin 25 is provided with a recess 25a for receiving a blocking profile 18b of the trigger when the blocking pin is in the trigger releasing position. Thus, the trigger can only be pulled so as to fire the firearm when the trigger blocking pin 25 is in its trigger releasing position. The trigger blocking pin is provided with bevelled surfaces arranged to cooperate with a pin 26. A spring 27, supported by another pin 28, biases the pin 26 against the trigger blocking pin. The trigger blocking pin 25 is shaped so that the interaction between its bevelled surfaces and the pin 26 causes the trigger blocking pin 25 two be substantially stable in the trigger releasing position and in the trigger blocking position, so that a certain minimum force must be exerted on the trigger blocking pin to move it from one of said positions to the other, and whereby a “click” effect is achieved when the trigger blocking pin 25 enters into any of said positions.
The trigger 18, the hammer 17, the first hammer spring 23, the second hammer spring 24 and the trigger blocking pin 25 are arranged in a cassette 16 (which can further comprise the triggerguard). The cassette, when in its mounted position (that is, when mounted to the firearm so that the firearm is ready to be used), is supported at its front end by a pin 20 fitting into a notch arranged at said front end of the cassette. A screw 19 arranged at the rear end of the cassette is used for locking the cassette in said mounted position. By removing the screw, the cassette can be separated from the rest of the firearm, whereby the user can access several parts of the firearm, for example, for cleaning them.
The trigger arrangement described above is also used in the embodiment shown in FIGS. 10 and 11, although adapted to cooperate with frame part 103, barrel-protector 131 and butt 132, as illustrated in FIGS. 10 and 11.
FIG. 7 schematically illustrates the firearm according to one embodiment of the invention dismounted into some of its major components or groups of components, namely, the frame part 3 (including the butt 32), the barrel 1 (attached to the barrel-protector 31) (butt and barrel-protector could be made up of one single piece, as suggested in FIG. 14), the firing block 9 (which could be replaced by firing block 109 as described above), and the cassette 16 with the trigger 18 and hammer 17. In FIG. 6, the cassette 16 and the firing block 9 have been attached to the frame part 3 (in an alternative embodiment described herein, the cassette is attached to the barrel-protector 131, cf. FIGS. 10 and 11). In FIG. 5, the barrel has been attached to the frame part, by means of sliding the projection 6 along the guide groove 3b in the frame part 3, until the rear end 6a of the projection abuts against the frame part (in FIGS. 10 and 11, the barrel is attached to the barrel-protector 131 in a similar manner).
Now, when using the firearm, the following sequence can be followed:
(1) First, the hammer 17 is manually retracted to its rear position, illustrated in FIG. 4. In this position, the contact portion 17a is withdrawn with regard to the firing pin 12. The firing pin is biased against the disc 14, the rear portion 12b being housed in the through hole 14a of said disc (the same applies when the disk element 113 with bevelled circumference disclosed herein is used).
The hammer is retained in its rear position by means of the hammer contact portion 18a of the trigger 18, which abuts against the first retention configuration 17b of the hammer. The trigger is in its hammer blocking position, towards which it is biased by the first hammer spring 23.
In order to fire the firearm, the trigger must be displaced to the trigger releasing position. This requires the trigger blocking pin 25 to be in its trigger releasing position, so that the trigger blocking profile can enter the corresponding recess 25a in the trigger blocking pin, thus allowing the trigger to be pulled backwards, against the force exerted by the first hammer spring, to the hammer releasing position of the trigger 18, in which the hammer contact portion 18a of the trigger no longer abuts against the first retention configuration of the hammer.
(2) When the trigger reaches its hammer releasing position, the hammer contact portion 18a of the trigger no longer prevents the hammer 17 from leaving its rear position. Thus, due to the force exerted on the hammer by the first hammer spring 23, the hammer is forced to move forwards (against the substantially weaker force exerted by the second hammer spring), towards the position in which the hammer contacts the firing pin. However, before contacting the firing pin, the hammer reaches a position, shown in FIG. 3, in which an end of the first hammer spring 23 contacts the first hammer spring retention means 3a (such as a flange or similar surface configuration corresponding to the frame part), whereby the first hammer spring 23 ceases to exert its force on the hammer 17.
(3) However, due to its inertia and due to the comparatively weak force exerted by the second hammer spring 24, the hammer continues to move towards the firing pin, until the hammer contact portion reaches and enters the through hole 14a, pushing the firing pin 12 towards its front position, wherein the firing pin actuates on the primer 5, in the position illustrated in FIG. 1. The primer is thus activated and ignites the powder charge situated at the opposite end of the breech plug 4.
(4) However, immediately after having pushed the firing pin 12, the hammer is displaced in the opposite direction, “backwards”, due to the force exerted by the second hammer spring 24, until the hammer reaches its neutral position, substantially as in FIG. 3, with the hammer being “balanced” by the first 23 and second 24 hammer springs. Now, in this position, the hammer contact portion 18a of the trigger is situated slightly behind the hook-shaped second retention configuration 17c. 
(5) With the hammer in this neutral position, and assuming that the hammer is accidentally forced to move “forwards” towards the firing pin, it will reach the position illustrated in FIG. 2. In this position, the hammer 17 is prevented from continuing its movement against the firing pin as the hammer contact portion 18a of the trigger cooperates with the second retention configuration 17c. Also, in this position, it is impossible to pull the trigger, as the hook-shaped second retention configuration prevents the trigger from pivoting.
In this text, the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.
On the other hand, the invention is obviously not limited to the specific embodiment(s) described herein, but also encompasses any variations that may be considered by any person skilled in the art (for example, as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention as defined in the claims.
Some features of the invention have only been described in connection with one embodiement; however, they are obviously also applicable to other embodiments of the invention.
LIST OF THE REFERENCE NUMERALS USED IN THE DRAWINGS
1 barrel
2 screws
3 frame part
3a hammer spring retention means
3b guide groove in frame part, for receiving projection at rear end of barrel
4 breech plug
5 primer
projection (in the form of a substantially prismatic body) welded to the barrel, for guiding the barrel in the frame part and for fastening the barrel to the frame part
6a rear end of the projection (prismatic body)
6b threaded holes
7 projection for fastening the barrel to the barrel-protector
8 screw
9 firing block
9a recess in firing block
9b projecting portion of the firing block
10 shaft pin
10a conical front end of shaft pin
10b flange portion of shaft pin
11 locking pin
11a locking pin spring, for biasing the locking pin into the recess 9a 
12 firing pin
12a wider portion of firing pin
12b rear portion of firing pin
13 firing pin spring
14 disc element
14a through hole in disc element, for receiving the rear portion of the firing pin and the contact portion of the hammer
15 screw
16 cassette
17 hammer
17a contact portion of the hammer, arranged to act on the firing pin
17b first retention configuration
17c second retention configuration
18 trigger
18a hammer contact portion
18b trigger blocking profile
19 screw
20 pin supporting the cassette
21 hammer pivot pin
22 trigger pivot pin
23 first hammer spring
24 second hammer spring
25 trigger blocking pin
25a recess in trigger blocking pin
26 pin
27 spring
28 pin
29 ramrod
30 ramrod retention spring
31 barrel-protector
32 butt
100 single plastic piece making up barrel-protector and butt
103 frame part in accordance with an alternative embodiment
103a screw
105 pivotally arranged blocking element
105A push surface
106 end portion of pivotally arranged blocking element
109 firing block in accordance with a preferred embodiment of the invention
109A leg members of the firing block
109B projecting portion of the firing block
109C recess in leg member of firing block
109D recess below upper step portion of firing block
111 pin
112 spring element
113 disc element having a bevelled circumference
114 housing for bevelled disc element
131 barrel-protector
132 butt

## Claims

1. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug; and
a pivotally arranged blocking element arranged so as to selectively block the firing block in its closed position and in its open position, wherein said blocking element comprises an end portion arranged to be inserted in at least one corresponding recess in the firing block so as to block the firing block from sliding, and wherein said at least one recess in the firing block comprises a recess in a leg member of the firing block.

2. The firearm according to claim 1, wherein the firing block is arranged so that said closed position corresponds to an upper position and so that said open position corresponds to a lower position of the firing block, when the firearm is arranged with the longitudinal axis of the barrel arranged horizontally and with the trigger generally directed downwards.

3. The firearm according to claim 1, wherein the firing block comprises at least one leg member slidably connected to the frame part so as to make the firing block slidable with regard to said frame part.

4. The firearm according to claim 3, wherein said at least one leg member comprises two leg members slidably connected to the frame part so as to make the firing block slidable with regard to said frame part.

5. The firearm according to claim 1, wherein said blocking element is biased towards a blocking position by a spring element.

6. The firearm according to claim 1, wherein said at least one recess in the firing block further comprises a recess below an upper step portion of the firing block.

7. The firearm according to claim 6, wherein said blocking element comprises a push surface arranged so that the user can exert a force against said push surface so as to pivot the blocking element against a force exerted by a spring element that biases the blocking element towards a blocking position, so as to bring the blocking element to a non-blocking position in which it does not prevent the firing block from sliding between its open and its closed position.

8. The firearm according to claim 1, wherein the firing block is provided with a projecting portion for facilitating sliding of the firing block from its closed towards its open position.

9. The firearm according to claim 1, wherein the firearm further comprises an element made up of one single plastic piece that constitutes a barrel-protector and a butt of the firearm.

10. The firearm according to claim 9, wherein the frame part is attached to said one single plastic piece that constitutes a barrel-protector and a butt of the firearm.

11. The firearm according to claim 10, wherein said frame part is fixed to said single plastic piece that constitutes a barrel-protector and a butt of the firearm by means of at least one screw.

12. The firearm according to claim 10, wherein said frame part is of metal.

13. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug; and
wherein the firing block comprises a rear opening defining a channel having a dove-tail shaped cross section for inserting, by sliding, a disc element having a bevelled circumference, said firing block further comprising a disc element with bevelled circumference inserted in said channel, whereby the firing pin has a rear portion abutting against said disc element.

14. The firearm according to claim 13, wherein the firing block is arranged so that said closed position corresponds to an upper position and so that said open position corresponds to a lower position of the firing block, when the firearm is arranged with the longitudinal axis of the barrel arranged horizontally and with the trigger generally directed downwards.

15. The firearm according to claim 13, wherein the firing block comprises at least one leg member slidably connected to the frame part so as to make the firing block slidable with regard to said frame part.

16. The firearm according to claim 15, wherein said at least one leg member comprises two leg members slidably connected to the frame part so as to make the firing block slidable with regard to said frame part.

17. The firearm according to claim 13, wherein said blocking element is biased towards a blocking position by a spring element.

18. The firearm according to claim 13, wherein the firing block is provided with a projecting portion for facilitating sliding of the firing block from its closed towards its open position.

19. The firearm according to claim 13, wherein the firearm further comprises an element made up of one single plastic piece that constitutes a barrel-protector and a butt of the firearm.

20. The firearm according to claim 19, wherein the frame part is attached to said one single plastic piece that constitutes a barrel-protector and a butt of the firearm.

21. The firearm according to claim 20, wherein said frame part is fixed to said single plastic piece that constitutes a barrel-protector and a butt of the firearm by means of at least one screw.

22. The firearm according to claim 20, wherein said frame part is of metal.

23. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug; and
a pivotally arranged hammer arranged to pivot between a rear position in which a contact portion of said hammer is withdrawn with regard to the firing pin, and a fire position in which said contact portion contacts the firing pin;
wherein a rear end of the firing block comprises a disc element, the firing pin having a wider portion arranged to be biased against said disc element by means of a firing pin spring, the firing pin further having a rear portion thinner than said wider portion, the disc element comprising a through hole dimensioned to receive said rear portion, the contact portion of the hammer being dimensioned and arranged so as to enter the through hole when the hammer is in the fire position, so as to push the firing pin against its front position.

24. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug;
a pivotally arranged hammer arranged to pivot between a rear position in which a contact portion of said hammer is withdrawn with regard to the firing pin, and a fire position in which said contact portion contacts the firing pin; and
a first hammer spring arranged to push the hammer from the rear position towards the fire position, and a second hammer spring arranged to push the hammer rearwards from the fire position towards the rear position, the first hammer spring being arranged to exert pressure on the hammer so as to force the hammer towards the fire position during a first portion of movement of the hammer from the rear position to the fire position, and not to exert such pressure on the hammer during a last portion of said movement of the hammer from the rear position to the fire position.

25. The firearm according to claim 24, wherein the first hammer spring is arranged to be prevented from following the hammer to the fire position by a first hammer spring retention means.

26. The firearm according to claim 25, wherein the first hammer spring and the second hammer spring are selected and arranged so that after firing the firearm, the hammer is moved rearwards from the fire position by the second hammer spring, to a neutral position.

27. The firearm according to claim 24, further comprising a pivotally arranged trigger biased against a hammer blocking position and pivotable between said hammer blocking position and a hammer releasing position, the trigger having a hammer contact portion arranged so that when the trigger is in the hammer blocking position, said hammer contact portion can, depending on the position of the hammer, selectively abut against a first retention configuration of the hammer, so as to keep the hammer in the rear position, or against a second retention configuration of the hammer, so as to prevent the hammer from passing from a neutral position, in which the hammer is substantially balanced by the first hammer spring and the second hammer spring, to the fire position.

28. The firearm according to claim 27, wherein the first retention configuration is shaped so that the hammer contact portion can be displaced from a first position, in which the hammer contact portion abuts against said first retention configuration, to a second position, in which it not abuts against said first retention configuration thus allowing the hammer to pass from the rear position to the fire position, by means of pulling the trigger so as to displace it from its hammer blocking position to its hammer releasing position.

29. The firearm according to claim 27, wherein the second retention configuration is substantially hook-shaped for receiving the hammer contact portion in case of the hammer being urged from the neutral position towards the fire position, without the trigger being pulled.

30. The firearm according to claim 27, wherein the trigger is biased against the hammer blocking position by said first hammer spring.

31. The firearm according to claim 27, further comprising a blocking pin displaceable between a trigger blocking position, in which the pin prevents the trigger from moving to the hammer releasing position, and a trigger releasing position, in which it does not prevent the trigger from moving to the hammer releasing position.

32. The firearm according to claim 31, wherein the trigger blocking pin is provided with a recess for receiving a blocking profile of the trigger when the blocking pin is in the trigger releasing position.

33. The firearm according to claim 27, wherein the trigger, the hammer, the first hammer spring and the second hammer spring are arranged in a removable cassette.

34. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug;
whereby the barrel is provided with a projection arranged for guiding the barrel in a guide groove in a barrel-protector of the firearm, when mounting the barrel to the barrel-protector, said projection comprising a substantially prismatic body fixed to the barrel; and
wherein the projection comprises at least two threaded holes for receiving respective screws by means of which the barrel is fastened to the barrel-protector.

35. The firearm according to claim 34, wherein the barrel is provided with a further projection including a threaded hole for receiving a screw by means of which the barrel-protector is further fastened to the barrel.

36. A muzzle-loading firearm comprising:
a barrel having a front end corresponding to a muzzle of the barrel, and a rear end;
a breech plug arranged at the rear end of the barrel, said breech plug having a rear end arranged to receive a primer, and a front end;
a frame part arranged in correspondence with the rear end of the breech plug;
a firing block arranged adjacent to the rear end of the breech plug, said firing block housing a firing pin in a longitudinal firing pin channel of said firing block, whereby the firing pin is arranged displaceable between a front position and a rear position in said firing pin channel;
the firing block being slidably connected to the frame part so that said firing block can slide rectilinearly, in a direction substantially perpendicular to a longitudinal axis of the barrel, between a closed position in which the firing block covers the rear end of the breech plug with the firing pin channel aligned with said breech plug, and an open position in which the firing block does not cover the rear end of the breech plug;
whereby the barrel is provided with a projection arranged for guiding the barrel in a guide groove in a barrel-protector of the firearm, when mounting the barrel to the barrel-protector; and
wherein the firearm further comprises an element made up of one single plastic piece that constitutes the barrel-protector and a butt of the firearm.