The invention relates to a trombone, a musical instrument in the brass family. The trombone distinguishes from other instruments in the brass family particularly by having a telescoping slide mechanism. The telescoping slide mechanism allows to vary the functional length of the tube, thereby allowing a player to change the pitch. In addition to the telescoping slide mechanism, a trombone may or may not also comprise one or more valves to additionally change the pitch of the instrument. The latter trombones are known as hybrid trombones or valve trombone.

The sound of instruments in the brass family is largely perceived as sharp and piercing. However, some members from the brass family have more warm and round sounding variants. In this context, the trumpet and the flugelhorn can be given as examples. The construction and dimensions of trumpet and flugelhorn are highly similar. Due to the form of the tube, the trumpet sounds significantly more sharp and piercing compared to the more warm and rounded sound of the flugelhorn. In the trumpet, the tube is largely shaped cylindrical meaning that the inner diameter of the tube remains largely constant over its length. In the flugelhorn, the tube has a longer conical portion meaning that the inner diameter of the tube increases over the greater part of its length.

US 1385202 describes a trombone and describes the objective to reduce the portion of cylindrical tubing in the instrument to a minimum. In other words, this document aims to continuously and gradually increase the inner diameter of the bore in the direction of travel of the sound vibrations. This document teaches that the most desirable tones from an instrument of his character can be produced when, to the greatest extent mechanically possible, the vibrations produced in the mouth-piece be conveyed to the bell of the instrument through a constantly and gradually enlarging pipe.

It is an object of the present invention to further improve the existing trombones to further improve the sound.

To this end, the invention provides a trombone comprising a tube extending between a mouthpiece and a bell, the tube having a telescoping slide mechanism with a first leg, a U-bend and a second leg, the telescopic slide mechanism comprising, for each of the first leg and the second leg, a static tube section connected to the mouthpiece and the bell, respectively, and a slidable tube section connected to the U-bend, characterized in that at least one of the first leg and second leg is provided with an intermediate tube section and wherein inner diameters of the tube sections are chosen to increase in a downstream direction to obtain a stepwise conical effect in the telescoping slide mechanism. The invention is based on the insight that by providing an intermediate tube section in the telescoping slide mechanism in at least one of the legs, a more gradual increase in diameter can be obtained without affecting the functional cooperation of the adjacent telescoping sections. Indeed the segments of the telescoping slide mechanism that overlap during normal use of the trombone cannot be made conical since this would affect the substantially air-tight connection between adjacent sections. Only when these segments are cylindrical, a proper functional connection can be realized. Therefore it is only possible to increase the inner diameter from one section to another section while each section itself is largely cylindrical. Increasing the diameter in steps from one section to an adjacent section is also referred to as stepwise conical. By providing at least one intermediate section, two advantages are obtained. Firstly, there is at least one extra step to enlarge the inner diameter in the stepwise conical telescoping slide mechanism, making the resulting overall inner shape more flowing and gradual. Secondly, the length of the individual segments decreases because the total length of the telescoping slide mechanism is divided over at least one extra section. This reduces the complexity of the interconnection of the adjacent sections while providing an improved conical effect. Both of these advantages improve the sound of the instrument, making it more warm and round, and improve the touch and feel of the instrument for the player. Preferably the telescoping slide mechanism is provided to vary the functional length of the tube to change a pitch.

Preferably tube section overlap zones are present between adjacent tube sections and wherein stockings are provided in the overlap zones to reduce friction in the telescopic slide mechanism. Preferably each stocking is formed as a tube thickening located at a downstream end of a tube section, which tube thickening corresponds to an inner diameter of the adjacent tube section. Tube sections are made cylindrical and with inner and outer diameters to allow the smaller tube section to slide inside the larger tube section. The thickening is preferably largely barrelshaped and is provided to reduce the friction to make the sliding less difficult and to improve the sealing.

Preferably the intermediate tube section is slidable with respect to the adjacent static tube section and is slidable with respect to the adjacent slidable tube section. Preferably the intermediate tube section is provided with a positioning mechanism to keep the intermediate tube section in a predetermined relative position with respect to the adjacent static tube section and the adjacent slidable tube section. When, in use, the intermediate tube section slides with respect to both the static tube section and the slidable tube section, the stepwise conical effect may be optimized. Several embodiments may be developed with one or more subsequently located intermediate tube sections, arranged between the static tube section and the slidable tube section. Depending on the number of intermediate sections, and the shape and design, the relative position of the intermediate sections in between the static and slidable tube sections are preferably kept substantially constant. Independent of the number of intermediate sections, the proportion of the relative travel distances of adjacent sections is preferably kept substantially constant.

Preferably the positioning mechanism is adapted to keep the intermediate tube section substantially centralized between the adjacent static tube section and the adjacent slidable tube section. In one preferred embodiment, a single intermediate section is provided in one or in each leg between the static section and the slidable section. By keeping this intermediate section substantially centralized between the static and slidable section improves the distribution of the stepwise conical elements.

Preferably the positioning mechanism is connected to at least one of the static tube sections and to at least one of the adjacent sliding tube sections. In one embodiment, the positioning mechanism comprises an elastic member that is at one end connected to the static tube section, at another end to the sliding tube section and that is substantially centrally connected to the intermediate tube section. This is a simple yet suboptimal way of keeping the intermediate part substantially centralized between the static and the slidable section. In another embodiment, a belt or chain drive is provided which is arranged to keep the intermediate tube section substantially centralized. Further alternatively, spindle shaped elements with a substantially large pitch may be used.

Preferably the positioning mechanism comprises a speed reduction mechanism adapted to reduce a first speed of the intermediate tube section with respect to the static tube section compared to a second speed of the sliding tube section with respect to the static tube section. The speed reduction mechanism may be embodied using a first belt or chain drive that follows the movement of the slidable section with respect to the static section and with a second belt or chain drive, operationally coupled to the first belt or chain drive, that moves synchronous but at a reduced speed. Preferably the ratio of the first speed to the second speed is about 1 to 2.

Preferably the positioning mechanism is connected to an outer side of the tubes of the telescopic slide mechanism. Preferably the positioning mechanism is connected to only one of the first leg and second leg. In this way the weight of the positioning mechanism may be kept minimal and the location of the positioning mechanism on the trombone may be optimized so that it does not affect a player in normal playing conditions.

Preferably at least one intermediate tube section comprises a first intermediate tube section provided in the first leg and comprises a second intermediate tube section provided in the second leg. In this way, each leg comprises at least three pieces sliding with respect to each other. This increases the possibilities to improve the stepwise conical effect of the tube.

Preferably the first intermediate tube section is rigidly connected, via a connection piece, to the second intermediate tube section such that a relative position of the first intermediate tube section with respect to the adjacent static tube section is substantially identical to the relative position of the second intermediate tube section with respect to the adjacent static tube section. The connection piece keeps the two intermediate tube sections, one in the first leg and the other one in the second leg, synchronously moving. This further optimizes the stepwise conical effect. It has a further advantage in that when a positioning mechanism is provided at one leg, keeping one of the intermediate tube sections in an optimal position, the other intermediate tube section is also kept in the optimal position via the connection piece. In an alternative embodiment however, different intermediate sections may be positioned in their respective leg via different positioning mechanisms to optimize the position in each leg separately.

Preferably a tuning slide is arranged downstream of the telescoping slide mechanism, which tuning slide is statically connected to the bell bow and the bell. Preferably an inner diameter of the bell bow and the bell substantially continuously increases in the downstream direction.

The invention will now be described in more details with respect to the drawings illustrating some preferred embodiments of the invention. In the drawings: figure 1 illustrates a trombone according to the prior art; figure 2 illustrates a telescoping slide mechanism usable in a trombone according to an embodiment of the invention; figure 3 illustrates an embodiment of a positioning mechanism mounted on the telescoping slide mechanism of figure 2; and figure 4 schematically illustrates a trombone according to a preferred embodiment of the invention.

In the drawings a same reference number has been allocated to a same or analogous element.

In the context of the invention, the trombone is defined as a brass instrument with a telescoping slide mechanism. The term ‘telescoping’, in the broadest meaning, relates to the sliding of one pipe element over another pipe element without adding or implying that the diameters of the pipe elements follow a certain order. The telescoping slide mechanism is realized by slidingly fitting adjacent pipe sections.

Figure 1 shows an embodiment of a trombone 1 according to the prior art. The trombone 1 comprises an assembly of pipes together forming an air channel extending between a mouthpiece 2 and a bell 16. The total length of the assembly of pipes can be varied via the telescopic slide mechanism, explained hereunder. In use, sound is produced by a player’s blowing air in the mouthpiece while vibrating the lips, causing air inside the assembly of pipes to flow and to vibrate. Using the telescoping slide mechanism, the player can vary the length of the assembly of pipes to change the pitch. Some trombones may be provided with valve attachments (not shown) to further change the pitch of the trombone. These basic principles of operation of the trombone 1 are the same for the prior art trombone and the trombone of the present invention.

Figure 1 shows the telescoping slide mechanism with the separate pieces not assembled together. In particular, figure 1 shows the mouthpiece 2 being connected to a first static tube section 3. A first slidable tube section 4 is adapted to be slid over the first static tube section 3. Preferably, the outer diameter of a distal end of the first static tube section 3 comprises a widening, also referred to as a stocking (not shown in figure 1). A stocking is defined as a local widening of the outer diameter on a largely cylindrical tube section. Stockings are used to reduce friction. The inner diameter of the slidable tube section 4 corresponds to the outer diameter of the first static tube section 3, and preferably to the outer diameter of the stocking, such that the first slidable tube section 4 can slide over the first static tube section 3. The first static tube section 3 and the first slidable tube section 4 together form the first leg of the telescoping slide mechanism of the trombone 1.

Figure 1 shows the bell 16 of the trombone 1 being connected to a second static tube section 7 via a static bell tube section 15, tuning slide 11, static shoulder tube section 14. A second slidable tube section 6 is adapted to be slid over the second static tube section 7. Preferably, a distal end of the second static tube section 7 comprises, analogue to the first static tube section 3, a thickening, also referred to as a stocking (not shown in figure 1). The inner diameter of the second slidable tube section 6 corresponds to the outer diameter of the second static tube section 7, and preferably to the outer diameter of the stocking, such that the second slidable tube section 6 can slide over the second static tube section 7. The second static tube section 7 and the second slidable tube section 6 together form the second leg of the telescoping slide mechanism of the trombone 1.

Each one of the first and second static tube sections 3 and 7 and the first and second slidable tube sections 4 and 6 are cylindrical. This means that the inner diameter of each of these segments is substantially constant. Typically, the first and second static tube sections 3 and 7 are formed substantially identical, meaning also with substantially identical diameters. Also typically, the first and second slidable tube sections 4 and 6 are formed substantially identical, meaning also with substantially identical diameters. The first and second slidable tube sections 4 and 6 are interconnected by a U-bend 5. The U-bend 5 may be provided with a water outlet valve. The term U-bend is not used to limit the bend to the exact form of the U, and allows additional shapes and curves to be formed in the U-bend. The term U-bend is merely used as a connection between two tube sections extending in opposite directions.

The first and second static tube sections 3 and 7 are interconnected by a static frame piece 8. At least one of the first and second slidable tube sections 4 and 6 is provided with a handle 9 close to the mouthpiece 2. In figure 1, the handle 9 also interconnects the first and second slidable tube sections 4 and 6 at the side of the mouthpiece 2, giving extra support to these tube sections 4 and 6.

The telescoping slide mechanism is connected to a shoulder piece tube section 14. During playing, the instrument may rest on one hand of the player in a proximity of the shoulder of the player. The telescoping slide mechanism is largely located in front of the player. The shoulder piece tube section 14 extends towards the back side of the player, where a counterweight 12 is arranged. The counterweight 12 brings balance in the instrument when the trombone 1 rests in a normal playing position on the hand of a player. Typically, a tuning slide 11 is provided. The tuning slide 11 is provided to slide with respect to the static shoulder tube section 14 and the static bell tube section 15, which sliding is illustrated with arrows 13. With the tuning slide 11, the base pitch of the trombone can be adjusted. The static bell tube section 15 extends between the tuning slide 11 and the bell 16.

In a typical trombone, the pipe is largely cylindrical up to the tuning slide 11. Only after the tuning slide 11, in the static bell tube section 15 and in the bell 16, the inner shape is conical. The invention is based on the insight that this cylindrical shape of the pipe gives a sharp and piercing sound.

Figures 2-4 illustrate differences between a prior art trombone 1 and a trombone 1 ’ of the invention. Elements and parts of the trombone 1’ of the invention are preferably all shaped and formed differently than corresponding elements and parts of the prior art trombone 1. Functionally however, many parts correspond between the trombone 1’ of the invention and the prior art trombone 1. To simplify the explanation of the invention, the elements and parts that functionally correspond are given the same reference number but with an apostrophe. Giving elements and parts the same name and number is not an admission that these elements and parts are fully known from the prior art.

Figure 2 illustrates a preferred embodiment of a telescoping slide mechanism of the invention. The telescoping slide mechanism comprises a number of subsequently arranged tube sections. In a downstream direction, the telescoping slide mechanism subsequently comprises a first static tube section 3’, a first intermediate tube section 17, a first slidable tube section 4’, a El- bend 5’, a second slidable tube section 6’, a second intermediate tube section 18 and a second static tube section 7’. The first static tube section 3’, first intermediate tube section 17 and first slidable tube section 4’ together form the first leg of the telescoping slide mechanism. The second static tube section 7’, second intermediate tube section 18 and second slidable tube section 6’ together form the second leg of the telescoping slide mechanism. Each tube section 3’, 17, 4’, 6’, 18 and 7’ is largely cylindrical meaning that the inner diameters of each of these tube sections is substantially constant. Although in this context it is noted that for the shown slide mechanism, it is not necessary that the first static tube section 3’ and the second slidable tube section 6’ have a substantially constant diameter since these sections have no other section sliding within them. Also the U-bend 5’ may be conical.

In the telescoping slide mechanism of figure 2, inner diameters of the tube sections 3’, 17, 4’, 6’, 18 and 7’ increase in the downstream direction. Although each one of the individual tube sections 3’, 17, 4’, 6’, 18 and 7’ is cylindrical, the combination of these tube sections 3’, 17, 4’, 6’, 18 and 7’ with their different diameters gives the telescoping slide mechanism a stepwise conical inner shape. Figure 2 shows the telescoping slide mechanism in an extended state wherein the length of the pipe is maximal. The skilled person understands that the telescoping slide mechanism may be retracted to reduce the length of the pipe of the telescoping slide mechanism. It will be clear that the lengths of the individual pipe sections 3’, 17, 4’, 6’, 18 and 7’ are unchangeable in normal use, however the overlap between the sections 3’, 17, 4’, 6’, 18 and 7’ increases and decreases so that the length of the pipe forming the telescoping slide mechanism, which is equal to the sum of the lengths of the individual pipe sections 3’, 17, 4’, 6’, 18 and 7’ minus the distances of the overlap between the sections 3’, 17, 4’, 6’, 18 and 7’, may be changed.

Each of the pipe sections 3’, 17, 6’ and 18 is preferably provided with a stocking. A stocking is defined as a thickening of the outer diameter of a pipe section. The thickening can be obtained by increasing the material thickness at the stocking. Preferably, the thickening is obtained by making both inner and outer diameter wider at the stocking. The stocking is preferably provided at each downstream end of the pipe sections 3’, 17, 6’ and 18. Each of these pipe sections have a subsequent downstream pipe section slideably arranged with respect to the pipe section. The inner diameter of the downstream pipe section preferably corresponds to the outer diameter of the stocking. Providing stocking not only reduces the friction during the sliding, but also facilitates the stepwise conical construction.

In the embodiment of figure 2, each of the first leg and second leg of the slidable telescoping mechanism is provided with a single intermediate tube section located between the static tube section and the slidable tube section. It will be clear however that it is also possible to provide only one of the legs of the slidable telescoping mechanism with an intermediate tube section, while the other leg of the slidable telescoping mechanism only comprises the static and slidable tube section. In another embodiment, one of both of the legs of the telescoping slide mechanism is provided with two or more subsequently arranged intermediate tube sections such that one leg comprises a total of four or more tube sections. In such embodiment, the intermediate tube section is slidable with respect to the adjacent static tube section, the adjacent slidable tube section or the adjacent intermediate tube section. In other words, multiple intermediate tube sections may slide with respect to each other.

Figure 2 shows how the first static tube section 3’ and the second static tube section 7’ are connected via the static frame piece 8’. The first slidable tube section 4’ and the second slidable tube section 6’ are connected via the U-bend 5’. Preferably, a connection piece 23 is provided to interconnect the first intermediate tube section 17 and the second intermediate tube section 18. The connection piece 23 is preferably connected to the upstream outer side of each of the first intermediate tube section 17 and the second intermediate tube section 18. During sliding, particularly in the retracted position, the majority of the first intermediate tube section 17 and the second intermediate tube section 18 is slid inside the first slidable tube section 4’ and second static tube section 7’, respectively, so that only the upstream outer side remains accessible. Therefore the connection piece 23 is preferably connected to this upstream outer side of the intermediate tube sections 17 and 18. The connection piece 23 keeps the relative positions of the intermediate tube sections 17 and 18 the same for the two legs of the telescoping slide mechanism. When the position of the intermediate tube sections 17 and 18 is controlled, only a single positioning mechanism should be provided because the connection piece 23 transfers the position of the one intermediate tube section to the other intermediate tube section. Alternatively, it is possible to provide a positioning mechanism for the intermediate tube section on each leg separately, thereby making the connection piece 23 superfluous.

Figure 2 schematically illustrates the purpose of the positioning mechanism 19. The positioning mechanism 19 connects to a static tube section, a slidable tube section and to an intermediate tube section to keep the intermediate tube section in a predetermined relative distance with respect to both the static and the slidable tube section. This is illustrated with the first distance 21, being the distance between a predetermined location on the static tube section and a predetermined location on the intermediate tube section, and with the second distance 20, being the distance between a predetermined location on the intermediate tube section and a predetermined location on the slidable tube section. In one embodiment, the first distance 21 is kept substantially equal to the second distance 20, meaning that the intermediate tube section is kept substantially centralized between the static tube section and the slidable tube section. Alternatively, a predetermined ratio is maintained. In such embodiment, the intermediate tube section would not be centralized, but would be offset towards or away from the static tube section.

The positioning mechanism 19 may be shaped and formed in different ways. Figure 3 shows one embodiment of the positioning mechanism 19. In figure 3, the positioning mechanism is mounted to the second leg of the telescoping slide mechanism. This is preferred for keeping an optimal mechanical balance in the trombone 1 ’ . The weight added by the positioning mechanism 19 can then easily be compensated in the counterweight.

Figure 3 shows how the second static tube section 7’ is provided with an extension arm towards the U-bend 5’. Wheels are mounted on the second static tube section 7’. In particular, a first wheel 24 is mounted at the downstream end of the second static tube section 7’. It will be clear that the terms downstream and upstream relate to a normal flowing direction of the air through the tubes while playing the trombone. A second wheel 25 is mounted more centrally on the second static tube section 7’. A third wheel 26 is mounted at an upstream end of the second static tube section 7’, preferably on the extension arm.

The first wheel 24 is a double wheel meaning it is adapted to connect two belts. A first belt runs over the first wheel 24 on a first section with a first, larger diameter. A second belt runs over the first wheel 24 on a second section with a second, smaller diameter. Due to the difference in diameter, the running speeds of the two belts are different. However, because the two belts are running over a single wheel, with a single rotational speed, the speed ratio is predetermined. The second wheel 25 is a single wheel meaning it only connects one belt. The third wheel 26 is also a single wheel meaning it only connects to one belt.

A first belt, also referred to as slidable belt 28 because it connects to the slidable tube sections 6’, 4’, runs over the first section of the first wheel 24 as well as over the third wheel 26. A second belt, also referred to as intermediate belt 27 because it connects to the intermediate tube sections 17, 18, runs over the second section of the first wheel 24 as well as over the second wheel 25. The ratio between the running speed of the intermediate belt 27 and the running speed of the slidable belt 28 is predetermined. The center-to-center distance between the wheels holding the slidable belt 28 is preferably at least equal to the maximum sliding distance of the slidable tube sections 4’, 6’ with respect to the static tube sections 3’, 7’ during normal use of the trombone. The center-to-center distance between the wheels holding the intermediate belt 27 is preferably at least equal to the maximum sliding distance of the intermediate tube sections 17, 18 with respect to the static tube sections 3’, 7’ during normal use of the trombone.

The slidable belt 28 is connected via a slidable tube connector 29 with at least one of the slidable tube sections 4’, 6’. The slidable tube connector 29 is rigidly connected to an upstream outer end of at least one of the slidable tube sections 4’, 6’. The upstream outer end of the slidable tube section 4’ of the first leg of the telescoping slide mechanism is located more proximal compared to the upstream outer end of the slidable tube section 6’ of the second leg of the telescoping slide mechanism, which is located at the U-bend 5’. Therefore in the shown embodiment, the slidable tube connector 29 is rigidly connected to an upstream outer end of the first slidable tube sections 4’. This allows the slidable tube connector 29 to be as small as possible. The slidable tube connector 29 preferably also forms or comprises the handle 9’, as is shown in figure 3. The handle 9’ is used by the player of the trombone 1’ to manually control and adjust the position of the slidable tube sections 6’ and 4’ with respect to the static tube sections 3’ and 7’.

The handle 9’ may be alternatively directly connected to an outer end of the slidable tube section 4’ or the slidable tube section 6’ . Further alternatively, the handle 9’ may be connected to one of the intermediate tube sections 17, 18. In the latter case, the moving distance of the handle 9’ is merely a fraction of the total moving distance of the slidable tube section. This would allow the trombone or a trombone-like instrument to be designed with a sliding distance of the slidable tube section which is significantly further than reachable by an average person’s arm.

The intermediate belt 27 is connected via an intermediate tube connector 30 with at least one of the intermediate tube sections 17, 18. The intermediate tube connector 30 is rigidly connected to an upstream outer end of at least one of the intermediate tube sections 17, 18. The upstream outer end of the intermediate tube section 17 of the first leg of the telescoping slide mechanism is located more proximal compared to the upstream outer end of the intermediate tube section 18 of the second leg of the telescoping slide mechanism. Therefore in the shown embodiment, the intermediate tube connector 30 is rigidly connected to an upstream outer end of the first intermediate tube section 17. This allows the intermediate tube connector 30 to be as small as possible. The connection piece 23 synchronizes the movement of the intermediate tube sections 17, 18 so that it is sufficient to only connect a single intermediate tube section to the intermediate belt 27.

Based on the explanation above, the skilled person understands that the different tube sections can slide with respect to each other and that the relative positions and speeds of the different tube sections can be controlled. The skilled person also understands that using the same working principles, a belt may be added to drive an additional intermediate tube section (not shown). The positioning mechanism and setup as described above has been tested and proves not only to make the sound more round and warm because of the stepwise conical shape of the telescoping slide mechanism, but also to facilitate the sliding and operation of the telescoping slide mechanism. The setup as described above and shown in figures 2 and 3 brings a balance in the telescoping slide mechanism, which balance facilitates the playing and increases the fun.

In the telescoping slide mechanism as explained above, tube sections 6’, 3’ and U- bend 5’ may be formed conical instead of cylindrical because the inner walls of these tube sections are not used by other tube sections to slide in. Only the outer ends are slidingly connected to the downstream section, which would also be possible if the tube sections 6’ and 3’ would be conical.

Figure 4 shows a trombone 1 ’ according to a further preferred embodiment of the invention. In figure 4, the slide mechanism is not shown in much detail, and reference is made to figures 2 and 3 and the corresponding explanation. Figure 4 shows a trombone 1’ wherein the static shoulder tube section 14’ as well as the static bell tube section 15’ is made conical, meaning increasing the inner diameter in a downstream direction. This further increases the sound quality of the trombone 1’, making it more round and warm. The tuning slide is implemented differently compared to the prior art trombone 1 for minimizing the number of or length of the cylindrical sections in of the tube. In the embodiment of figure 4, only a single tuning slide 13’ is provided in a downstream end of the static shoulder tube section 14’. A counterweight 12’ is connected to a lower end of the bend, bringing the counterweight 12’ in the trombone 1’ of the invention further backward compared to the prior art trombone 1. This makes compensating for the weight added to the telescoping slide mechanism more easy.

The skilled person will appreciate on the basis of the above description that the invention can be embodied in different ways and on the basis of different principles. The invention is not limited to the above described embodiments. The above described embodiments and the figures are purely illustrative and serve only to increase understanding of the invention. The invention will not therefore be limited to the embodiments described herein, but is defined in the claims.