Patent Publication Number: US-2023136008-A1

Title: Device for adjusting a blade of a hair trimmer

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a Continuation-in-Part of U.S. patent application Ser. No. 16/789,134 which takes priority from and claims the benefit of U.S. Provisional Patent Application Ser. No. 62/804,827 filed on Feb. 13, 2019, the contents of which are herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to the field of hair trimmers. More specifically, the invention relates to an adjusting device allowing to adjust a clearance between a reciprocating cutter blade and a static comb blade of the blade of a hair trimmer. 
     BACKGROUND OF THE INVENTION 
     Users and barbers use hair trimmers of different sizes and shapes. The hair trimmer has a dynamic cutter blade which slides in a reciprocating movement on top of a static comb blade that is in contact with the skin of a user. In order to prevent cutting through skin, the extremity of the dynamic cutter blade must be adjusted at a very small distance behind that of the static comb blade. This distance, known as clearance, is makes much of a difference on the quality of shaving and is therefore very important to barbers to ensure fine, smooth and safe shaving. 
     Properly adjusting the clearance is not easy however, let alone adjusting it for different models of blades from different manufacturers. Some manufacturers provide an adjuster specific to their blade models, but that nevertheless forces barbers to purchase different adjusters for their different trimmers. There is therefore a need for a trimmer adjuster which can accommodate different blade models. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an adjusting device for adjusting a blade of an electric trimmer that overcomes or mitigates one or more disadvantages of known blade adjusting devices, or at least provides a useful alternative. 
     The invention provides the advantages of being adapted to adjust a variety of blades for electric trimmers from different manufacturers. 
     In accordance with an embodiment of the present invention, there is provided an adjusting device for adjusting a blade of an electric hair trimmer where the blade of the electric trimmer has a dynamic cutter blade and a static comb blade. The adjusting device comprises a base, an adjuster, a locator and a biasing means. The base has a transversal axis, a longitudinal axis and a receiving surface for receiving the comb blade. The adjuster has a comb-contacting face, a cutter-adjusting face and a rotation axis. The adjuster is pivotably connected to the base so that the rotation axis is parallel with the transversal axis of the base. The comb-contacting face is at a first radial distance from the rotation axis while the cutter-adjusting face is at a second radial distance from the rotation axis. The second radial distance is larger than the first radial distance. The locator is connected to the base and is movable along the longitudinal axis of the base. The locator has a receiving portion configured to receive and to locate a non-cutting extremity of the static comb. The biasing means is operable to bias the static comb against the comb-contacting face of the adjuster via the locator. The cutter-adjusting face is operable to displace the cutter blade with respect to the comb blade by pivoting the adjuster around the rotation axis. 
     The receiving surface of the base may be flat. 
     Optionally, the adjusting device may further comprise a locking mechanism operable to selectively prevent the locator from moving with respect to the base. The locking mechanism may be connected to the biasing means and to the base. 
     Optionally, the rotation axis of the adjuster may be substantially co-planar with the receiving surface of the base. 
     Optionally, the cutter-adjusting face of the adjuster may be located above the rotation axis and above the receiving surface of the base. The cutter-adjusting face may have a curved profile in a cross-sectional plane normal to the rotation axis. This curved profile may have increasing second radial distances. 
     Optionally, the receiving portion of the locator may comprise a ramp and a lip. The lip is positioned proximate an upper portion of the ramp so that the non-cutting extremity of the blade is displaced along the ramp up to the lip under a bias of the biasing means. 
     Optionally, the biasing means may be connected between the locator and the base in order to bias the locator substantially along the longitudinal axis of the base. The biasing means may be a spring. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other features of the present invention will become more apparent from the following description in which reference is made to the appended drawings wherein: 
         FIG.  1    is a perspective view from the front of a blade adjusting device in accordance with an embodiment of the invention; 
         FIG.  2    is a perspective view from the back of the blade adjusting device of  FIG.  1   ; 
         FIG.  3    is a sectional view along section  3 - 3  of the blade adjusting view of  FIG.  1    showing a dynamic cutter of a blade adjusted in a first position; 
         FIG.  4    a is a sectional side view along section  3 - 3  of the blade adjusting device of  FIG.  1    showing the dynamic cutter adjusted in a second position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to an adjusting device for adjusting the blades of a hair trimmer that is suited for accepting different models of blades from different manufacturers. 
       FIG.  1    is referred to. An adjusting device  100  for adjusting a blade  102  of an electric trimmer is depicted. The blade  102  of the electric trimmer has a reciprocating cutter blade  104  and a static comb blade  106 . The adjusting device  100  comprises a base  108 , an adjuster  110 , a locator  112  and a biasing means  114 , best shown in  FIGS.  2 ,  3  and  4   , now concurrently referred to. The base  108  has a transversal axis  116 , a longitudinal axis  118  and a receiving surface  120  for receiving the comb blade  106 . The receiving surface  120  of the base  102  is typically flat, or at least provides a flat supporting surface. The adjusting device  100  may be made of plastic or of metal. 
     The adjuster  110  comprises two portions for contacting the blade  102 : a comb-contacting face  122  and a cutter-adjusting face  124 , best shown in  FIG.  2   . A lever  127  is also connected to, or part of, the adjuster  110  to provide leverage so the user can more easily rotate the adjuster  110 . The comb-contacting face  122  serves as a stopper against which the comb blade  106  rests. In certain models of blade  102 , it is also possible that the cutter blade  104  also contacts the comb-contacting face  122  when the comb-contacting face  122  is in a substantially vertical orientation. The comb-contacting face  122  may be flat or curved. If curved, the comb-contacting face  122  adopts a semi-cylindrical surface, at least locally where it is intended to contact the comb blade  106 . This semi-cylindrical shape is of a circular cross-section with a constant radius centered on a rotation axis  126 , the axis around which the adjuster  110  rotates. The rotation axis  126  is typically placed substantially co-planar or in a parallel plane slightly above the receiving surface  120  by a few millimeters (typically between 0 to 2 mm, corresponding to 0 to 0.078 in), and parallel with the transversal axis  116 . The cutter-adjusting face  124  is adapted to contact the cutter blade  104 , above the rotation axis  126  and above the receiving surface  120 . The cutter-adjusting face  124  may adopt a straight or curved profile  146 . Such a curved profile  146  is shown in a plane of the cross-sectional view of  FIG.  3   , which is normal to the rotation axis  126 . Being located above the comb-contacting face  122 , that is closer to the cutter blade  104  itself resting above the comb blade  106 , the cutter-adjusting face  124  is positioned to contact the cutter blade  104  first without contacting the comb blade  106 . Each point along the profile  146  which may potentially contact the cutter blade  104  is located at a gradually increasing radial distance from the rotation axis  126 , thereby allowing gradually pushing the cutter blade  104  along the comb blade  106 . As can be seen, any first radial distance  128 , which is the radial distance of any point along the profile  146  to the rotation axis  126  is larger than any second radial distance  130 , which is the radial distance of any point along the comb-contacting face  122  to the same rotation axis  126 . 
     Adjustment of the cutter blade  104  with respect to the comb blade  106  is achieved by rotating the adjuster  110  around its rotation axis  126 . This is shown in  FIG.  4   . Further rotating the adjuster  110  pushes further the cutter blade  104  with respect to the comb blade  106  and thereby further increase the gap, also known as clearance, between the respective tips of the cutter blade  104  and the comb blade  106 . The exact geometry of the adjuster  110  and of the blade  102  influence how the cutter blade  104  moves with respect to the comb blade  106 . Consequently, the clearance between the cutter blade  104  and the comb blade  106  may not increase proportionally with the rotation angle of the adjuster  110 . 
     Although the cutter-adjusting face  124  is intended to only contact the cutter blade  104  when adjusting, it is possible that the comb-contacting face  122  also marginally displaces the comb blade  106 . The important point is that the cutter-adjusting face  124  displaces more the cutter blade  104  than the comb-contacting face  122  displaces the comb blade  106 . Hence, the objective is to create a relative displacement of the cutter blade  104  with respect to the comb blade  106 . 
     Conveniently, the adjuster  110  is provided with an opening  129  so the user can see through and witness the effect of rotating the adjuster  110  on the position of the cutter blade  104 , and visually assess the clearance. As such clearance is very small, the opening  129  allows the user to use a magnifying glass or a camera of a mobile phone for zooming. 
     The locator  112  is movable along the longitudinal axis  118  of the base  108 , guided by a channel  131 . The locator  112  has a receiving portion  132  configured to receive and to locate a rear portion of the blade  102 , and particularly its non-cutting extremity  134 . Although it depends on the design of a particular blade model, the rear portion of one blade  102  is often constituted of the rear portion, or non-cutting extremity  134 , of the comb blade  106 . The receiving portion  132  of the locator  112  comprises a ramp  136  ending with a retaining lip  138 . The lip  138  is positioned proximate an upper portion of the ramp  136  so that, when positioned, the non-cutting extremity  134  of the blade  102  is guided along the ramp  136  up to the lip  138  under a force exerted by the biasing means  114 . The intersection of the ramp  136  with the lip  138  creates an interior corner  139  designed to hold the non-cutting extremity  134  in place. The location of this corner  139  above the receiving surface  120  determines a height at which rests the non-cutting extremity  134  of the blade  102 . This height is determined so that a bottom  140  of the comb blade  106  rests substantially flat on the receiving surface  120  of the base  108 . It has been found that a distance H between the corner  139  and the receiving surface  120  of approximately 5 mm (0.197 in) suits most brands of blades. If this distance H of 5 mm (0.197 in) does not suit a specific model of blade  102 , it is possible to increase the height of the corner  139  by inserting shims under the locator  112 . Alternatively, it is possible to use thinner or thicker locators  112  to best suit different blade models. 
     The biasing means  114  is typically connected between the locator  112  and the base  108 , and more particularly between the locator  112  and a back wall  142  of the base  108 . So positioning the biasing means  114  allows pushing, or biasing, the locator  112  towards the adjuster  110  substantially along the longitudinal axis  118  of the base  108 . Different types of biasing means  114  may be used, typically a spring which can be a coil spring, a leaf spring, in fact basically any type of suitable spring known in the art made of a metal or plastic. A spring made of a resilient material such as rubber may also be suitable. 
     In order to prevent the locator  112  from being pushed back when rotating the adjuster  110 , the adjusting device may be provided with a locking mechanism  144 . The locking mechanism  144  prevents the locator  112  from moving with respect to the base  108 . The locking mechanism  144  is typically connected between the locator  112  and the base  108 . In the present example, the locking mechanism  144  is a screw passing in a slot  150  of the locator  112  and engaging threads in the base  108 . The screw can be tightened, thereby preventing the locator  112  from moving. 
     A dial  154  may be shown on a face of the base  108  and in proximity to the adjuster  110  to indicate the displacement of the adjuster  110 , which in turn is an indication of the relative displacement of the cutter blade  104  with respect to the comb blade  106 . This dial  154  may be a set of corresponding marks on the adjuster  110  and the base  108  as shown in  FIG.  2   . The corresponding marks may simply be unitless reference marks, may be sequentially-marked marks, may indicate an angular value of the angle of the adjuster  110  with respect to the base  106 , or may indicate the actual displacement value (according to the metric system or to the imperial system) of the cutter blade  104  with respect to the comb blade  106 , for example in tenth of millimeter increments. An alternative way of displaying this information provided by the dial is through the use of a sensor  155  capable of reading or interpreting the movement of the cutter blade  104  and connected to a digital readout  156  as shown in  FIGS.  3  and  4   . The sensor  155  can be a displacement sensor (linear or rotation displacement) or an optical sensor. The sensor may read the movement of the cutter blade  104  directly, that is by being in direct contact or aiming directly at the cutter blade  104  when in place in the adjusting device  100 , or indirectly, that is by monitoring, being in contact or aiming at the adjuster  110  and interpreting the movement of the cutter blade  104  through the movement of the adjuster  110 . 
     In use, the user places the non-cutting extremity  134  of the blade  102  along the ramp  136  of the locator  112  until the non-cutting extremity  134  reaches the corner  139 . While still holding the blade  102 , the user pushes the locator  112  towards a back of the adjusting device  100 , thereby compressing the biasing means  114 . A cutting extremity  152  of the blade  102  is then lowered so that the bottom  140  of the comb blade  106  lays substantially flat against the receiving surface  120  of the base  108 . The biasing means  114  then pushes the blade  102  against the adjuster  110 . If the blade  102  already had a clearance between the cutter blade  104  and the comb blade  106  and if the adjuster  110  is in its raised or starting position such as in  FIG.  3   , only the comb blade  106  should contact the adjuster  110 , and more particularly the comb-contacting face  122 . The locator  112  is then locked into place with the locking mechanism  144 . The cutter blade  104  is loosened from the comb blade  106  so that it can be adjusted. If not already in contact, the cutter blade is brought forward in contact with the cutter-adjusting face  124 . The adjuster  110  is then rotated to an adjusting position as depicted in  FIG.  4   , so that the cutter-adjusting face  124  pushes the cutter blade  104  towards the non-cutting extremity  134  of the blade  102 . This creates the clearance gap between the cutter blade  104  and the comb blade  106 . Once the desired clearance between the cutting extremities of both the comb blade  106  and the cutter blade  104  is achieved, the cutter blade  104  is tightened against the comb blade  106 . The locator  112  is pulled back by loosening the locking mechanism  144 , thereby allowing the removal of the blade  102  from the adjusting device  100 . 
     The present invention has been described with regard to preferred embodiments. The description as much as the drawings were intended to help the understanding of the invention, rather than to limit its scope. It will be apparent to one skilled in the art that various modifications may be made to the invention without departing from the scope of the invention as described herein, and such modifications are intended to be covered by the present description. The invention is defined by the claims that follow.