Patent Publication Number: US-8991815-B2

Title: Separating and taking out device and separating and taking out method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2013-114160, filed on May 30, 2013, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a separating and taking out device and a separating and taking out method. 
     BACKGROUND 
     A separating and taking out device is used in equipment such as printers, copying machines, automatic teller machines (ATMs) and mail article processors. The separating and taking out device separates stacked media such as paper sheets one by one from a piled stack composed of the stacked media. The separating and taking out device is required to have performance to separate media one by one reliably. In some cases, such a separating and taking out device can not separate media certainly, due to meshed concave and convex shapes on surfaces of media or an electrostatic attraction force, for example. Accordingly, a technique of reducing friction force between stacked media by oscillating an ultrasonic vibrator in the vicinity of surfaces of stacked media is proposed. 
     However, in some cases, it is difficult depending on a type of media to reducing friction force between stacked media sufficiently and to separate media one by one reliably. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a configuration diagram schematically illustrating a separating and taking out device according to a first embodiment. 
         FIG. 2  is a cross-sectional view taken along A-A of the separating and taking out device of  FIG. 1 . 
         FIG. 3  is a conceptual diagram illustrating a flow of air according to the first embodiment. 
         FIGS. 4A and 4B  are views for explaining a measurement result of a levitation height of a medium. 
         FIGS. 5A to 5C  are views illustrating measurement results of a friction force of the separating and taking out device according to the first embodiment. 
         FIG. 6  is a configuration diagram schematically illustrating a main portion of a separating and taking out device according to a second embodiment. 
         FIGS. 7A to 7C  are views for explaining measurement results of a friction force of the separating and taking out device according to the second embodiment. 
         FIG. 8  is a configuration diagram schematically illustrating a main portion of the separating and taking out device according to a third embodiment. 
         FIG. 9  is a configuration diagram schematically illustrating a main portion of a separating and taking out device according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According to one embodiment, a separating and taking out device is provided. The separating and taking out device has a feeding base, a takeout part, a support part and an ultrasonic vibrator. The feeding base places a piled stack. The piled stack is composed of a plurality of media stacked in a direction. The taking out part takes out the plurality of media one by one from one end in the direction of the piled stack. The support part has a facing surface opposing a side surface of the piled stack. The ultrasonic vibrator has a vibrating surface opposing the end in the direction of the piled stack and one end in the direction of the support part. The ultrasonic vibrator oscillates the vibrating surface along a line connecting the vibrating surface with a gap between the side surface of the piled stack and the facing surface of the support part. 
     Hereinafter, further embodiments will be described with reference to the drawings. In the drawings, the same reference numerals denote the same or similar portions respectively. 
     A first embodiment will be described with reference to  FIG. 1  and  FIG. 2 . 
       FIG. 1  is an configuration diagram schematically illustrating a separating and taking out device according to a first embodiment.  FIG. 2  is a cross-sectional view taken along A-A of the separating and taking out device of  FIG. 1 . 
     A separating and taking out device  100  is used in printers, copying machines, automatic teller machines (ATMs), mail particle processors etc. The separating and taking out device  100  separates and takes out sheet media such as printing paper, bills, copy paper, postcards, envelopes or securities one by one. 
     The separating and taking out device  100  is suitable to separate and take out media of low permeability in particular. The media of low permeability are coating paper, media made of plastic or metal etc. Permeability of media is expressed by a numerical value as air permeability of the JIS Standards (JIS P 8117), for example. 
     Specifically, the air permeability is represented by a time necessary to transmit air of 100 ml through a medium having an area of 645 mm 2  under a pressure of 20.6 kPa. Air permeability of normal postal cards is about 60 seconds. The separating and taking out device  100  is also applicable to media of low permeability having air permeability larger than 60 seconds. The function of the separating and taking out device  100  to separate and take out media having permeability is enhanced compared to a conventional technique. 
     The separating and taking out device  100  of  FIG. 1  has a sheet feeding base  20 , a separating and taking out portion  30 , a support part  40  and an ultrasonic vibrator  50 . Media  10  are stacked in one direction (z axis direction) on the sheet feeding base  20 , and forms a piled stack  10   a  placed on the sheet feeding base  20 . The separating and taking out portion  30  separates and takes out the media  10  in a takeout direction (x axis direction) from one end (an upper end) of the piled stack  10   a  of the media  10  in the z axis direction. The support part  40  contacts with at least a portion of side surfaces of the media  10  parallel to the z axis direction (side surfaces parallel or vertical to the x axis direction). The ultrasonic vibrator  50  has a vibration surface  51  which opposes to a portion of a surface of one of the stacked media  10  on an uppermost surface side and to a portion of the support part  40 . 
     Further, the separating and taking out device  100  has a measuring unit  60 , a moving unit  70  and a control unit  80 . The measuring unit  60  measures one position of the one of the stacked media  10  on an uppermost surface side. A well-known medium conveying mechanism can be used for the moving unit  70 . The moving unit  70  has a moving base  71 , an elastic structure  72 , a rack  73  and a pinion  74 . The moving base  71  supports the sheet feeding base  20  in the z axis direction through the elastic structure  72 . The control unit  80  controls operations of the separating and taking out portion  30 , the ultrasonic vibrator  50 , the measuring unit  60  and the moving unit  70 . 
     The piled stack  10   a  of the media  10  is set on the sheet feeding base  20  as described above. The separating and taking out device  100  separates and takes out the media  10  from an upper end portion of the piled stack  10   a  set on the sheet feeding base  20 , one by one. One surface of the one of the stacked media  10 , which is positioned at an uppermost end portion of the piled stack  10   a  and is processed first, is a top surface of the piled stack  10   a . The opposite surface of the one of the piled stack  10   a  which opposes to the top surface is a bottom surface. Four surfaces other than the top surface and the bottom surface are side surfaces. 
     The sheet feeding base  20  has a guide plate  21  which forms a conveying path of the media  10  between the sheet feeding base  20  and a convey roller  32  in the takeout direction (x axis direction). 
     The separating and taking out portion  30  has a takeout roller  31  and the convey roller  32 . The takeout roller  31  is arranged to contact with the top surface of the piled stack  10   a  of the media  10 . When the takeout roller  31  rotates in a direction of an arrow T 1 , one of the media  10  on the uppermost surface side which contacts with the takeout roller  31  is conveyed in the takeout direction (x direction), and is taken out from the piled stack  10   a.    
     Further, the convey roller  32  is arranged in a downstream from the takeout roller  31  in the takeout direction (x axis direction). When the convey roller  32  rotates in a direction of an arrow T 2 , each media  10  which is taken out by the takeout roller  31  is further conveyed in the x direction in the convey path between the convey roller  32  and the guide plate  21  of the sheet feeding base  20 . 
     As illustrated in  FIG. 2 , the support part  40  has a facing surface or contact surface  41  which opposes to or contacts a side surface of the piled stack  10   a  of the media  10 , and a top surface  42  which is nearly parallel to the top surface of the piled stack  10   a . In the present embodiment, the support part  40  contacts with a portion of the side surface of the piled stack of the media  10  which is vertical to the y axis direction orthogonal to the z axis direction and the x axis direction. 
     The support part  40  contacts with the portion of the side surface of the piled stack  10   a  so that it is possible to align the side surfaces of the media  10  of the piled stack  10   a . A material of high rigidity such as metal can be used for the support part  40 , for example. 
     As illustrated in  FIG. 2 , the ultrasonic vibrator  50  is a vibrator which oscillates the vibration surface  51  to supply compressed air along a line  110  which connects the vibration surface  51  with a gap  54  between the side surface of the piled stack  10   a  of the media  10  and the contact surface  41  of the support part  40 . For the vibrator, those which oscillate at a specific frequency of an object such as a bolting Langevin type transducer or a bimorph Type transducer can be used. An ultrasonic wave is within a range of an acoustic wave which is inaudible to people depending on individual differences of people who handle devices, for example, within an acoustic range of 20 kHz or more. The vibration surface  51  may not have a circular shape and desirably has a rotationally symmetrical shape. The line  110  desirably passes through the center or the gravity center of the vibration surface  51  of the ultrasonic vibrator  50 , is vertical to the vibration surface  51  and is vertical to the top surface of the piled stack  10   a , i.e., parallel to the z axis. 
     The vibration surface  51  of the ultrasonic vibrator  50  opposes to the top surface of the piled stack  10   a  of the media  10  and the top surface  42  of the support part  40 . When the opposing area of the vibration surface  51  and the top surface of the piled stack  10   a  is S 1  and an opposing area of the vibration surface  51  and the top surface  42  of the support part  40  is S 2 , the area rate S 1 :S 2  is desirably 1:1. The opposing areas are obtained by projection in the z axis direction. According to the setting, when the line  110  passes through the center of the vibration surface  51  and is vertical to the vibration surface  51 , the center of the vibration surface  51  at which a pressure of compressed air of an ultrasonic wave is the highest directly below the vibration surface  51  opposes to the gap  54  between the side surface of the piled stack  10   a  of the media  10  and the contact surface  41  of the support part  40 . As a result, it is possible to efficiently supply air to the gap  54 . 
       FIG. 3  is a conceptual diagram illustrating an air flow according to the present embodiment. When the vibration surface  51  of the ultrasonic vibrator  50  oscillates at a vibration point, compressed air  55  is produced between the vibration surface  51  and both of the top surface of the piled stack of the media  10  and the top surface  42  of the support part  40 , by an acoustic radiation pressure. The compressed air flows in the gap  54  between the side surface of the piled stack of the media  10  and the contact surface  41  of the support part  40  due to a pressure difference, and flows in between the stacked media  10  from the gap  54 . In this case, simultaneously, when the vibration surface  51  of the ultrasonic vibrator  50  oscillates at a vibration point, a traveling wave is produced. The traveling wave spreads from the vibration point above the top surface of the piled stack of the media  10  along the xy plane in  FIG. 2 . The traveling wave causes the air which flows in between one of the media  10  on an uppermost end side and another one of the media  10  on a second uppermost surface side to spread along the xy plane from a vibration point. Thus, it is possible to float the media  10  and to reduce a friction force between the media  10  by a hydrostatic bearing effect. In particular, it is possible to reduce the friction force between the one of the media  10  on the uppermost end side and the other one of the media  10  on the second uppermost surface side much. As a result, it is possible to separate and take out the media  10  one by one from the piled stack, more reliably. 
     The embodiment and a comparative example will be compared. According to the comparative example, when a vibration surface is oscillated by opposing the vibration surface of an ultrasonic vibrator entirely to a top surface of a piled stack of media, compressed air is produced between the vibration surface and the piled stack of the media by an acoustic radiation pressure. A friction force between stacked media is reduced to some degree by a hydrostatic bearing effect caused when this compressed air transmits through the media. 
     However, when air permeability of the media is low, the amount of compressed air which transmits through one of the media to be separated is small or the compressed air does not transmit at all, and a sufficient hydrostatic bearing effect is not produced and the friction force between the stacked media is not reduced sufficiently. 
     According to the embodiment, even when air permeability of media is low, air can flow between the stacked media  10  through the gap between the side surface of the piled stack of the media and the contact surface  41  of the support part  40 , so that it is possible to reduce the friction force between the stacked media  10  sufficiently. 
       FIGS. 4A and 4B  are views for explaining results obtained by measuring levitation heights using the device according to the embodiment. Sheets of thick paper were used for media in the measurement.  FIG. 4A  indicates a measurement position. Levitation heights of the sheets of thick paper shown in  FIG. 4A  were measured at eight points which were located along a longitudinal direction in paper surfaces of the sheets of thick paper.  FIG. 4B  shows distributions of measured levitation heights. One group of the sheets of thick paper (media) had a size of a postcard and had permeability. Another one group of the sheets of thick paper (media) had a size of a postcard and did not have permeability at vibration points of the sheets of thick paper because tapes were pasted on the vibration points of the sheets of thick paper. In a case that sheets of thick paper which do not have permeability are used, if one of the sheets of thick paper on an uppermost end side floats, it means that air flows in between the one of the sheets of thick paper on the uppermost end side and another one of the sheets of thick paper on a second uppermost end side, similarly to the case that the sheets of thick paper have permeability. 
     As illustrated in  FIG. 4B , expansion of surfaces of the sheets of thick paper was observed upon vibration, in both cases. This expansion is considered to have resulted from an inflow of air from side surfaces of the media. Thus, it was confirmed that inflow of air occurred from the side surfaces of the media even if the media did not have permeability. 
       FIGS. 5A to 5C  are views for explaining measurement results of friction force of the separating and taking out device according to the first embodiment. Pieces of film-coated paper which did not have permeability and had different thicknesses were used for media, and friction force of the pieces of film-coated paper was measured. The film-coated paper is a typical example of paper from which static electricity is likely to be produced and which is difficult to take out because the friction coefficient is unstable. 
       FIG. 5A  illustrates a measurement position. Measurement was performed by controlling friction force by placing a load on one uppermost end surface of the pieces of film-coated paper (media).  FIGS. 5B and 5C  illustrate results obtained by measuring inter-media friction force when the respective pieces of film-coated paper have 210 μm and 510 μm. According to the embodiment (data is indicated by “∘”), the vibration point was set above the gap  54 , and the inter-media friction force decreased. According to a comparative example (data is indicated by “Δ”), a vibration point was set above pieces of film-coated paper, and the inter-media friction force did not decrease sufficiently. Inter-media friction force of a case that vibration was not applied is also shown (data is indicated by “♦”). 
     The position of the ultrasonic vibrator  50  illustrated in  FIGS. 2 and 3  i.e. the vibration point of the ultrasonic vibrator  50  is desirably near a center of one of four sides of the media as illustrated in  FIGS. 4A and 5A . An experiment was conducted by using sheets of thick paper (media) having sizes of postcards and by changing the planar position of the ultrasonic vibrator  50  at four sides and four corners of the sheets of thick paper. When the planar position of the ultrasonic vibrator  50  was near the center of one side of the four sides, inflow of air became most remarkable and the sheets of thick paper (the media) floated so that the friction force decreased. In consideration that compressed air is produced from a surface of the ultrasonic vibrator  50 , it is most desirable from the view point of causing efficient inflow of air between the media to arrange the ultrasonic vibrator  50  in the center of one of the four sides 
     In  FIG. 2 , the gap  54  between the side surface of the piled stack  10   a  of the media  10  and the contact surface  41  of the support part  40  is desirably narrow. This is because air pressure can decrease and the pressure for lifting one of the media on an uppermost end becomes insufficient when the flow rate of the compressed air produced from the ultrasonic vibrator  50  is fixed and the gap  54  is large. The width of the gap  54  between the side surface of the one of the media  10  on the uppermost end and the contact surface  41  of the support part  40  is desirably 0.5 mm or less and, more preferably, is desirably 0.1 mm or less. In the experiment, the width of the gap between the side surface of the piled stack  10   a  and the contact surface  41  is uneven depending on types of media, and is in a range of 30 to 110 μm. A guide which supports the side surface on an opposite side of the contact surface  41  is desirably installed to keep the gap  54 , in order to prevent the media  10  from moving away from the contact surface  41 . Alternatively, it is desirable to have a configuration that the piled stack  10   a  is pressed against the contact surface  41  of the support part  40  by inclining an installation angle of the piled stack  10   a  and using the gravitational force. 
     The measuring unit  60  illustrated in  FIG. 1  is a sensor which measures a position of the top surface of the piled stack  10   a  of the media  10 , i.e., one of the media  10  on an uppermost end. The measuring unit  60  measures a distance h between the one of the media  10  on the uppermost end and a base surface such as a lower surface of the takeout roller  31 , in order to obtain the position of the media. An optical sensor, a contact sensor and a pressure sensor can be used for the measuring unit  60 . 
     In the moving unit  70  illustrated in  FIG. 1 , the moving base  71  supports the sheet feeding base  20  through the elastic structure  72  in the z axis direction, as described above. The rack  73  and the pinion  74  are provided to move the moving base  71  in the z axis direction. The rack  73  is attached to the moving base  71 . The pinion  74  is rotated by a motor (not illustrated). When the pinion  74  rotates in a direction of an arrow T 3 , the moving base  71  moves in a direction of an arrow T 4 . Following movement of the moving base  71 , the sheet feeding base  20  is moved through the elastic structure  72  in the z direction. Various driving structures can be used instead of the rack  73  and the pinion  74 . For example, a mechanism which drives the moving base  71  vertically using a ball screw can be used. Alternatively, a mechanism which drives the moving base  71  upward by a feeding mechanism with a torque limiter can be used. 
     The control unit  80  illustrated in  FIG. 1  is an arithmetic processing unit such as a CPU. The control unit  80  controls rotation of the pinion  74  of the moving unit  70  to align the position of one of the media  10  on an uppermost end in the z axis direction and the position of the top surface  42  of the support part  40  of  FIG. 2  in the z axis direction, based on the position of the one of the media  10  on the uppermost end measured by the measuring unit  60 . 
     Further, the control unit  80  controls the operation of the separating and taking out portion  30  i.e. rotations of the takeout roller  31  and the convey roller  32 , the operation of the ultrasonic vibrator  50  and the operation of the measuring unit  60 . 
     According to the embodiment, even when media which do not have permeability are used, the separating and taking out device  100  can reduce friction force between the stacked media  10 , and can separate and take out the media  10  one by one from the piled stack  10   a  more reliably. 
     As to the shape of the top surface  42  of the support part  40  of  FIG. 2 , it is sufficient that at least the portion of the top surface  42  which opposes to the vibration surface  51  is nearly parallel to the top surface of the piled stack  10   a , and the other portions of the top surface  42  may not be parallel to the top surface of the piled stack  10   a.    
     The opposing area S 1  of the vibration surface  51  and the top surface of the piled stack  10   a  may be larger than the opposing area S 2  of the vibration surface  51  and the top surface  42  of the support part  40 . In this case, the amount of air between the vibration surface  51  and the top surface of the piled stack  10   a  increases. Thus, it is possible to produce a traveling wave by vibration of the ultrasonic vibrator  50  efficiently. Further, the center of the vibration surface  51  at which the air pressure is the highest directly below the vibration surface  51  is closer to the top surface of the piled stack  10   a . Accordingly, the amplitude of the traveling wave produced by vibration of the ultrasonic vibrator  50  increases. As a result, it is possible to spread air which flows along the xy plane in between one of the media  10  on an uppermost end and another one of the media  10  on an second uppermost end, more efficiently. Consequently, when the media  10  are those of high rigidity such as metal films, for example, the embodiment is useful to separate the media  10 . 
     The opposing area S 1  of the vibration surface  51  and the top surface of the piled stack  10   a  of the media  10  may be smaller than the opposing area S 2  of the vibration surface  51  and the top surface  42  of the support part  40 . By reducing the opposing area S 1  of the vibration surface  51  and the top surface of the piled stack  10   a , it is possible to reduce the amplitude of the traveling wave produced by vibration of the ultrasonic vibrator  50 . In this case, it is also possible to reduce the friction force produced between the stacked media  10  by vibration, and suppress friction heat produced by the stacked media  10 . When the media  10  are plastic films, for example, which are weak against heat, the embodiment is useful to reduce friction force. 
     When taking out the media  10  from the piled stack  10   a , the separating and taking out device  100  of  FIG. 1  may take out each of the media  10  from an upper end in a direction opposite to the gravitational force direction which is a direction toward a lower surface side of the piled stack  10   a . Alternatively, the separating and taking out device  100  may take out each of the media  10  from an upper end positioned in the gravitation direction opposite to the direction of the lower surface side of the piled stack  10   a . Further, the separating and taking out device  100  may take out the media  10  such that the direction toward the side surface side of the piled stack  10   a  is a gravitational force direction and the top and bottom surfaces of the piled stack  10   a  are directed in the horizontal direction. 
     The separating and taking out device  100  may have two or more ultrasonic vibrators. In this case, it is also possible to provide ultrasonic vibrators with respect to the support part  40 , or to arrange two or more support parts so as to provide two or more ultrasonic vibrators  50  with respect to each of the support parts. As the number of ultrasonic vibratos is greater, the amount of air which flows in between the media  10  increases and an effect of levitation of the media  10  on an uppermost end increases so that it is possible to further reduce friction force. 
       FIG. 6  is a configuration diagram schematically illustrating a main portion of a separating and taking out device according to the second embodiment. 
     In  FIG. 6 , a separating and taking out device  200  has a cutout  44  at a position at which a top surface  42  of a support part  40  opposes to a vibration surface  51  of an ultrasonic vibrator  50 . The cutout  44  is provided to oppose to a nearly center of the vibration surface  51  of the ultrasonic vibrator  50 . This is because the highest acoustic radiation pressure is produced at the center of the ultrasonic vibrator  50 . According to this configuration, a ratio of an opposing area S 2  of the vibration surface  51  and the top surface  42  of the support part  40  with respect to an opposing area S 1  of the vibration surface  51  and a top surface of a piled stack  10   a  of media  10  increases. The opposing areas S 1  S 2  are obtained by projection in the z axis direction. 
       FIGS. 7A to 7C  are views for explaining measurement results obtained by measuring friction forces of pieces of film-coated paper (media) having different thicknesses.  FIG. 7A  illustrates vibration points of ultrasonic vibrators according to the second embodiment and a comparative example where the vibration point is set above the media.  FIG. 7B  illustrates a measurement result obtained by measuring friction force when the cutout  44  is not provided.  FIG. 7C  illustrates a measurement result obtained by measuring friction force when the cutout  44  is provided. The measurement results shown in  FIGS. 7B and 7C  include those according to the second embodiment, the comparative example and a case that the ultrasonic vibrator  50  is not oscillated, respectively. The measurement result of the embodiment is indicated by “∘”. The measurement result of a comparative example is indicated by “Δ”. The measurement result of a case that vibration was not applied is indicated by “♦”. 
     The cutout  44  is provided in the second embodiment as illustrated in  FIG. 6  and serves to function to supply compressed air to side surfaces of the media  10  through the cutout  44 . As a result, it is possible to supply the compressed air deeply in a depth direction irrespectively of the width of a gap  54  between the side surface of the piled stack  10   a  of the media and a contact surface  41  of the support part  40 . According to an experiment conducted by the inventors, by providing the cutout  44  which has a depth of 2 mm, the width of 0.3 mm and the length of 1 mm, an effect of reducing friction force between media having thicknesses of about 810 μm was obtained as illustrated in  FIG. 7C . As illustrated in  FIG. 7C , friction force did not decrease when a cutout is not provided. 
     The separating and taking out device  200  according to the embodiment can reduce the friction force between thicker media so that the number of types of applicable media increases. 
       FIG. 8  is a configuration diagram schematically illustrating a main portion of a separating and taking out device according to a third embodiment. 
     As illustrated in  FIG. 8 , in a separating and taking out device  300 , a concavity  45  is provided at an entire portion of a top surface  42  of a support part  40  which opposes to an ultrasonic vibrator  50 . Consequently, it is possible to position an entire vibration surface  51  of the ultrasonic vibrator  50  at a position lower than that of the top surface  42  of the support part  40 . According to the embodiment, in a case that media  10  are deformed upward with respect to the vibration surface  51  of the ultrasonic vibrator  50  due to warpage or concavities and convexities of shapes of the media  10 , it is possible to support side surfaces of the media  10  in order to prevent the side surfaces of the media  10  from reaching above the top surface  42  of the support part  40  and from being misaligned. 
       FIG. 9  is a configuration diagram schematically illustrating a main portion of a separating and taking out device according to a fourth embodiment. 
     As illustrated in  FIG. 9 , in a separating and taking out device  400 , a vibration surface  51  of an ultrasonic vibrator  50   a  has a step  52 . More specifically, a portion of the vibration surface  51  which opposes a top surface  42  of a support part  40  is lower in the z axis direction i.e. a vertical direction of  FIG. 9  than another portion of the vibration surface  51  which opposes the top surface of the piled stack  10   a  of the media  10 . The step  52  is provided so that it is possible to set the position where compressed air is produced to a position close to a side surface of a piled stack  10   a  of media  10 . Consequently, it is possible to cause an efficient inflow of air from the side surface of the piled stack  10   a.    
     The separating and taking out device described above can separate and take out media one by one from a piled stack of the media irrespectively of types of media, more reliably. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.