Patent Publication Number: US-2022228687-A1

Title: Coupling intended for an air motor

Description:
The invention relates to a coupling for connecting a compressed air source to an air motor, comprising a housing with a housing channel leading to a compressed air connection, a piston axially adjustable in the housing channel and force-loaded by a spring element and has an axially extending piston channel which, when the coupling is connected to the air motor, merges into a connecting channel present in a pin element of the air motor, wherein the piston is adjustable in the direction of the compressed air connection by means of the pin element against the force applied by the spring element, wherein, in the absence of interaction between the pin element and the piston, the piston is in a first position due to the force applied by the spring element, in which the housing channel is shut off relative to the piston channel by means of a first seal extending between the piston and the housing channel, and, when the coupling is connected to the air motor, in a second position of the piston there is a compressed air connection between the housing channel, the piston channel and the connecting channel. 
     Air motors are used, for example, to drive tools. If these are made of stainless steel, they are particularly suitable for use in the food and chemical industries, as they meet hygienic requirements and operate reliably. For cleaning, such as disinfecting, the housing of corresponding air motors, the connection to the compressed air source must be removed. This is often time consuming. The same applies to the case when one compressed air supply is to be used for several air motors. 
     DE 1 756 105 U1 describes a complex self-closing valve for compressed air lines which has a spherical valve body with a conical extension, wherein a seal runs between the extension and the body. The valve body is connected to a sleeve. A spring element acts on the sleeve and is supported between a housing part and a shoulder extending from the sleeve. The sleeve is guided by sections of housing parts that can be assembled. 
     DE 68 09 307 U1 provides for a compressed air coupling attached to a wall or a ceiling, which is connected via a hose to a compressed air tool using a bayonet catch, by means of which a compressed air channel is released. 
     It is therefore the object of the present invention to provide a coupling for an air motor which allows both rapid disconnection and connection to a source of compressed air without any disadvantages in supplying the compressed air. The coupling should be alignable to an air motor to the desired extent, i.e. the coupling should be variably positionable. 
     According to another aspect, it should be possible to selectively lead the exhaust air away. 
     It should also open up the possibility of achieving a reduction in the sound level, which is quite high in air motors. 
     For solving the object, the invention essentially provides that the spring element runs between the compressed air connection and the compressed air connection side area of the piston, that radially running openings, via which the compressed air flows in the second position of the piston, start from the compressed air connection side area of the piston channel, that at least one exhaust air channel connected to the compressed air motor runs in the wall of the housing and passes through the wall in its compressed air connection side area, in particular the end face of the housing. 
     In particular, the invention also relates to a coupling for connecting a compressed air source to a compressed air motor, comprising a housing with a housing channel leading to a compressed air connection, a piston axially adjustable in the housing channel and force-loaded by a spring element, having an axially extending piston channel which, when the coupling is connected to the compressed air motor, merges into a connecting channel present in a pin element of the compressed air motor, wherein the piston is adjustable in the direction of the compressed air connection against the application of force by the spring element, wherein, in the absence of interaction between the pin element and the piston, the piston is in a first position due to the application of force by the spring element, in which the housing channel is shut off with respect to the piston channel by means of a first seal extending between the piston and the housing channel, and, with the coupling connected to the air motor, in a second position of the piston there is a compressed air connection between the housing channel, wherein the coupling is characterized in that the piston has a first section running on the compressed air motor side and a second section running on the compressed air connection side, in that the first section has a cylinder geometry on the outside and the piston channel runs inside it, in that the second section has a larger cross section compared to the first section and runs at a distance from the inner surface of the housing channel, in that the spring element is supported on the one hand on the compressed air connection side, preferably on the compressed air connection, and on the other hand on the first section, in that a first seal runs in the second section or in the transition region between the first and second sections, in that the housing channel has a contact surface, in that the first seal engages with the contact surface in the absence of interaction between the pin element and the piston and in that the piston channel has, in its compressed air connection side area, radially running openings which run with respect to the contact surface in such a way that, when the seal is not engaged with the contact surface, there is a connection between the housing channel and the piston channel, and when the seal is engaged with the contact surface, the connection is blocked. 
     According to the invention, a coupling is proposed which can be connected to an air motor, wherein the housing of the coupling has a compressed air connection and within the housing a piston is adjustable, which in a first position, in which the housing, i.e. the coupling, is disconnected from the motor connection, shuts off compressed air present in the housing, and in a second position, in which there is a connection to the air motor, the compressed air can flow to the air motor. 
     In particular, it is provided that the housing has at least one, preferably two, connections running in the direction of the longitudinal axis, such as channels or bores in the housing wall, via which exhaust air coming from the air motor is led away. Preferably, the removal is carried out via a hose, e.g. having a length of more than two, preferably more than three meters, connected to a muffler in order to achieve noise reduction. This has the advantage that the exhaust air from the air motor does not flow out directly in the region of the air motor, which would cause undesirable noise. 
     In order to optionally shut off the compressed air or connect it to the air motor, the first seal, which in particular extends from the piston, either engages or is spaced from a contact surface formed in the inner surface of the housing. In this region, the piston runs at a distance from the inner surface of the housing, virtually forming an annular space to allow compressed air to flow to the required extent. 
     The fact that the spring element acts on the end region of the piston on the compressed air connection side results in a simple design, in particular simple insertion and replacement of the spring element. The housing does not have to be taken apart. Rather, it is only necessary to disconnect the air pressure connection from the housing. 
     In particular, it is provided that the contact surface has a cone shape, i.e. the geometry of a cone. 
     Furthermore, it should be particularly emphasized that the piston consists of a first section extending on the air motor side with a cylinder geometry and a second section extending on the compressed air connection side, which is widened compared to the first section, i.e. has an effective cross-section that is larger than that of the first section. 
     The first seal can start from the second section. In particular, however, it is provided that the first seal extends in the transition region between the first and second sections, in particular in a groove via which the first section merges into the second section. 
     It should also be emphasized that the second section in longitudinal section preferably has a T-geometry with a transverse leg on whose surface on the compressed air connection side the spring element is supported with one of its ends. The other end of the spring element, which is in particular a helical spring, should be supported on the inner surface of the compressed air connection connected to the housing. 
     To securely fix the spring element, this surrounds the longitudinal leg of the second section of the piston, which preferably has a T-geometry in longitudinal section as mentioned above. 
     In order to exclude the possibility of compressed air escaping between the pin element and the coupling or the inside thereof, the invention provides in particular that a second seal runs parallel to the first seal in the inner surface of the housing, by means of which the pin element can be sealed off from the housing, wherein the distance between the contact surface for the first seal, specifically in the region on which the first seal rests when the coupling is locked, and the second seal is fixed in such a way that, when the first seal engages with the contact surface, the contact surface between the piston and the pin element runs between the contact surface, i.e. the contact region of the first seal on the contact surface, and the second seal. This ensures that false air cannot escape when the coupling is open, i.e. when the piston is moved in the direction of the compressed air connection against the force caused by the spring element by means of the pin element in order to space the first seal from the contact surface. The sealing of the second seal always acts until the first seal shows the desired sealing effect. In this position of the piston, compressed air can no longer flow through the radial openings and the piston channel. 
     Furthermore, a third seal is provided to provide a seal between the outer surface of the housing and the section of the air motor that receives the coupling. 
     As mentioned, the invention is also characterized in particular by the fact that at least one exhaust air connection to an exhaust air opening of the air motor runs in the housing, i.e. its wall. This at least one exhaust connection opens into a first hose connected to the housing of the coupling. Inside the first hose runs a second hose leading to the compressed air connection. 
     It is also an object of the invention to provide an air motor with a coupling, having one or more of the features previously explained. 
    
    
     
       Further details, advantages and features of the invention result not only from the claims, from the features to be taken from these—individually and/or in combination—but also from the following description of preferred embodiment examples. 
       Showing: 
         FIG. 1  a first embodiment of a quick coupling screwed onto an air motor, 
         FIG. 2  the quick coupling according to  FIG. 1 , 
         FIG. 3  a second embodiment of a variably positionable coupling connected to an air motor, and 
         FIG. 4  the coupling according to  FIG. 3  with spaced air motor. 
     
    
    
     With the aid of the figures, the teaching according to the invention will be described, which relates to couplings for connecting an air source to an air motor or an air motor with a coupling. 
     In a first embodiment according to  FIGS. 1 and 2 , a coupling  10 , which may be referred to as a quick coupling, is connected to a section  12  of an air motor via a coupling nut  14 , as can be self-explanatorily seen in  FIG. 1 . The coupling  10  includes a housing  16  having a journal-shaped connection  18  connectable thereto for a connecting element generally referred to as a hose, which leads to a source of compressed air to supply compressed air to the air motor. The connection  18  extends centrally from the front region  20  of the housing  16 , which may also be referred to as the distal region with respect to the air motor. 
     The connection  18  opens into an inner space  22  of the housing  16 , to be designated as a housing channel, in which a piston  24  is adjustable in the longitudinal axis direction of the housing  16 , which is force-loaded in the direction of the proximal region of the housing  16 , i.e. the region of the connection with the air motor, by means of a spring, such as a helical spring  26 . 
     The piston  24  extends with a section on the pressure connection side at a distance from the inner wall  28  of the inner space  22 , so that there is an annular space  30  in which the compressed air is present or through which the compressed air can flow. The adjoining section of the piston  24 , which runs on the air motor connection side, is guided axially in the housing  16 , as is likewise self-explanatory from the Figs. 
     The piston  24  has a central recess, such as a bore  32 , in its region  30  near the air motor, which can also be described as a piston channel, from which radially extending openings  34 ,  36  extend, which pass peripherally through the piston  24 , as is likewise self-explanatory from the diagrammatic representation. 
     The piston  24  is sealed from the inner wall  28  by at least one circumferential seal  38 , which either blocks ( FIG. 2 ) or releases ( FIG. 1 ) a connection between the openings  34 ,  36  and the annular space  30 , depending on the position of the piston  24 . The latter is the case when the coupling  10  is connected to the air motor  12  by means of the coupling nut  14  and the piston  24  is displaced in the direction of the distal region, i.e. the end region  20 , of the housing  16  against the spring force and compressed air acting on it. This is made possible by the fact that a pressure element, such as a pin element or pin  40 , originates from the air motor  12  and extends in or through the connection  15  of the air motor  12 , onto which the coupling nut  14  is screwed, in such a way that, when the coupling  10  is connected to the air motor  12 , the pressure element or pin  40  interacts with the motor side end region  33  of the piston  24  in such a way that the latter is displaced in the direction of the distal region of the housing  16 , i.e. the spring  26  is compressed accordingly, as can be seen from  FIG. 1 . In this second position, the openings  34 ,  36  are connected to the annular space  30  so that compressed air can flow through the openings  34 ,  36  and  41 , the bore  32  in the piston  24  and an in this merging axially extending recess like a bore in the pressure element  40  and is connected to the air motor for actuating it. The bore  41  can also be referred to as a connecting channel. 
     Instead of the pin  40 , another design solution may be provided to adjust the piston  24  when the quick coupling  10  is connected to the air motor. In this respect, pressure element or pin  40  is to be understood as a synonym for corresponding possible solutions. 
     If the coupling  10  is disassembled, i.e. moved to the right in the diagrammatic representation of  FIG. 1 , the force acting on the piston  24  causes it to be displaced in the housing  16  in such a way that the openings  34 ,  36  are located between the proximal region of the housing  16  and the seal  38 , in the so-called first position, so that the connection to the annular space  30  is interrupted and thus compressed air can no longer flow through the bore  32  in the direction of the air motor  12 . 
     It is further apparent from the diagrammatic representations that within the housing  16 , and specifically in the embodiment example, two channels or bores  42 ,  44  are provided extending in the longitudinal direction of the housing  16 , which are connected to or merge with exhaust bores  46 ,  48  of the air motor  12  when the coupling  10  is connected thereto. The channels  42 ,  44  pass through the end face region of the housing  16  so that when the peripheral wall  50  of the housing  16  is surrounded by a hose, the exhaust air can then be discharged. In this case, the corresponding hose initially coaxially surrounds the hose connected to the compressed air source and extending from the journal section  18 . The hose carrying the exhaust air can be connected to a muffler to reduce the noise level. 
     The coupling  10  is preferably made of stainless material such as steel, so that hygiene requirements can also be met in this respect. 
     Another seal is located between the coupling nut  14  and the housing  16  of the coupling  10 . Also, a seal extends between the pressure element  40  and the inner wall  28  of the housing  16 . 
       FIGS. 3 and 4  show a particularly noteworthy embodiment of a coupling  110  which can be used in particular for an air motor in the food industry, without this being intended to restrict the teachings of the invention. Independently of this, the coupling  110 —like the coupling  10 —is not location-bound, so that a connection to air motors can be made without any problems, which are operated by hand, for example. In this case—as in the embodiment example of  FIGS. 1 and 2 —the coupling is directly connected to an air motor or a section  112  of the air motor. 
     To connect the section  112 , a coupling nut  114  is provided to receive the section  112  and extend from the coupling  100 , as illustrated in the diagrammatic representations. 
     A compressed air connection  118  can be connected to the housing  116  of the coupling  110 , which in particular passes through the end face  120  of the housing  116  and can be screwed into it. In this region, the housing  116  is formed such that an inner space, to be referred to as the housing channel  122 , is formed through which compressed air can flow through the coupling  110  to the air motor in a proximate manner via the connection  118 . 
     Within the housing channel  122  and adjustable in the axial direction is a piston  124 , which is force-loaded towards the proximal region of the coupling  110  by means of a spring element  126 , preferably in the form of a helical spring, i.e. in the direction of the region in which the air motor or the section  112  is connected to the coupling  110 . The opposite end region  120  may be referred to as the distal region of the coupling  110 . 
     The piston  124  comprises a first section  126  of cylindrical geometry and a second section  128  having a T-geometry in longitudinal section. In the first section  126  runs a central bore, to be referred to as piston channel  130 , which in its bottom region merges into radially extending openings  134 ,  136 , which pass through the piston wall to allow, depending on the position of the piston  124 , either compressed air to flow through the connection  118 , the housing channel  122  and the piston channel  130  to a connecting channel  138  extending in the section  112  for actuating the air motor, which channel extends within a hollow pin—also called pin element  140 —or to shut off the compressed air ( FIG. 4 ) when the coupling  110  is disconnected from the air motor. To this end, a first seal  142  is provided extending in the transition region between the first section  126  and the second section  128  of the piston  124 , namely in a groove  144 . 
     Here, the first seal  122  engages with the proximal outer surface  146  of the transverse leg  148  of the second section  128  of the piston  124 . The opposite distal outer surface  150  of the transverse leg  146  is supported by one end of the spring  126 . The opposite end is supported on the inside of the compressed air connection  118 , which can be screwed into the housing  116 . 
     The first seal  142  is associated with a contact surface  152  in the inner wall of the housing  116  of the coupling  110 , against which the first seal  142  engages when the flow of compressed air is to be shut off, i.e., when the air motor is disconnected from the coupling  110 . In this case, the spring  126  acts on the piston  124  in such a way that the piston  124  is displaced in the direction of the air motor connection side area to such an extent that the first seal  142  is in sealing contact with the contact surface  152 . Since the radially extending openings  134 ,  136  of the piston  124  are located between the proximal region of the housing  116 , i.e. the end face extending on the air motor side, and the contact surface  142  when the first seal  142  is in contact with the contact surface  152 , compressed air cannot flow via the openings  134 ,  136 . 
     If, in accordance with  FIG. 3 , the coupling  110  is connected to the section  112  of the compressed air motor, the journal  140  acts with its end face on the facing end face of the first section  126  of the piston  124  with the result that, when the piston  124  is moved axially—by turning the coupling nut  114 —in the direction of the compressed air connection  118 , the force caused by the spring  126  is overcome and thus the first seal  142  is spaced from the contact surface  152 . At the same time, the radially extending openings  134 ,  136  enter the region of the housing channel  122  in which the contact surface  142 , which has a cone geometry, extends with the result that compressed air can flow through the housing channel  130  and the openings  134 ,  136  into the connecting channel  138  and thus to the air motor. The connecting channel  138  extends in the pin  140 , which can also be referred to as a sleeve. The impact surface between the pin  140  and the first portion  126  of the piston  124  is indicated by reference number  154  in  FIG. 3 . 
     A second seal  156  is recessed in the inner wall of the housing  116 , via which the housing  116  is sealed from the journal  140 , until the first seal  142  sealingly engages the contact surface  152 . Accordingly, the distance between the second seal  156  and the contact surface  152  is matched with respect to the length of the piston  124  and thus the impact surface  154  with respect to the distance between the first seal  142  and the impact surface  154 . 
     A third seal  57  seals the section  122  from the housing  116 , preferably recessed in the housing wall. 
     As in the embodiment example in  FIGS. 1 and 2 , exhaust air channels  160 ,  162  extend inside the housing wall, through which air recirculated from the air motor can flow. The exhaust air is directed away from a hose element  164  that surrounds the housing  116 . A hose  166  connected to the compressed air connection  118  extends within the corresponding hose  164 . 
     Thus, couplings  10 ,  110  are available to provide a compressed air supply and an exhaust air supply. The noise level when using the air motor is reduced at the same time, especially when the exhaust air is led away via a hose, e.g. 3 meters long, and then passes through a muffler. 
     To reduce noise, it is provided in particular that the first hose element  164 , i.e. the hose via which the exhaust air is led away, opens into a housing which is made in particular of plastic. The supply air hose  166  carrying the compressed air is passed through the center of the housing in particular and sealed with an O-ring. The exhaust air coming out of the exhaust hose can escape through mufflers mounted in or on the housing. 
     The invention relates to a coupling  10 ,  110  for connecting a compressed air source to an air motor, comprising a housing  16 ,  116  with a housing channel leading to a compressed air connection  18 ,  118 , a piston  24 ,  124  axially adjustable in the housing channel  22 ,  122  and force-loaded by a spring element  26 ,  126 , having an axially extending piston channel  30 ,  132  which, when the coupling is connected to the air motor, merges into a connecting channel  41 ,  138  present in a pin element  40 ,  140  of the air motor, wherein the piston is adjustable in the direction of the compressed air connection by means of the pin element against the application of force by the spring element, wherein in the absence of interaction between the pin element and the piston, the piston is in a first position due to the application of force by the spring element, in which the housing channel is shut off with respect to the piston channel by means of a first seal  38 ,  142  extending between the piston and the housing channel, and, with the coupling connected to the air motor, in a second position of the piston there is a compressed air connection between the housing channel, the piston channel and the connecting channel, wherein the coupling is characterized in that the spring element  26 ,  126  extends between the compressed air connection  18 ,  118  and the compressed air connection side area of the piston  24 ,  124 , in that radially extending openings  34 ,  36 ,  134 ,  136 , via which the compressed air flows in the second position of the piston, extend from the compressed air connection side area of the piston channel  30 ,  132 , and in that at least one exhaust air channel  42 ,  44 ,  160 ,  162 , which is connected to the compressed air motor, extends in the wall of the housing  16 ,  116  and passes through the wall in its compressed air connection side area, in particular the end face of the housing. 
     In particular, the invention relates to a coupling  10 ,  110  for connecting a compressed air source to an air motor, comprising a housing  16 ,  116  with a housing channel leading to a compressed air connection  18 ,  118 , a piston  24 ,  124 , axially adjustable in the housing channel  22 ,  122  and force-loaded by a spring element  26 ,  126  having an axially extending piston channel  30 ,  132  which, when the coupling is connected to the air motor, merges into a connecting channel  41 ,  138  present in a pin element  40 ,  140  of the air motor, wherein the piston is adjustable in the direction of the compressed air connection by means of the pin element against the application of force by the spring element, wherein, in the absence of interaction between the pin element and the piston, the piston is in a first position as a result of the application of force by the spring element, in which first position the housing channel is shut off with respect to the piston channel by means of a first seal  38 ,  142  extending between the piston and the housing channel, and, with the coupling connected to the compressed air motor, in a second position of the piston there is a compressed air connection between the housing channel, the piston channel and the connecting channel, wherein the coupling is characterized in that the piston  24 ,  124  has a first section  126  running on the compressed air motor side and a second section  128  running on the compressed air connection side, in that the first section has a cylinder geometry on the outside and the piston channel  132  runs inside it, in that the second section has a larger cross section compared to the first section and runs at a distance from the inner surface of the housing channel  122 , in that the spring element  126  is supported on the one hand on the compressed air connection side, in particular on the compressed air connection  118 , and on the other hand on the first section in that a first seal  142  runs in the second section or in the transition region between the first and second sections, in that the housing channel has an contact surface  152 , in that the first seal engages the contact surface in the absence of interaction between the pin element  140  and the piston and in that the piston channel has, in its compressed air connection side area, radially extending openings  134 ,  136  which extend with respect to the contact surface in such a way that, when the seal is not engaged with the contact surface, there is a connection between the housing channel and the piston channel, and when the seal is engaged with the contact surface, the connection is blocked. 
     In particular, the invention provides that the contact surface  152  has a cone shape. 
     It is further provided that the first section  126  transitions into the second section  128  via a groove  144  in which the first seal  142  extends. 
     Also, the invention is characterized in that the second section  128  has a T-shape in longitudinal section with a transverse leg  148 , wherein the spring element, such as a helical spring, is preferably supported on the one hand on compressed air connection side face  146  of the transverse leg and on the other hand on inner surface of the compressed air connection  118  connected to the housing  116 . 
     Preferably, it is provided that the housing channel  122  has in its inner side a circumferential second seal  156  running parallel to the first seal  142 , via which the pin element  140  can be sealed with respect to the housing channel  122 , wherein the distance between the contact region of the first seal on the contact surface  152  and the second seal is defined in such a way that, when the first seal bears against the contact surface, the impact surface  154  runs between the piston  124  and the pin element between the contact surface and the second seal. 
     The invention is also characterized in that at least one exhaust air connection  160 ,  162 , such as a channel or bore, extending from the air motor extends in the wall of the housing  116  and passes through the compressed air connection side area of the wall, in particular its end face  120 . 
     The invention is further characterized in that the housing  16 ,  116  is connected to a first hose element  164  into which the at least one exhaust connection opens. 
     In particular, the invention is characterized in that from the end region of the housing  16 ,  116  remote from the compressed air motor connection originates the compressed air connection  18 ,  118 , which is designed in such a way that a second hose element  166  can be connected thereto, which is surrounded in regions by the first hose element  164 . 
     Also characteristic of the invention is that the first hose element  164  is formed or connected to a device to be connected to a muffler. 
     More preferably, the first hose element  164  has a length of at least 200 cm, preferably of at least 300 cm. 
     In particular, the first hose element  164  opens into a housing preferably made of plastic. In this, the exhaust air exits the first hose element  164  and then passes through mufflers mounted on or in the housing. This results in a considerable reduction in noise. 
     Furthermore, the hose  166  supplying the compressed air is passed through the housing and sealed with respect thereto via, for example, an O-ring. Thus, coaxial routing of the compressed air hose  166  and the exhaust air hose  164  is possible in a simple manner. 
     In particular, the invention provides that the coupling  10 ,  110  is not stationary, but rather connectable to an air motor at a desired location. 
     Also, the invention features an air motor with a coupling characterized by at least some of the features previously described.