Abstract:
The invention relates to a hair clipping machine with a device for adjusting the length of a cut, with the adjusting device acting upon the clipping assembly. The clipping assembly includes at least a fixed clipping comb and a clipping blade which can be driven in an oscillatory motion essentially parallel to the front edge of the clipping comb. The adjusting device includes of at least an actuating element which is connected to the clipping blade via coupling elements for displacing the clipping blade lengthwise. The adjusting device is an integral part of the clipping assembly and may therefore be configured independently of the housing. As a result, construction is simplified and it is also possible to retrofit clipping machines which do not have such adjustment devices.

Description:
FIELD OF THE INVENTION 
     The invention relates to a hair clipping machine, in particular to a hair clipping machine adapted to adjust the length of the cut. 
     BACKGROUND OF THE INVENTION 
     Hair clipping machines with a device for adjusting the length of the cut are disclosed in, for example, DE 33 10 706 C2. These hair clipping machines include a cutting assembly consisting of a fixed clipping comb and a clipping blade that can be driven in an oscillatory motion parallel to the front edge, i.e., in a transverse direction. The clipping blade has a fork-shaped catch which engages with an eccentric pin of the drive motor. 
     The underside of the clipping comb has a beveled contour. The length of the cut is adjusted by moving the clipping blade with respect to the front edge of the clipping comb in the longitudinal direction. For this purpose, an actuating element in the form of a slider is provided which is supported in the housing. The actuating element acts on the clipping blade through gear teeth. A displacement of the actuating element therefore causes a displacement of the clipping blade in the longitudinal direction. 
     This mechanism for displacing the clipping blade to adjust the desired length of the cut can be quite complex. In particular, the coupling element, which converts the displacement of the slider, which is supported in the housing, into the desired longitudinal displacement of the clipping blade, has to be carefully constructed. 
     The German patent DE-PS 814 117, which form a basis for the present invention, describes a hair clipping machine, wherein the device for changing the length of the cut is greatly simplified. The device for adjusting the length of the cut includes a carriage which is supported for longitudinal movement relative to the clipping comb and to which the clipping blade is secured. The device also includes an adjustment lever effecting the carriage and positioning the carriage between two end positions. The assembly of the cutting assembly and the device for adjusting the length of the cut, however, requires that all components be connected to the housing of the hair clipping machine, which can become quite complicated. This applies in particular to the support of the adjustment lever on the housing. According to a first embodiment described in the above-referenced patent, the adjustment lever is supported by a bolt of a tightening screw which holds the entire machine together at the center. In other words, all components have to be inserted sequentially and separately, until they can be secured with the tightening screw. According to another embodiment described in the above-referenced patent, the adjustment lever may be supported by an axial bolt which extends completely through the housing. 
     Another type of cutting assembly is disclosed in U.S. Pat. No. 1,774,046 wherein a knurled screw is used to displace the clipping comb relative to a base plate. The base plate is screwed to the housing. A clearance is provided between the clipping comb which is movably supported in the housing, and the housing section located above the comb to receive the clipping blade which can be driven with an oscillatory motion. The support of the clipping blade is very important, since the clipping blade is essentially merely inserted between the clipping comb and the housing and guided by the drive pin of the motor. 
     JP 54-54757 discloses an improved arrangement for guiding a clipping blade with respect to a fixed clipping comb. Supporting blocks are provided in the region of the clipping comb. Each of the supporting blocks receives a respective spring element which is attached to the cutting blade. The spring elements are designed so that the clipping blade can oscillate freely transversely to the clipping comb, while being biased against the clipping comb . With this arrangement, however, the length of the cut cannot be adjusted, since the cutting blade has a fixed axial position with respect to the clipping comb. 
     It is therefore an object of the invention to improve the hair clipping machine of the type described above so as to eliminate the aforedescribed disadvantages. More particularly, it is an object of the invention to simplify the design and thereby also the manufacture of the device for adjusting the length of the cut. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, the complete device for adjusting the length of the cut is fully integrated in the cutting assembly, with the cutting blade supported so as to be able to oscillate freely. Accordingly, the actuating element is also part of the cutting assembly. The entire cutting assembly, which includes the device for adjusting the length of the cut, can now be constructed as a separate assembly which is separate from the housing. This greatly simplifies the design and construction of the device, since no actuating elements for adjusting the lengths of the cut are disposed on the housing. In addition, hair clipping machines which have interchangeable cutting assemblies, may be provided with optional devices for adjusting the length of the cut without changing the design of the hair clipping machines. In addition, existing hair clipping machines that lack a device for adjusting the length of the cut, may be upgraded by a simple change of the cutting assembly without the need for modifying the machine itself. 
     In addition, two support blocks which receive at least one spring element, are also provided on the carriage. The cutting blade is connected to the at least one spring element so that the clipping blade is continuously biased against the clipping comb and supported with a parallelogram-type guide arrangement. 
     Preferably, a support member is provided which receives the carriage. The support member is secured to the clipping comb, preferably in the region of a comb plate which is integrally formed with or attached to the clipping comb. In this way, the carriage is held and guided on the support member and thereby also on the clipping comb and the comb plate, respectively. 
     According to a preferred embodiment of the invention, the actuating element is rotatably supported on the support member and/or on the comb plate. No additional components are required with this type of support. Instead, the actuating element can be supported by pins and corresponding bores in a manner known in the art. With this type of support, the carriage can be controllably displaced simply by rotating or tilting the actuating element. The desired position can thereby be adjusted very precisely and, for example, secured with conventional locking devices known in the art. 
     The rotation and tilting motion of the actuating element can be readily transformed into the desired translation or displacement motion of the carriage with the help of a retaining pin which engages and cooperates with a corresponding slotted groove. The retaining pin can be attached, for example, to the actuating element and cooperate with the slotted groove disposed on the carriage. Alternatively, it would also be possible to attach the retaining pin to the carriage and the slotted groove on the actuating element. 
     Alternatively, a gear wheel can also be attached to the actuating element, wherein the gear wheel cooperates with at least one corresponding rack segment disposed on the carriage. 
     To transmit the force more evenly, two gear wheels are advantageously arranged symmetrically with respect to the longitudinal axis, rotating in opposite directions. The gear wheels cooperate with two corresponding rack segments disposed symmetrically with respect to the longitudinal axis on the carriage. The force is then applied exactly symmetrically with respect to the longitudinal axis of the carriage. This eliminates jamming which may occur if the force is applied predominantly from one side. 
     The cutting assembly of the invention which includes the device for adjusting the length of the cut, may also be designed so that either the clipping comb and/or the support member are attached to the housing, with the clipping blade being moved to adjust the length of the cut. Alternatively, the carriage may be affixed to the housing, and the length of the cut is adjusted by adjusting the position of the clipping comb. 
     The clipping comb may also be displaced by providing an additional holder which is connected with the support member, with the clipping comb supported in the holder for displacement in the longitudinal direction. 
     Other preferred embodiments of the invention reduce the complexity of assembling the cutting assembly, including the device for adjusting the length of the cut. For example, the support member and the holder, and possibly also the comb plate and the holder may be formed from a thermoplastic material and heat-fused after the individual components, in particular the carriage and the actuating element, have been fitted together. This type of assembly technique obviates the use of screws. 
     The invention will be described hereinafter with reference to the embodiment illustrated in the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal cross-section of a basic design of a hair clipping machine; 
     FIG. 2 a  is a longitudinal section of a cutting assembly, with a pin guided in a slotted groove; 
     FIG. 2 b  is a top view of the cutting assembly according to FIG. 2 a;    
     FIG. 2 c  is the cutting assembly according to FIG. 2 b  with the clipping blade in a different position; 
     FIG. 3 a  is a longitudinal section of the cutting assembly with an adjustment wheel for symmetric force transmission; 
     FIG. 3 b  is a top view of the cutting assembly of FIG. 3 a;    
     FIG. 4 a  is a longitudinal section of the cutting assembly with an eccentric lever and a displacement slider; 
     FIG. 4 b  is a top view of the cutting assembly according to FIG. 4 a;    
     FIG. 5 is a top view of the cutting assembly with a pivoting lever, with the gear wheel acting on one side; 
     FIG. 6 is a top view of the cutting assembly with an eccentric lever, with the pin acting in the center; 
     FIG. 7 is a longitudinal section of the cutting assembly, with the carriage secured to the housing; and 
     FIG. 8 is a longitudinal section of the cutting assembly, with the clipping comb pulled out. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following detailed description of the figures, corresponding elements have the same reference numbers. Only the differences between the various embodiments and the basic design will be described. 
     Referring now to FIG. 1, the basic design of a hair clipping machine with a device for adjusting the length of the cut includes a drive motor  4  which is inserted in a housing  1 . The drive motor  4  drives a clipping blade  20  in an oscillatory motion in the transverse direction, i.e., in a plane which is perpendicular to the plane of the longitudinal section. The clipping blade  20  faces a clipping comb  10 , with the clipping blade  20  and the clipping comb  10  forming a clipping assembly  8 . The clipping assembly  8  is releasably connected to the housing  2  for interchangeablility, which is known in the art. 
     According to one feature of the invention, integrated into the clipping assembly  8  is a device for adjusting the length of the cut. The clipping blade  20  can be displaced in the longitudinal direction to adjust the desired length of the cut. The device for adjusting the length of the cut consists essentially of an actuating element  40  acting on a carriage  30 . The carriage  30  is connected to the clipping blade  20 , so that the displacement motion of the carriage  20  is directly transmitted to the clipping blade  20 . 
     As seen from FIG. 1, it is not necessary to provide additional components on the housing for displacing the clipping blade  20  relative to the clipping comb  30  in the longitudinal direction. In other words, the desired length of the cut is adjusted with the help of components which are integrated in the clipping assembly  8 . The clipping assembly  8  can therefore be advantageously made interchangeable with existing cutting assemblies which lack adjustability. Consequently, existing hair clipping devices can be easily upgraded. 
     Various modifications for implementing the device for adjusting the length of the cut will now be described with reference to the remaining figures. The following embodiments are intended to show the various arrangements of actuating elements  40  and coupling elements which can be used to adapt the displacement motion of the carriage  30 . 
     FIGS. 2 a - 2   c  show an enlarged view of the clipping assembly  8  of FIG.  1 . The design of the actuating element  40  is also different. A comb plate  12  which supports the entire device for adjusting the length of the cut, forms one piece with the clipping comb  10 . The clipping blade  20  is disposed in the front region and can be driven by the cam  6  (not shown) via a catch  21 . 
     The actuating element  40  is formed as a pivoting lever and guided between the comb plate  12  and a support member  50 . The actuating element  40  includes a pin  41  which engages with a corresponding groove  32  formed on the carriage  30 . The carriage  30  can be engaged and moved in the direction of the front edge of the clipping comb  10  by pivoting the actuating element  40  about a pivot axis  49 , until the position illustrated in FIG. 2C is reached. The maximum length of the displacement B is defined by the length of the slotted groove  32  in conjunction with the arrangement of the pin  41  relative to the actuating element  40 . 
     The carriage  30  includes additional guide pins  36  which engage in guide grooves  56  of the support member  50 . This arrangement assures that the carriage  30  is displaced exactly in the longitudinal direction, even if—as in the present example—the force effecting the displacement of the carriage is applied off-center. 
     According to a particular embodiment of the carriage, two support blocks  31  for supporting a spring element  60  are symmetrically formed on the carriage  30 . The spring element  60  is formed as one piece and includes two spaced apart, mutually parallel spring legs  62  and two spring coils  64  which are used to insert the spring element  60  into the support blocks  31 . The end portions of the spring legs  62  make contact with the clipping blade  20 , thereby providing a connection with the carriage  30 . The spring coils  64  produce a biasing force which continually urges the clipping blade  20  against the clipping comb  10 . In addition, the arrangement of the spring arms  62  represents a parallelogram guide which enables the oscillatory displacement motion transversely to the longitudinal axis. 
     In the embodiment of the invention illustrated in FIGS. 3A and 3B, the actuating element  40  is an adjustment wheel which drives two meshing gear wheels  43 . Each of the gear wheels  43  engages with a rack segment  33  attached to the carriage  30 . A rotating motion of the adjustment wheel is thereby converted into a linear displacement motion of the carriage  30 . With this type of coupling between the actuating element  40  and the carriage  30 , the force applied to the carriage  30  is completely symmetric with respect to the longitudinal axis, i.e., in a direction parallel to the displacement direction. The actuating forces can thus be kept small, since the carriage  30  can no longer become wedged in the groove  56 . 
     According to the embodiment illustrated in FIGS. 4A and B, the actuating element  40  is an eccentric lever which is supported off-center between the comb plate  12  and the support member  50  for rotation above the pivot axis  39 . One end of the eccentric lever includes a pin  41  which engages the carriage  30  in the region of a shoulder disposed on the slider  34 . 
     The actuating element  40  in this embodiment can be arranged slightly to the side of the clipping assembly  8 . The device for adjusting the length of the cut has the additional ergonometric advantage that it can be operated with the thumb when the hair clipping machine is in use. 
     The design of the embodiment shown in FIG. 5 is particularly simple. The actuating element  40  is a pivoting lever supporting a single gear wheel  43 . The gear wheel  43  is aligned with a rack segment  33  of the carriage  30 . The carriage  30  can be displaced linearly by rotating the pivoting lever. 
     The arrangement illustrated in FIG. 5 has the added advantage that the line of engagement of the rack segment  33  coincides with the symmetry axis of the clipping assembly  8 . The pivot axis  49  of the pivoting lever is here disposed slightly off-center, so that the force can be applied symmetrically to prevent the carriage  30  from becoming wedged. 
     Referring now to the embodiment of FIG. 6, an actuating element  40  has the form of an eccentric lever which is also supported off-center for rotation about the pivot axis  49 . A pin  41  which engages a groove  32  disposed on the carriage  30 , is disposed on the eccentric lever. 
     Unlike the embodiment of FIGS. 4A and 4B, the pivot axis  49  is here positioned as far away from the symmetry axis as possible, which, allows the attack point of the force on the carriage  30  with respect to the symmetry axis to be maintained at an essentially fixed position. When the carriage is moved between the two end points, the attack point of the pin  41  moves only a very small distance relative to the carriage  30 . This small movement is further compensated by the guide grooves  56 . 
     The carriage  30  of the embodiment shown in FIG. 7 can be secured to a housing  2  (not shown). For this purpose, the carriage  30  includes support ribs which engage with corresponding grooves disposed on the housing  2 . Actuation of the actuating element  40  then causes the comb plate  12  together with the clipping comb  10  to be displaced in the longitudinal direction. 
     Referring now to the embodiment illustrated in FIG. 8, the length of the cut can be adjusted by displacing the clipping comb  10 . A holder  70  is connected to the support member  50 , wherein the clipping comb  10  is guided in the holder for longitudinal displacement. The actuating element  40  acts directly on the clipping comb  10  and displaces the clipping comb  10  relative to the clipping blade  20 . 
     The aforedescribed arrangement is easier to manufacture, since the support member  50  can be fused with the holder  70 , if both components are made of a thermoplastic plastic. In this way, conventional fasteners, such as screws or rivets, may be completely eliminated.