Abstract:
A swing apparatus for children and an oscillating device used in combination with a swing apparatus according to the present invention are aimed to solve the problems such as the motor is damaged due to overloaded current and a sitting device in the swing apparatus is stopped on a higher place when electric power is suddenly cut off. The oscillating device includes a base, a driving assembly mounted to the base, a first friction piece connected to the driving assembly, a second friction piece operatably driven by the first friction piece depending a friction force therebetween, an elastic piece urging against one of the first friction piece and the second friction piece, a first shaft passing through the transmitting assembly, and an output member cooperated by one of the first shaft and the second friction piece. The swing apparatus includes a first frame supported on the ground, a second frame in which the sitting device is mounted, and the oscillating device connecting the first frame to the second frame. The swing apparatus and the oscillating device make them possible that the motor will not be damaged due to overloaded current, the second frame may be gradually stopped and the sitting device may be stopped on a lower place when electric power is suddenly cut off.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to a swing apparatus for children and an oscillating device therein, and more particularly to a swing apparatus and an oscillating device driven by a friction piece. 
       BACKGROUND OF THE INVENTION 
       [0002]      FIG. 1  is a partially assembled view which illustrates a conventional swing assembly  1  for children disclosed in U.S. Pat. No. 6,872,146 B1. The rotor of a motor  10  in the  FIG. 1  is connected to a worm  11  which meshes with a worm gear  12 . One end of a sliding rod  13  is pivotally connected to one side face of the worm gear  12  and another end of the sliding rod  13  is pivotally connected to a pivoting piece  14 . The pivoting piece  14  is also used to secure one end of a spring  15 . 
         [0003]    When the motor  10  rotates, its movement is sequentially transmitted through the worm  11 , the worm gear  12 , the sliding rod  13  and the pivoting piece  14  to the spring  15 . Because another end of the spring  15  contacts the a stopper  16 , the restoration force resulting from deformation of the spring  15  is transmitted through the pivoting piece  14  and the sliding rod  13  to the worm gear  12  such that a swing rod  17  swings at a predetermined angle like a pendulum. Hence, a sitting device connected to the swing rod  17  at lower end thereof can be swung relative to a skeleton  18 . 
         [0004]    However, when the weight of the child in the sitting device exceeds the rated load of the motor  10 , the sitting device is blocked by miscellaneous articles from being swung, or another child outside the sitting device intentionally holds the sitting device, the sitting device looks stationary but the motor  10  is still electrically active. Therefore, the motor  10  will be damaged due to overloaded current. 
         [0005]    Besides, if outage happens or electric power is suddenly cut off when the sitting device is swung to a place other than the lowest position, the sitting device will fixedly stop at a relatively higher position immediately. This situation is similar to emergently braking a car, which causes the child in the sitting device to tilt forward or backward unexpectedly. In addition, the orientation of sitting device at that position makes the child therein uncomfortable 
         [0006]    Furthermore, the conventional swing assembly  1  is not equipped with a shielding device so that the conventional swing assembly  1  is not suitable for being used under the sun. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, the present invention relates to a swing apparatus for children and an oscillating device therein that are substantially intended to obviate one or more of the problems due to the limitations and disadvantages encountered in the prior art. 
         [0008]    One object of the present invention is to provide a swing apparatus for children and an oscillating device therein whose motor still can normally work to avoid from being damaged when the load on the seat frame exceeds rated capacity of the motor. 
         [0009]    Another object of the present invention is to provide a swing apparatus for children and an oscillating device therein which can cushion the movement of the seat frame and avoid sudden stop of the seat frame when electric power is suddenly cut off. 
         [0010]    Yet another object of the present invention is to provide a wing apparatus for children and an oscillating device therein which allow the seat frame to descend to a lower position when electric power is suddenly cut off. 
         [0011]    Further object of the present invention is to provide a wing apparatus for children which is suitable for being used under the sun. 
         [0012]    Additional features and advantages of the invention will be set forth in the description which follows, and in portion will be apparent from the description, or may be learned by practice of the invention. The objectives and advantages of the invention will be realized and attained by the structure as particularly set forth in the written description and claims as well as illustrated in the appended drawings. 
         [0013]    These objects are achieved by an oscillating device as defined by the claim  1  and a swing apparatus as defined by the claims  11  and  17 . The dependent claims define preferred or advantageous embodiments of the oscillating device and the swing apparatus. 
         [0014]    The present invention provides an oscillating device used in combination with a swing apparatus. The oscillating device comprises a base; a driving assembly mounted to the base; an output piece pivotally connected to the base, the driving assembly operatably driving the output piece to oscillate relative to the base; and a transmitting assembly which includes a first friction piece, the first friction piece is driven to oscillate back and forth by the driving assembly and moves relative to or together with the output piece depending on a friction force therebetween. 
         [0015]    Another aspect of the present invention is to provide a swing apparatus for children. The swing apparatus comprises a first frame, a second frame, and an oscillating device connecting the first frame with the second frame. The oscillating device includes: a base connected to the first frame; a driving assembly mounted to the base; an output piece pivotally connected to the base; and a transmitting assembly further including a first friction piece which is driven to oscillate back and forth by the driving assembly; whereby the first friction piece moves relative to or together with the output piece depending on a friction force therebetween, and the driving assembly operatably cooperates the second frame to swing relative to the first frame. 
         [0016]    Further aspect of the present invention is to provide a swing apparatus for children. The swing apparatus comprises: a first frame; a second frame; and an oscillating device connecting the first frame with the second frame, the oscillating device includes a base connected to the first frame, a driving assembly mounted to the base, an output piece secured to the second frame pivotally connected to the base, a transmitting assembly mounted between the driving assembly and the output piece, and a first shaft connected to the driving assembly and passing through the transmitting assembly; wherein the transmitting assembly includes a first friction piece secured to the first shaft, and a second friction piece un-rotatably connected to output piece; when the first shaft is driven to rotate relative to the base by the driving assembly, the first friction piece is moved together with the first shaft, and the second friction piece is driven to rotate relative to the base by the friction between the first friction piece and the second friction piece so that the second frame is driven to oscillate back and forth relative to the first frame. 
         [0017]    Moreover, the transmitting assembly includes a second friction piece which is for cooperating the output piece and an elastic piece which urges against one of the first friction piece and the second friction piece; the first friction piece moves relative to or together with the second friction piece depending on the friction force therebetween. 
         [0018]    In a preferred aspect, the first friction piece includes a first rough face and the second friction piece includes a second rough face; the first rough face faces the second rough face. 
         [0019]    It is another preferred feature that the first friction piece has a first friction face; the output piece has a second friction face which contacts the first friction face, the first friction face and the second friction face are cambered surfaces with different curvatures. 
         [0020]    Additionally, the oscillating device comprises a first shaft which passes through the transmitting assembly and has a first plane; the first friction piece further includes a first central orifice adapted to the first plane; the first shaft is received in the first central orifice such that the first friction piece and the first shaft move together. 
         [0021]    Furthermore, the driving assembly includes an actuator which is secured to the base, a driver which is connected to the actuator, a follower which is connected to the driver, and two links which are pivotally connected with each other and respectively connected to the follower and the first shaft; one of the two links includes a second central orifice adapted to the first plane; the first shaft is received in the second central orifice such that the one of the two links and the first shaft move together. 
         [0022]    It is preferred that the transmitting assembly further includes a packing with two opposite side faces which respectively contact the first rough face and the second rough face. 
         [0023]    It is preferred that the oscillating device further comprises a first shaft which passes through the transmitting assembly and has a first plane; the second friction piece further includes a third central orifice adapted to the first plane; the first shaft is received in the third central orifice such that the second friction piece and the first shaft move together. 
         [0024]    It is preferred that the first shaft includes a second plane; the output piece includes a fourth central orifice adapted to the second plane; the first shaft is received in the fourth central orifice such that the first shaft and the output piece move together. 
         [0025]    It is preferred that the driving assembly further includes an actuator which is secured to the base, a driver which is connected to the actuator, a follower which is connected to the driver, and a link which connects the follower to the first friction piece; the elastic piece urges against the first friction piece. 
         [0026]    It is preferred that the transmitting assembly further includes a second friction piece which is for cooperating the second frame and an elastic piece which urges against one of the first friction piece and the second friction piece; the first friction piece moves relative to or together with the second friction piece depending on the friction force therebetween. 
         [0027]    It is preferred that the swing apparatus further comprises a shielding device which is pivotally mounted to the oscillating device. 
         [0028]    It is preferred that the oscillating device further comprises a first shaft which passes through the transmitting assembly and has a first plane; the first friction piece further includes a first central orifice adapted to the first plane; the first shaft is received in the first central orifice such that the first friction piece and the first shaft move together. 
         [0029]    It is preferred that the oscillating device includes a second shaft and another base; the second shaft has a bent first section and the another base has two blockers; the bent first section moves between the two blockers so that the moving range of the second shaft and the output piece is restricted. 
         [0030]    It is preferred that the driving assembly includes a sensor which is secured to the base, an actuator which is secured to the base for supplying power to the transmitting assembly, a driver which is connected to the actuator, a follower which is connected to the driver, and a link device which are pivotally connected to the follower and a first shaft which passes through the transmitting assembly, the sensor is configured to sense the movement of the link device so as to control the output of the actuator. 
         [0031]    It is preferred that the first friction piece includes a first rough face and the second friction piece includes a second rough face; the transmitting assembly further includes a packing with two opposite side faces which respectively contact the first rough face and the second rough face. 
         [0032]    The swing apparatus and the oscillating device according to the present invention has the following advantages: the motor will not be damaged due to overloaded current, the second frame may be gradually stopped, the sitting device may be stopped on a lower place when electric power is suddenly cut off, and the swing apparatus is also suitable for being utilized under the sun. 
         [0033]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further non-limiting explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    The accompanying drawings, which are included to provide a further understanding of the invention and constitute a portion of the specification, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0035]      FIG. 1  is a partially assembled view illustrating a conventional swing assembly; 
           [0036]      FIG. 2  is an assembled prospective view illustrating a swing apparatus for children according to the present invention; 
           [0037]      FIG. 3  is an exploded prospective view illustrating an oscillating device (without the first cover) in the swing apparatus according to the first preferred embodiment of the present invention; 
           [0038]      FIG. 4  is an assembled prospective view illustrating the oscillating device (without the first cover) in the swing apparatus according to the first preferred embodiment of the present invention; 
           [0039]      FIG. 5  is an assembled side view illustrating the swing apparatus (without the first cover) according to the first preferred embodiment of the present invention, wherein the second frame is swung to a first (back) position; 
           [0040]      FIG. 6  is an enlarged view illustrating the oscillating device in the  FIG. 5 ; 
           [0041]      FIG. 7  is an assembled side view illustrating the swing apparatus (without a first cover) according to the first preferred embodiment of the present invention, wherein the second frame is swung to a second (forth) position; 
           [0042]      FIG. 8  is an enlarged view illustrating the oscillating device in the  FIG. 7 ; 
           [0043]      FIG. 9  is an exploded prospective view illustrating an oscillating device (without the first cover) in the swing apparatus according to the second preferred embodiment of the present invention; 
           [0044]      FIG. 10  is an assembled prospective view illustrating the second friction piece and output member shown in the  FIG. 9 ; 
           [0045]      FIG. 11  is a prospective view illustrating the output member shown in the  FIG. 9 ; 
           [0046]      FIG. 12  is an assembled side view illustrating the swing apparatus (without the first cover) according to the second preferred embodiment of the present invention, wherein the second frame is swung to a first (back) position; 
           [0047]      FIG. 13  is an enlarged view illustrating the oscillating device in the  FIG. 12 ; 
           [0048]      FIG. 14  is a side view illustrating the first friction piece meshes the second friction piece shown in the  FIG. 9 ; 
           [0049]      FIG. 15  is a side view illustrating the first friction piece does not mesh the second friction piece shown in the  FIG. 9 ; 
           [0050]      FIG. 16  is an assembled side view illustrating the swing apparatus (without the first cover) according to the second preferred embodiment of the present invention, wherein the second frame is swung to a second (forth) position; 
           [0051]      FIG. 17  is an enlarged view illustrating the oscillating device in the  FIG. 16 ; 
           [0052]      FIG. 18  is an exploded prospective view illustrating an oscillating device (without the first cover) in the swing apparatus according to the third preferred embodiment of the present invention; 
           [0053]      FIG. 19  is an exploded prospective view illustrating the output member and transmitting assembly shown in the  FIG. 18 ; 
           [0054]      FIG. 20  is an assembled prospective view of the first shaft, output member and transmitting assembly shown in the  FIG. 18 ; 
           [0055]      FIG. 21  is a side view of the  FIG. 20 ; 
           [0056]      FIG. 22  is a sectional view taken along line XXII-XXII in the  FIG. 21 ; 
           [0057]      FIG. 23  is an assembled prospective view illustrating a swing apparatus for children according to the fourth embodiment of the present invention; 
           [0058]      FIG. 24  is a front view illustrating the oscillating device, in which the first cover is not shown, in one side of the swing apparatus for children according to the fourth embodiment of the present invention; 
           [0059]      FIG. 25  is an exploded perspective view illustrating the driving assembly of the oscillating device in one side of the swing apparatus for children according to the fourth embodiment of the present invention; 
           [0060]      FIG. 26  is an exploded perspective view illustrating the transmitting assembly of the oscillating device in one side of the swing apparatus for children according to the fourth embodiment of the present invention; 
           [0061]      FIG. 27  is an exploded perspective view illustrating the shielding device shown in the  FIG. 23 ; 
           [0062]      FIG. 28  is a partially sectional assembled view illustrating the oscillating device in one side of the  FIG. 23 ; 
           [0063]      FIG. 29  is an exploded perspective view illustrating the driving assembly of the oscillating device in another side of the swing apparatus for children according to the fourth embodiment of the present invention; 
           [0064]      FIG. 30  is a partially sectional assembled view illustrating the oscillating device in another side of the  FIG. 23 ; and 
           [0065]      FIG. 31  is an assembled front view illustrating the base and the second shaft in the  FIG. 29 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The First Preferred Embodiment 
       [0066]    As shown in  FIGS. 2 and 3 , the swing apparatus  2  for children according to the first preferred embodiment of the present invention comprises a first frame  3 , a second frame  4  and an oscillating device  5 . The first frame  3  may include two U-shaped frame bodies. 
         [0067]    The oscillating device  5  connects the first frame  3  with the second frame  4 . The second frame  4  may further include a seat portion  40 , a backrest  41  and a hanger arm  42 , which are connected with one another. Soft good or a sitting device (not shown) is fixed to the seat portion  40  and the backrest  41  for a child to sit in. 
         [0068]    The oscillating device  5  includes a base  50 , a driving assembly  51 , a transmitting assembly  52 , a first shaft  53 , an output member  54 , two supporting pieces (such as bearings)  55 , a second cover  56 , a washer  57 , a retainer (such as a plum-blossom-shaped washer)  58  and a first cover  59 . 
         [0069]    The base  50  has a cuff  500  with about three-fourth circle near upper end and a hole  501  at the center of the circle. 
         [0070]    The driving assembly  51  further includes an actuator (such as a motor)  510  fixed to the base  50 , a driver (such as a worm)  511  connected to or used as the rotor of the actuator  510 , a follower (such as a worm gear)  512  engaged with the driver  511 , and a link  513 . 
         [0071]    The transmitting assembly  52  further includes an elastic piece (such as a spring)  523 , a first friction piece  520 , a packing  521  and a second friction piece  522 , which are sequentially distributed. 
         [0072]    The first friction piece  520  includes an ear  525  extending away from the circumference thereof, and a first rough face  526  situated at one side thereof. 
         [0073]    The second friction piece  522  includes two opposite fourth planes  527  formed in the central orifice thereof, and a second rough face  528  situated at one side thereof. 
         [0074]    The first shaft  53 , according to the sizes of diameters, includes a first section  531  as a head portion, a second section  532  with two opposite second planes  537  within full length, a third section  533  with two opposite first planes  538  within partial length, a fourth section  534  with the smallest diameter, and a fifth section  535  as a tail portion. 
         [0075]    Assembling 
         [0076]    As shown in  FIGS. 3 and 4 , the first shaft  53  is inserted into the output member  54  through the central orifice thereof first. Because the output member  54  has two opposite third planes  543  in the central orifice thereof, the second planes  537  of the second section  532  will abut against the third planes  543  so that the output member  54  and the first shaft  53  are unable to rotate relative to each other. 
         [0077]    Next, the subassembly of the output member  54  and the first shaft  53  is mounted to the base  50 . Specifically, The third section  533  of the first shaft  53  passes through the hole  510  of the upper portion of the base  50  so that the output member  54  and the third section  533  of the first shaft  53  are respectively situated at two opposite sides of the base  50 . 
         [0078]    Thereafter, one of the supporting pieces  55  is put into the cuff  500  and sleeved on the first shaft  53  at the third section  533  other than the first planes  538 . Subsequently, the second friction piece  522 , the packing  521 , the first friction piece  520 , elastic piece  523 , another supporting piece  55 , the second cover  56 , and the washer  57 , each with a central orifice, are sequentially sleeved on the third section  533  at the portion of the first planes  538 . Among the elements sleeved on the first planes  538 , only the second friction piece  522  is provided with two opposite fourth planes  527  within the central orifice thereof, which aims at being engaged with the first planes  538  of the first shaft  53 . In view of this, the second friction piece  522  and the first shaft  53  is unable to rotate relative to each other while the packing  521 , the first friction piece  520  and the elastic piece  523  can rotate relative to the first shaft  53 . 
         [0079]    Finally, the retainer  58  is snapped on the first shaft  53  at the fourth section  534  such that all elements sleeved on the first shaft  53  cannot be released from the first shaft  53  and the base  50 . 
         [0080]    On the other hand, the actuator  510  is secured to the base  50  at the lower portion. After that, the follower  512  is pivotally connected to the base  50  and engaged with the driver  511 . Then, two ends of the link  513  are pivotally connected respectively to the other side of the follower  512  and the ear  525  of the first friction piece  520 . 
         [0081]    Moreover, the first cover  59  with electric switches  590  is installed to the base  50  and thus the assembling about the oscillating device  5  in the swing apparatus  2  for children is accomplished. 
         [0082]    As shown in the  FIG. 2 , if the first frame  3  is further mounted below the base  50  and the hanger arm  42  of the second frame  4  is fastened to the output member  54 , then the swing apparatus  2  for children according to the present invention is totally assembled. Incidentally, the swing apparatus  2  may be equipped with, for example, only one complete oscillating device  5  at one side of the swing apparatus  2 , i.e., another oscillating device  5  at another side of the swing apparatus  2  does not include the driving assembly  51  and the transmitting assembly  52 . 
         [0083]    Operation and Effect 
         [0084]    As shown in  FIGS. 3 ,  5  and  6 , when one of the electric switches  590  ( FIG. 2 ) is pressed, electric current flows through electric circuit (not shown) to start the actuator  510 . The movement of the actuator  510  is sequentially transmitted to the driver  511 , the follower  512 , link  513 , and the first friction piece  520 . In the meantime, the follower  512  continuously rotates in one direction while the first friction piece  520  can only repeatedly oscillates within a predetermined angular range. 
         [0085]    Furthermore, since the first rough face  526  of the first friction piece  520  and the second rough face  528  of the second friction piece  522  respectively face two sides of the packing  521 , the first friction piece  520  and the second friction piece  522  will tightly abut respectively against the two side faces of the packing  521  due to elastic force of the elastic piece  523 . Consequently, the oscillating movement of the first friction piece  520  can be transmitted to the packing  521  and further to the second friction piece  522  by means of the friction forces existing on the faces contacting each other. When the load, which may include weights of the second frame  4 , sitting device, child and miscellaneous articles, on the second frame  4  is smaller than the friction force in the transmitting assembly  52 , the first friction piece  520 , the packing  521  and the second friction piece  522  shall not rotate relatively one another. 
         [0086]    Because the fourth plane  527  of the second friction piece  522  matches the first plane  538  of the first shaft  53 , oscillating movement of the second friction piece  522  can be transmitted to the first shaft  53 . Similarly, the movement of the first shaft  53  can be transmitted to the output member  54  since the second plane  537  of the first shaft  53  matches the third plane  543  of the output member  54 . The output member  54  is allowed to oscillate relative to the base.  50  and then the movement of the output member  54  is transmitted to the second frame  4  via the hanger arm  42 . As a result, the second frame  4  and the sitting device thereon can swing back and forth within a predetermined angular range, such as the first (back) position illustrated in the  FIG. 5  and the second (forth) position illustrated in the  FIG. 7 . Incidentally, the two supporting pieces  55  are used to support the first shaft  53  respectively at two ends thereof to help the oscillation movement smoother. 
         [0087]    In the transmitting assembly  52  of the present invention, the first rough face  526 , the packing  521  and the second rough face  528  have friction coefficients depending on material and roughness thereof so that when the elastic piece  523  applies normal force to the first friction piece  520 , there are friction forces on the contacting faces during oscillating movement. Therefore, if the load on the second frame  4  is smaller than the maximum static friction force on the contacting faces, the movement of the driving assembly  51  can be transmitted through the transmitting assembly  52  to the output member  54  so as to swing the second frame  4 . Specifically, when the load on the second frame  4  is smaller than the maximum static friction force between the first friction piece  520  and the packing  521 , the link  513  drives the first friction piece  520  and then the first friction piece  520  frictionally drives the packing  521  via the friction force. When the load on the second frame  4  is also smaller than the maximum static friction force between the packing  521  and the second friction piece  522 , the packing  521  also frictionally drives the second friction piece  522  via the friction force. The second friction piece  522  further cooperates the first shaft  53  so that the output member  54  is co-moved by the first shaft  53 . 
         [0088]    On the contrary, when the load on the second frame  4  is larger than the maximum static friction force among the first rough face  526 , the packing  520  and the second rough face  528 , then the first friction piece  520  will rotate relative to the packing  521  and/or the packing  521  will rotate relative to the second friction piece  522 . In other words, the second friction piece  522  is stationary. In this case, although the driving assembly  51  continuously operates, the movement thereof can only be transmitted to the first friction piece  520  or even to the packing  521  but by no means to the second friction piece  522 . Hence, the second friction piece  522 , the first shaft  53 , the output member  54  and the second frame  4  are all stationary. Because the actuator  510  is kept in normally operating state at this time, it will not break down due to overload. 
         [0089]    In another aspect, if blackout happens or the power is suddenly switched off during oscillation of the second frame  4 , on the ground that resultant force of the normal load and inertia force of the second frame  4  is larger than the maximum friction force, the first friction piece  520 , the packing  521  or the second friction piece  522  may rotate relatively one another so that the second frame  4  may swing further by a small angle rather than suddenly stop like emergently braking a car. Besides, the maximum static friction force on the contacting faces turns into smaller kinetic friction force, which may be also smaller than the load on the second frame  4 , such that the second friction piece  522  perhaps rotate relative to the packing  521  or the first friction piece  520  due to the load itself on the second frame  4  and thus the second frame  4  may gradually descend near the lowest position. 
         [0090]    The material of the packing  521  may be rubber, the packing  521  may be omitted from the transmitting assembly  52  in another embodiment, and the first and second friction pieces  520 ,  522  may be respectively made of different materials, all of which can achieve the objects and effects according to the present invention. 
       The Second Preferred Embodiment 
       [0091]    The difference between the swing apparatuses  2  of the first and second preferred embodiments of the present application only exists in some structure and assembling process of the oscillating device  5 . As to the first frame  3  and the second frame  4 , the two embodiments have the same structure and assembling process. Therefore, only the difference is described in the following second embodiment. 
         [0092]    As shown in the  FIG. 9 , the oscillating device S in the second preferred embodiment includes a base  50 , a driving assembly  51 , a transmitting assembly  52 , a first shaft  53 , an output member  54 , three supporting pieces (such as bearings)  55 , a second cover  56 , a washer  57 , a retainer (such as a plum-blossom-shaped washer)  58  and a first cover  59  ( FIG. 2 ). 
         [0093]    The base  50  has a cuff  500  with about three-fourth circle near upper end, a hole  501  at the center of the circle, and a pillar  502  formed at the center of the base  50 . 
         [0094]    The driving assembly  51  includes an actuator (such as a motor)  510  fixed to the base  50 , a driver (such as a worm)  511  connected to or used as the rotor of the actuator  510 , a follower (such as a worm gear)  512  engaged with the driver  511 , a first link  514  pivotally connected to the follower  512 , and one end of a second link  515  pivotally connected to the first link  514 . The second link  515  at the other end thereof has a bore and two opposite sixth planes  517  within the bore. 
         [0095]    The transmitting assembly  52  includes a first friction piece  520 , a second friction piece  522  and an elastic piece (such as a spring)  523 , which are sequentially distributed. The first friction piece  520  has two opposite fifth planes  5201  formed in the central orifice thereof and a first tooth face  5202  (functioning as the first rough face) formed on one side face thereof. The second friction piece  522  has a second tooth face  5221  (functioning as the second rough face) formed on one side face thereof, a plurality of flanges  5222  ( FIG. 10 ) extending from opposite side thereof and distributed in a ring shape, and a plurality of slots  5223  ( FIG. 10 ) respectively defined by any two adjacent flanges  5222 . Both the first tooth face  5202  and second tooth face  5221  have a plurality of crown teeth distributed radically. 
         [0096]    The first shaft  53 , according to the sizes of diameters, includes a first section  531  functioning as a head portion, a second section  532  without any plane within full length, a third section  533  with two opposite first planes  538  within full length, a fourth section  534  with the smallest diameter, and a fifth section  535  functioning as a tail portion. The second section  532  and the cylindrical portion of the third section  533  have the same diameter. 
         [0097]    The output member  54  has a plurality of ribs  544  ( FIG. 11 ) radically distributed around the central orifice thereof but there is no the third plane  543  in the first embodiment within the central orifice. 
         [0098]    The second cover  56  includes a cap  561 , a plate  562  extending away from the cap  561 , and an aperture  563  formed in the free end of plate  562 . 
         [0099]    Assembling 
         [0100]    At first, the first shaft  53  is inserted into the output member  54  through the central orifice thereof. Next, the first supporting piece  55 , the elastic piece  523 , the second friction piece  522  and the first friction piece  520  are sequentially sleeved on the first shaft  53  such that two ends of the elastic piece  523  respectively urge against the output member  54  and the second friction piece  522  at its side with the flange  5222 , and such that the second tooth face  5221  of the second friction piece  522  abuts against the first tooth face  5202  of the first friction piece  520 . Thereafter, the first shaft  53  in the subassembly described above is inserted into the hole  501  of the base  50  so that the output member  54 , the first supporting piece  55 , the elastic piece  523 , the second friction piece  522  and the first friction piece  520  are positioned at one side of the base  50 , while part of the third section  533 , the fourth section  534  and the fifth section  535  of the first shaft  53  are situated at another side of the base  50  and received within the cuff  500 . 
         [0101]    Subsequently, the second supporting piece  55 , one end of the second link  515  with the sixth plane  517 , the third supporting piece  55 , the cap  561  of the second cover  56 , the washer  57  and the retainer  58  are sequentially sleeved on the first shaft  53 . Among the elements that are mounted on the first shaft  53 , except that the output member  54  and the first supporting piece  55  are sleeved on the second section  532  of the first shaft  53  and the retainer  58  clips the first shaft  53  at the fourth section  534 , the others are sleeved on the first shaft  53  at the third section  533 . In addition, the pillar  502  of the base  50  is accommodated within the aperture  563  of the second cover  56 . 
         [0102]    Nevertheless, among the elements that are mounted on the first shaft  53 , only the second link  515  with the sixth plane  517  and the first friction piece  520  with the fifth plane  5201  abut against the first plane  538  of the first shaft  53 . Accordingly, the first shaft  53  will always move together with the second link  515  as well as the first friction piece  520 . As far as the other elements mounted on the first shaft  53 , because they have no planes to abut against the first plane  538  of the first shaft  53 , the first shaft  53  can rotate relative to them. 
         [0103]    On the other hand, the actuator  510  is secured to the lower portion of the base  50 . After that, the follower  512  is pivotally connected to the base  50  and engaged with the driver  511 . Then, two ends of the first link  514  are pivotally connected respectively to a side face of the follower  512  and another end of the second link  515 . 
         [0104]    Moreover, the first cover  59  with the electric switches  590  is installed to the base  50  and secured to the pillar  502 . The assembling about the oscillating device  5  in the swing apparatus  2  for children is now accomplished. 
         [0105]    Operation and Effect 
         [0106]    As shown in  FIGS. 9 ,  12  and  13 , when one of the electric switches  590  ( FIG. 2 ) is pressed, electric current flows through electric circuit (not shown) to start the actuator  510 . The movement of the actuator  510  is sequentially transmitted to the driver  511 , the follower  512 , the first link  514 , the second link  515 , the first shaft  53  and the first friction piece  520 . In the meantime, the follower  512  continuously rotates in one direction while the first friction piece  520  can only repeatedly oscillates within a predetermined angular range. 
         [0107]    Furthermore, the corresponding crown teeth on the first tooth face  5202  of the first friction piece  520  and the second tooth face  5221  of the second friction piece  522  will tightly mesh each other due to elastic force of the elastic piece  523 . Specifically, as shown in the  FIG. 14 , the tooth ends and root ends on the first tooth face  5202  of the first friction piece  520  respectively abut against the root ends and tooth ends on the second tooth face  5221  of the second friction piece  522 , and the tooth flanks on the first tooth face  5202  abut against the tooth flanks on the second tooth face  5221 . Consequently, when the load, which may includes weights of the second frame  4 , sitting device, child and miscellaneous articles, on the second frame  4  is smaller than the meshing force of friction force between corresponding crown teeth in the transmitting assembly  52 , the first friction piece  520  and the second friction piece  522  cannot rotate relative to each other so that the movement of the first friction piece  520  can be transmitted to the second friction piece  522 . Furthermore, because the ribs  544  of the output member  54  are respectively accommodated within the slots  5223  on another side face of the second friction piece  522  and almost abut against the flanges  5222  ( FIG. 10 ), the movement of the second friction piece  522  can be transmitted to the output member  54 . 
         [0108]    The output member  54  can rotate relative to the base  50 . The oscillation movement of the output member  54  can be transmitted to the second frame  4  via the hanger arm  42  in order to make the second frame  4  and the sitting device secured thereon swing back and forth within a predetermined angular range, such as the first (back) position illustrated in the  FIG. 12  and the second (forth) position illustrated in the  FIG. 16 . Incidentally, the three supporting pieces  55  are used to support the first shaft  53  respectively at two ends and middle portion thereof to help the oscillation movement smoother. 
         [0109]    On the contrary, when the load on the second frame  4  is larger than the meshing force or maximum static friction force between the first tooth face  5202  and the second tooth face  5221 , then the first friction piece  520  will rotate relative to the second friction piece  522 . In other words, as shown in the  FIG. 15 , the tooth flanks on the first tooth face  5202  slide relative to the tooth flanks on the second tooth face  5221  to the extent that the tooth ends on the first tooth face  5202  contact the tooth ends on the second tooth face  5221 . At the same time, the second friction piece  522  is further pressed into the output member  54 , i.e., the ribs  544  of the output member  54  are further inserted into the slots  5223  in the second friction piece  522 , so that the gap  545  between the second friction piece  522  and the output member  54  is decreased. When the first friction piece  520  keeps rotating, the states shown in the  FIGS. 14 and 15  alternatively appear such that the second friction piece  522  can only slide back and forth along the first shaft  53  but cannot rotate together with the first shaft  53 . In this case, although the driving assembly  51  continuously operates, the movement thereof can only be transmitted through the first shaft  53  to the first friction piece  520  to make the first friction piece  520  swing within a predetermined angular range. Instead, the second friction piece  522  can only reciprocate in the axial direction of the first shaft  53  within a short distance but cannot be rotated by the first friction piece  520 . As to the output member  54  and the second frame  4  are all stationary. Because the actuator  510  is kept in normally operating state at this time, it will not break down due to overload. 
         [0110]    In another aspect, if blackout happens or the power is suddenly switched off during oscillation of the second frame  4 , on the ground that resultant force of the normal load and inertia force of the second frame  4  is larger than the meshing force or maximum static friction force between the first tooth face  5202  and the second tooth face  5221 , the second friction piece  522  may rotate relative to the first friction piece  520  a little bit regardless of the stop of the first friction piece  520 . Therefore, the second frame  4  may swing further by a small angle rather than suddenly stop like emergently braking a car. Besides, the maximum static friction force on the tooth flanks of the crown teeth turns into smaller kinetic friction force, which may be also smaller than the load on the second frame  4 , such that the second friction piece  522  perhaps rotate relative to the first friction piece  520  due to the load itself on the second frame  4  and thus the second frame  4  may gradually descend to the lower position. 
       The Third Preferred Embodiment 
       [0111]    The difference between the swing apparatuses  2  of the third and second preferred embodiments of the present application only exists in some structure and assembling process of the oscillating device  5 . As to the first frame  3  and the second frame  4 , their structure and assembling process are the same as those in the first and second embodiments. Therefore, only the difference is described in the following third embodiment. 
         [0112]    As shown in the  FIG. 18 , the oscillating device  5  in the third embodiment includes a base  50  (the same as that in the  FIG. 9 ), a driving assembly  51  (the same as that in the  FIG. 9 ), a transmitting assembly  52 , a first shaft  53 (the same as that in the  FIG. 9 ), an output member  54 , two supporting pieces (such as bearings)  55  ( FIG. 9 ), a second cover  56  (the same as that in the  FIG. 9 ), a washer  57  (the same as that in the  FIG. 9 ), a retainer (such as plum-blossom-shaped washer)  58  (the same as that in the  FIG. 9 ) and a first cover  59  ( FIG. 2 ). 
         [0113]    As shown in the  FIG. 19 , the transmitting assembly  52  includes a substantially cap-shaped first friction piece  520 . The first friction piece  520  has a first wall  5205  with a larger curvature radius, a second wall  5206  with a smaller curvature radius, a pair of parallel fifth planes  5201  formed the central orifice thereof, and a first friction plane  5207  (functioning as a first rough face) situated at the inner side of the first wall  5205 . In addition, the first wall  5205  and the second wall  5206  are joined with each other to form a closed loop. The first friction face  5207  is made of rubber or a rubber pad. 
         [0114]    The output member  54  includes an inner first bush  546 , an outer second bush  547  substantially concentric with the first bush  546 , and a second friction face  548  formed on the lower half outer portion of the first bush  546  and functioning as a second rough face. The output member  54  in the third preferred embodiment additionally has the friction function the same as that of the second friction piece  522  in the first and second embodiments. 
         [0115]    The curvatures (or curvature radiuses) of the first wall  5205 , the second wall  5206 , the first bush  546  and the second bush  547  are different from one another. 
         [0116]    Assembling 
         [0117]    As shown in the  FIGS. 18 ,  19  and  20 , at first, the first friction face  5207  of the first friction piece  520  is substantially aligned with the second friction face  548  of the output member  54 . Then, the first and second walls  5205 ,  5206  of the first friction piece  520  are put into a space between the first and second bush  546 ,  547  of the output member  54 . Next, the first shaft  53  is sequentially inserted into the central orifices of the output member  54  and the first friction piece  520  to the extent that the first plane  538  of the first shaft  53  faces the fifth plane  5201  of the first friction piece  520 . At this time, the first friction face  5207  of the first friction piece  520  frictionally contacts the second friction face  548  of the output member  54 . Thereafter, the subassembly described above is mounted to base  50  and the driving assembly  51 , where the mounting processes are the same as those in the second preferred embodiments. 
         [0118]    Operation and Effect 
         [0119]    As shown in  FIGS. 18 ,  21  and  22 , when one of the electric switches  590  ( FIG. 2 ) is pressed, the movement of the driving assembly  51  is transmitted to the first shaft  53  to make the first shaft  53  rotate in a predetermined angular range. Because the first plane  538  of the first shaft  53  abuts against the fifth plane  5201  of the first friction piece  520 , the first shaft  53  will co-rotate with the first friction piece  520  and cannot rotate alone relative to the first friction piece  520 . Furthermore, since the first friction face  5207  frictionally contacts the second friction face  548 , the first friction piece  520  will move together with the output member  54  when the load on the second frame  4  is smaller than the friction force between the first friction face  5207  and the second friction face  548 . Hence, the second frame  4  can be swung by the output member  54 . 
         [0120]    On the contrary, when the load on the second frame  4  is larger than the friction force between the first friction face  5207  and the second friction face  548 , then the first friction piece  520  will rotate relative to the output member  54 . Therefore, although the driving assembly  51  continuously cooperates with the first shaft  53  and the first friction  520 , the output member  54  and the second frame  4  are still stationary. Because the actuator  510  is kept in normally operating state at this time, it will not break down due to overload. 
       The Fourth Preferred Embodiment 
       [0121]    As shown in the  FIG. 23 , the swing apparatus  2  for children according to the fourth preferred embodiment, which is more similar to the second embodiment, of the present invention comprises a first frame  3 , a second frame  4 , an oscillating device  5  and a shielding device  7 . The first frame  3  may include two U-shaped frame bodies. The oscillating device  5  connects the first frame  3  with the second frame  4 . 
         [0122]    The second frame  4  is similar to that described in the first preferred embodiment ( FIG. 2 ). 
         [0123]    As shown in the  FIGS. 24 ,  25  and  26 , The oscillating device  5  includes a base  50 , a driving assembly  51 , a transmitting assembly  52 , a first shaft  53 , an output member  54 , three supporting pieces (such as bearings)  55 , a second cover  56 , a washer  57 , a retainer (such as a plum-blossom-shaped washer)  58 , a first cover  59  ( FIG. 23 ) and two sealing pieces  61 . 
         [0124]    The base  50  has a cuff  500  with about three-fourth circle near upper end, a hole  501  at the center of the circle, an annulus  503  ( FIG. 28 ) formed on another side opposite to the side with the cuff  500 , and a plurality of bulges  504  ( FIG. 28 ) extending away from the outer surface of the annulus  503 . 
         [0125]    As shown in the  FIG. 25 , the driving assembly  51  further includes an actuator (such as a motor)  510  fixed to the base  50 , a driver (such as a worm)  511  connected to or used as the rotor of the actuator  510 , a follower (such as a worm gear)  512  engaged with the driver  511 , a first link  514  pivotally connected to the follower  512 , a second link  515  pivotally connected to the first link  514 , and a sensor  516  installed near the joint where the first link  514  pivotally connects with the second link  515 . The second link  515  has two fingers  519  extending from the joint and a trough  518  near the joint for pivotally connecting with the first link  514 . The second link  515  at another end thereof has a bore and two opposite sixth planes  517  within the bore. 
         [0126]    As shown in the  FIG. 26 , the transmitting assembly  52  further includes a first friction piece  520 , a packing  521 , a second friction piece  522  and an elastic piece (such as a spring)  523 , which are sequentially distributed. 
         [0127]    The first shaft  53  is similar to that described in the second preferred embodiments ( FIG. 9 ). 
         [0128]    The first friction piece  520  includes two opposite fifth planes  5201  formed in the central orifice thereof and a first rough face  526  formed on one side face thereof. The second friction piece  522  includes a second rough face  528  formed on one side face thereof, a plurality of flanges  5222  ( FIG. 10 ) extending from opposite side thereof and distributed in a ring shape, and a plurality of slots  5223  ( FIG. 10 ) respectively defined by any two adjacent flanges  5222 . 
         [0129]    As showing in the  FIG. 27 , the shielding device  7  includes a gripper  71 , a holder  72  and a canopy  73 . The canopy  73  has two cutouts  731  respectively formed at two opposite ends thereof. 
         [0130]    The gripper  71  has a ring-like housing  711 , a port  714  formed in one end of the housing  711 , a window  715  communicating with the port  714 , two gripping portions  712  extending inwards from the end of the housing  711 , a plurality of notches  716  formed on one side of each gripping portions  712 , and a curved flute  713  formed at another end of the housing  711 . 
         [0131]    The holder  72  has a first holding piece  721 , a second holding piece  722 , a stiffener  723  formed on the top face of the first holding piece  721 , a plug  724  extending away from the bottom face of the first holding piece  721 , and a bump  725  formed on the side face of the plug  724 . 
         [0132]    Assembling of the Oscillating Device 
         [0133]    As shown in the  FIGS. 26 and 28 , at first, the first shaft  53  is inserted into the output member  54  through the central orifice thereof. Next, the first supporting piece  55 , the elastic piece  523 , the second friction piece  522 , the packing  521 , the first friction piece  520  and the gripper  71  are sequentially sleeved on the first shaft  53  such that two ends of the elastic piece  523  respectively urge against the output member  54  and the second friction piece  522  at its side with the flanges  5222 . Thereafter, the first shaft  53  in the subassembly described above is inserted into the hole  501  of the base  50  to the extent that the output member  54 , the first supporting piece  55 , the elastic piece  523 , the second friction piece  522 , the packing  521 , the first friction piece  520  and the gripper  71  are positioned at one side of the base  50  while part of the third section  533 , the fourth section  534  and the fifth section  535  of the first shaft  53  are situated at another side of the base  50  and received within the cuff  500 . 
         [0134]    As shown in the  FIGS. 24 ,  25  and  28 , subsequently, the second supporting piece  55 , one end of the second link  515  with the sixth plane  517 , the third supporting piece  55 , the cap  561  of the second cover  56 , the washer  57  and the retainer  58  are sequentially sleeved on the first shaft  53 . Among the elements that are mounted on the first shaft  53 , except that the output member  54 , the first supporting piece  55 , the elastic piece  523 , the second friction piece  522  and the packing  521  are sleeved on the second section  532  of the first shaft  53  and the retainer  58  clips the first shaft  53  at the fourth section  534 , the others are substantially sleeved on the first shaft  53  at the third section  533 . In addition, the pillar  502  of the base  50  is accommodated within the aperture  563  of the second cover  56 . 
         [0135]    As shown in the  FIGS. 25 ,  26  and  28 , among the elements that are mounted on the first shaft  53 , only the second link  515  with the sixth plane  517  and the first friction piece  520  with the fifth plane  5201  abut against the first plane  538  of the first shaft  53 . Accordingly, the first shaft  53  will always move together with the second link  515  as well as the first friction piece  520 . As far as the other elements mounted on the first shaft  53 , because they have no planes to abut against the first plane  538  of the first shaft  53 , the first shaft  53  can rotate relative to them. 
         [0136]    As shown in the  FIGS. 24 and 25 , on the other hand, the sensor  516  and actuator  510  are respectively secured to the base  50 . After that, the follower  512  is pivotally connected to the base  50  and engaged with the driver  511 . Then, two ends of the first link  514  are pivotally connected respectively to a side face of the follower  512  and within the trough  518  of the second link  515 . 
         [0137]    Moreover, the sealing pieces  61 , which reduce the clearance between the base  50  and the first cover  59 , are mounted respectively on the base  50  and the first cover  59 . The first cover  59  with the electric switches  590  is installed to the base  50  and secured to the pillar  502 . The assembling about the oscillating device  5  in the swing apparatus  2  for children is now accomplished. 
         [0138]    Assembling of the Shielding Device 
         [0139]    As shown in the  FIG. 27 , the plugs  724  of the first holding pieces  721  are respectively inserted into the ports  714  of the grippers  71  so that the bumps  725  on the plugs  724  are respectively accommodated within the windows  715  of the grippers  71 . Next, two ends of the canopy  73  are respectively set on the first holding pieces  721  so that the stiffener  723  on the first holding piece  721  are received within the cutouts  731  of the canopy  73 . After the second holding pieces  722  are placed on the canopy  73  near the cutouts  731 , the second holding piece  722 , the canopy  73  and the first holding piece  721  are fixed together by a fastener (not shown) such as a screw or rivet. The shielding device  7  in the swing apparatus  2  for children is thus completed and the shielding device  5  is pivotally mounted on the oscillating device  5  at the same time. Alternatively, the second holding piece  722  can be omitted and the canopy  73  is directly secured onto the first holding piece  721 . Alternatively, the holder  72  and the gripper  71  may be integrally formed. 
         [0140]    As shown in the  FIGS. 23 and 2 , one swing apparatus  2  may be alternatively equipped with two different oscillating devices  5  at two sides thereof. One of the oscillating devices  5  has been described above. Another oscillating device  5  may not includes the driving assembly  51  ( FIG. 9 ) and the transmitting assembly  52  ( FIG. 24 ) but does includes a base  50  and a second shaft  53 ′ different from those described above. As shown in the  FIG. 29 , the first section  531  of the second shaft  53 ′ is bent to be a U shape relative to the second section  532 . As to the base  50 , it may further include two blockers  506  extending away from the cuff  500  and spaced apart at a predetermined angle, such as  30  degrees. 
         [0141]    Operation and Effect 
         [0142]    As shown in the  FIGS. 25 and 26 , when one of the electric switches  590  ( FIG. 23 ) is pressed, electric current flows through electric circuit (not shown) to start the actuator  510 . The movement of the actuator  510  is sequentially transmitted to the driver  511 , the follower  512 , the first link  514 , the second link  515  and the first friction piece  520 . In the meantime, the follower  512  continuously rotates in one direction while the first friction piece  520  can only repeatedly oscillates within a predetermined angular range. 
         [0143]    Furthermore, since the first rough face  526  of the first friction piece  520  and the second rough face  528  of the second friction piece  522  respectively face two sides of the packing  521 , the first friction piece  520  and the second friction piece  522  will tightly abut respectively against the two side faces of the packing  521  due to elastic force of the elastic piece  523 . Consequently, the oscillating movement of the first friction piece  520  can be transmitted to the packing  521  and further to the second friction piece  522  by means of the friction forces existing on the faces contacting each other. When the load on the second frame  4  is smaller than the friction force in the transmitting assembly  52 , the first friction piece  520 , the packing  521  and the second friction piece  522  shall not rotate relatively one another. Therefore, the movement of the first friction piece  520  can be transmitted to the second friction piece  522 . Furthermore, because the ribs  544  of the output member  54  are respectively accommodated within the slots  5223  on another side face of the second friction piece  522  and almost abut against the flanges  5222  ( FIG. 10 ), the movement of the second friction piece  522  can be transmitted to the output member  54 . 
         [0144]    The output member  54  can rotate relative to the base  50 . The oscillation movement of the output member  54  can be transmitted to the second frame  4  via the hanger arm  42  in order to make the second frame  4  and the sitting device secured thereon swing back and forth within a predetermined angular range. 
         [0145]    When the sitting device is swung to a higher position where the sitting device is topmost in the stroke, one of two fingers  519  will be aligned with the sensor  516  and thus the sensor  516  senses the finger  519 . The sensor  516  then sends a signal to a circuit (not shown) installed within the oscillating device  5  so as to control the actuator  510  outputting a smaller torque. This is because the sitting device at the topmost position is going to be swung downwards by its gravity so that a larger torque outputted from the actuator  510  is unnecessary. On the contrary, when the sitting device is swung to a lower position in the stroke, both of the fingers  519  do not aligned with the sensor  516  and thus the sensor  516  does not sense any finger  519 . Thus, the sensor  516  sends another signal to the circuit (not shown) installed within the oscillating device  5  so as to control the actuator  510  outputting a larger torque. This is because the sitting device at the lower position is going to be swung upwards and thus needs external force so that a larger torque outputted from the actuator  510  is necessary. The fingers  519 , sensor  516  and related controlling circuit are helpful to save the electrical power and extend the lifespan of the battery. 
         [0146]    As shown in the  FIGS. 29 ,  30  and  31 , alternatively, the blockers  506  of the base  50  situated at another side of the swing apparatus  2  can stop the movement of the second shaft  53 ′ by abutting the U-shaped first section  531  against either of the blockers  506 . Because the first plane  538  of the second shaft  53 ′ is engaged with the third plane  543  of another output member  54 , the movement of the another output member  54 , together with the second shaft  53 ′, can be restricted by the blockers  506 . Hence, The U-shaped first section  531  and the blockers  506  have the function to avoid the first and second frame  3 ,  4  from being swung over the predetermined range. 
         [0147]    As shown in the  FIGS. 27 and 28 , in another aspect, because the annulus  503  of the base  50  is received within the gripping portion  712  of the gripper  71  and the bulges  504  on the annulus  503  are situated within the notches  716  of the gripper  71 , the gripper  71  clips on the annulus  503  of the base  50  to make the canopy  73  adjustably mounted on the base  50  in a predetermined angle. When the adjustment about the angle of the canopy  73  relative the base  50  is necessary, the users only need to do is to rotate the holders  72 . Because the gripping portions  712  of the grippers  71  are elastically deformable, the bulges  504  on the annulus  503  can overcome the gripping force of the gripping portions  712  to change their relative positions and be received within another set of notches  716 . Therefore, the canopy  73  is situated on the base  50  in another angle. If the canopy  73  is unnecessary, the user can press the bump  725  to release the holder  72  from the gripper  71  and further detach the canopy  73  from the base  50 . 
         [0148]    This invention has been disclosed in terms of specific embodiments. It will be apparent that many modifications can be made to the disclosed structures without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications that are within the breadth and scope of this invention.