FR2776847A1 - MANIFOLD BROOM FOR MANIFOLD ELECTRIC MOTORS - Google Patents

Abstract

Collector brush for electrical machines with a commutator, comprising a brush body (13) which can wear out and which is made of electrically conductive material, the brush body (13) on the foot of which is formed a bearing surface (131 ) intended to be placed on a collector (10), and a disconnection member (17) which is driven into the head of the body (13) of the brush, disconnection member (17) which is free, during erosion of the body (13) of the brush until the latter has reached a predetermined residual length and then interrupts the flow of current. The head of the body (13) of the brush is covered by a flat cap (14) which is anchored in the body (13) of the brush and on which the disconnection member (17) bears.

Description

STATE OF THE ART The invention relates to a collector brush for

  collector electric motors, comprising a body of

  broom which can wear out and which is made of an electric material-

  conductive, brush body on the foot of which is formed a bearing surface intended to be placed on a collector, and a disconnecting member which is pressed into the head of the brush body, a disconnecting member which

  is free, during erosion of the broom body, up to

  until it has reached a pre-residual length

  determined and then interrupts the flow of current.

  In the case of an electric hand machine tool, in particular an angle grinder (297 16 245.4), it has already been proposed to extend the switching brushes of the

  electric motor, also known as collection brushes

  tor, in the area of the head of the carbon brush body, by an axial extension which serves as a mount for the connection member and has a dimension such that the spring

  who presses the broom can, to squeeze the coal from the ba-

  lai, dive into the upper outer contour formed between

  the extension of the upper front face and the extensions

  side faces. The disconnecting member is housed in a blind hole made in the extension and the blind hole is closed by compacting coal or a powder.

  metallic. Even the end of the electrical braid is com-

  pact in a lateral recess of the carbon body at a certain distance from the extension. Thanks to this extension, we can achieve that by completely using the space we

  available in the hand-held power tool for mounting

  tage of the carbon brush, the disconnecting member is further away from the foot of the brush body, and that the usable length of the brush body, to the point where it is released from the disconnection member, which is approximately 2 to 3 mm larger than in the case of conventional collector brushes, so that the service life of the electric hand tool is extended by approximately

  30 hours until the next brush change.

  In the case of such a collector brush, it is not possible, for technical reasons, to reduce the dimension

  minimum of the disconnection member in the sliding direction

  the collector brush, below about 7 mm.

  In the case of hand-held electric power tools, the grip circumference is determined in the area of the electric motor

  which is used to guide the machine by hand and must not exceed

  be a maximum dimension, so that we do not have

  poses only of a limited radial mounting dimension for mounting the collector brush including the brush case and the pressing spring. In addition, the life of the broom

  of collector and, consequently, the duration of use of the ma-

  china power tool is a function of the length of the

  tie of the broom body which one has for its wear so that one must inevitably find a compromise

  between the grip periphery and the length of the brush body.

Advantages of the invention

  The collector brush according to the invention is

  characterized in that the head of the broom body is covered by a flat cap which is anchored in the body of the broom and

  on which the disconnecting member rests.

  The collector brush according to the invention thus has the advantage that the cap anchored in the brush body which is made of electrically conductive material and which does not have

  that a low overall height, maintains the de-

  connection in its position. In this way there is no

  volume to reserve for the compaction process in the es

  hollow excavated for the disconnection member, and the part used

  readable from the brush body can be enlarged by height

  saved after compaction. In a real example of realization

  tion the usable length of the broom is thus increased in this way by about 3 mm. Compared with the collector brush described at the beginning, the brush body has a simple geometry of square shape and can be made of a

economically.

  According to an advantageous embodiment of the invention, the cap is made of elastic sheet metal with springs and the anchoring of the cap in the brush body takes place by means of insulating hooks cut in the edge of the cap and folded, which are pressed in recesses in the broom body. The self-locking insulating hooks are simple to carry out in the manufacturing process and prevent the cap from coming loose in

  unassembled sition. When the collector brush is in posi-

  tion mounted the brush spring keeps the cap in addition

in its position.

  According to another characteristic of the invention:

  * the hooks are made in such a way that

  one of the cut edges of the hook extends over the side

  tee of the hook which is turned towards the bottom of the cap parallel to the bottom of the cap,

  * the recesses made in the body of the broom are delimited

  mites, in the direction of the front face of the head of the broom body, respectively by a shoulder which is oriented perpendicular to the axis of the broom body, and

  * the hooks are bent so that the edges are

  hook lugs engage from behind on the

shoulders.

  According to an alternative embodiment of the invention

  the cap is formed in the form of a U-shaped bracket

  tiné to be slipped on the body of brush, cap which comes, by the two branches of the part in U connected by the bottom of the

  cap, engaged with the broom body on two of its sides

  tees located opposite each other, and which is threaded with

  complementarity of form by longitudinal ribs weakened

  projecting inwards on the branches of the U, in longitudinal grooves formed at this point in the

  broom body. The two longitudinal ribs are obtained

  bare in this case preferably by bending the straight ends

  bres branches from 1'U to 90 inwards.

  According to a preferred embodiment of the in-

  vention two legs, located at a certain distance one of

  the other, protrude on at least one edge of the cap, at an-

  straight on the outside of the bottom of the cap which is located opposite the brush body. These tabs serve on the one hand to guide the spring of the broom and to prevent the branch of the spring of the broom which is supported on the cap, from deviating by sliding laterally, and on the other hand to form when the

  broom body has been largely worn, an enlargement of the guide

  dage of the collector broom in the broom case.

  According to an advantageous embodiment of the invention, an electrical cord has been connected by gluing, which is necessary for passing the current towards and from the collector brush to an ear erected on

  the bottom of the cap. In this way we obtain a fabrica-

  simpler because the cord compaction process

  electric in the brush body which, otherwise, is

  if necessary, is deleted. In addition, we must

  take into account a passage of the current rendered a little more

  difficult in some cases of limit tolerances.

  If this is to be avoided, there is a need, according to a

  Another embodiment of the invention, to provide an evi-

  in the bottom of the cap and anchor the electrical cord

  stick in the broom body by passing it through

  this recess. The anchoring takes place, as usual, in com-

  pact the end of the cord in the material of the body

  lai. The electrical cord is anchored in the same head section of the brush body, as that in which

  the disconnection member is inserted and with which the

  puchon comes into engagement. In both cases this takes place

  Let's move the cord connection point

  electric away from the usable section of the body

  lai, so that the useful length of the collection brush

  increased in the electric motor while

  the overall dimension of the broom remains unchanged and that the

  The life of the collector brush is extended.

  According to another characteristic of the invention: * the disconnecting member is incorporated in a blind hole made axially from the head of the brush body in the brush body and has a release member which slides in the blind hole and who is pressed by a

  compression spring resting on the bottom of the cap

  chon and on the release member on the bottom of the bor-

  gne Drawings The present invention will be described below in more detail on the basis of several embodiments shown in the appended drawings in which:

  * Figure 1 shows, in the direction of arrow I in the figure

  gure 2, a front view of a collector broom housed in a broom case

  * Figure 2 shows in the direction of arrow II in the figure

  gure 1, a view of the collector broom with broom case, * Figure 3 shows the same view of the collector broom as that according to Figure 2, but without broom case, * Figure 4 shows a section along line IV -IV of FIG. 3, * FIG. 5 shows a fragment V of FIG. 4 relating to a modified collector brush, * FIG. 6 shows a representation, identical to that of FIG. 5, of a collector brush according to a another example

of achievement.

  Description of the exemplary embodiments

  In FIG. 1, a collector of a collector machine has been designated by the reference 10, preferably a collector motor, on the outer periphery of which is

  radially pressed, by means of a brush spring 21, a ba-

  lai collector 11, brush which is also called a carbon and which is mounted so as to slide axially. The collector brush 11 is housed so as to slide axially in what is called a brush case 12 fixed on a brush holder held in the casing of the machine. In total we have arranged a number of brush cases 12 which corresponds to the number of

  motor excitation poles by distributing them over the

  collector turn offset by the same angle of rotation

one to another.

  The collector brush 11 shown in FIG. 3 in side view, in FIG. 4 in section, and in FIGS. 1 and 2, disposed in the brush case 12, has a brush body 13 made of electrically conductive material, in general of

  coal, at the foot of which is formed a rear support face

  round 131 which corresponds to the outer periphery of the collector and which is used to place it on the collector 10. On the head of the brush body 13, located opposite the foot, a flat, cup-shaped cap 14 has been put in electrically conductive material, cap which, in the embodiment, is made of elastic sheet metal with springs and has a bottom 142 covering the front face of the head of the brush body 13 and

  a cap edge 141 which surrounds the neck-shaped head.

  As can be clearly seen in Figure 4, the cap 14 is anchored by means of hooks 15 in the brush body 13. The hooks 15 are cut on two sides, located in

  look at each other, from the edge of the cap 141 and are

  dark in recesses 16 provided in the brush body 13. In this case, it is advantageous that the edge of the hooks

  151, cut out, which is located opposite the root of the cro-

  chet, either turned towards the bottom of the cap 142 and take ap-

  then on a shoulder 161 in the recess 16, which shoulder

  is oriented perpendicular to the axis of the brush body.

  Thanks to this configuration of the hooks 15, a tensile force which acts on the cap 14 in the direction of traction of the cap 14 from the brush body 13, produced on the

  hooks 15, a force component which is oriented di-

  rection of the bottom of the recess 16, so that the free edge 151 of the hook inclines more strongly towards the bottom of

  the recess 16, and in this way guarantees an absolute fixation

  clearly safe, not detachable from the cap 14 on the body of

  brush 13. The bottom of the recesses 16 can in this case extend

  dre parallel to the side face of the brush body 13 (Figure 4), or at an acute angle with the side face

  of the brush body 13 (FIG. 5). In the example of realization

  tion of the drawings there are provided on each of the two sides which face each other, from the edge of the cap 141, two hooks 15 to

  a certain distance from each other, hooks whose name-

bre can, however, be changed.

  The cap 14 which is put on the head of the brush body 13, serves to fix a disconnection member 17 which is housed in a blind hole 18 made axially in the brush body 13. The disconnection member 17 comprises a

  release member 19, which is roughly in the shape of a cham-

  pinion which is made of electrically non-conductive material

  trice, for example a plastic, and which is inserted in the blind hole so as to slide axially, as well as a compression spring 20 which bears on the one hand on the mushroom head of the release member 19 and on the other hand on the inner face of the bottom 142 of the cap

  14, which presses the mushroom head of the degassing organ

  gement 19 by exerting a prestress on the bottom of the hole

  blind 18. The function of the disconnection member 17 con-

  is to ensure that the electric motor is disconnected

  ché when the collector brush 11 has reached its maximum degree of wear. This is the case when the brush body 13 has been shortened by wear to the point that the bottom of the blind hole 18 is released. In this case the release member 19 is pressed by the compression spring 20 against the surface of the collector 10, and the collector brush 11 is lifted from the collector 10 against the force of the brush spring 21

  (figure 1), so that the circuit of the electric motor

  that is interrupted. To prevent collector 10 from being

  damaged, the depth of the blind hole 18 and the height of the edge 141 of the cap 14 are granted so that the bottom of the blind hole 18 is released, even before the underside of the edge 141 of the cap reaches the manifold 10. The depth of the blind hole 18 must in this way be

  in any case greater than the height of the cap 14.

  As shown in Figures 3 and 4, on at least one side of the square edge 141 of the cap 14, two legs 22, 23 located at a certain distance from each other protrude at right angles on the outer side of the bottom 142 of the cap, located opposite the brush body 13. In the embodiment of Figures 3 and 4 there are provided respectively two tabs of this type 22, 23 on two

  sides opposite one another of the edge 141 of the capu-

  chon and which are the same sides of the edge 141 of the cap in

  which are also cut the hooks 15. The distance between-

  the two legs 22, 23 is in this case fixed in such a way

  lesson that the branch 211 of the brush spring 21 is guided la-

  literally between the legs 22, 23, branch which rests on the outside of the bottom 142 of the cap. The arrangement of the tabs 22, 23 on the sides which are opposite the edge 141 of the cap, means that one can insert into the brush case 12 the collector brush 11 even turned 180 around its longitudinal axis , and that, in doing so, the branch 211 of the brush spring 21 is passed in turn between the legs 22 and 23. As usual, the brush case 12 has a

  side slit, through which engages, on the side

  tee of the spring branch 221 the spring 21 of the brush, which

  consists of a spiral spring and can follow

  vre sliding, due to wear of the collector brush 11

towards collector 10.

  To electrically connect the brush 11 of the collar

  reader there is provided an electric cord 24, the end of which is brought to the cap 14 and which is mechanically fixed at this location. For this, an ear 25 has been formed, on an angle of the cap 14, which projects on the external face of the bottom 142 of the cap at approximately the same height as the tabs 22 and 23. On this ear 25, it is connected by collage

the electrical cord 24.

  In the case of the embodiment, represented

  felt in figure 6, of the collector brush, we did not cons-

  the cap 14 'in the form of a cup but in that of a U-shaped stirrup which engages by its branches 143' and 144 'erected at right angles to the bottom 142' of the cap on the body of broom 13 on its opposite sides,

  and engages there, by longitudi-

  nales 26 which stand up from the U-shaped branches 143 ′, 144 ′ inwards, by shape complementarity, in grooves 27 formed at this location in the body 13 of the brush. As can be seen in FIG. 6, the longitudinal ribs 26 are obtained by bending the free ends of the two U-shaped arms 143 ′ and 144 ′ at right angles inward. The 14 'cap is threaded over the head of the

  body 13 of the broom, passing the longitudinal ribs

  nales in grooves 27 and finally making them

  wedge the cap 14 'by its bottom 142' on the front face-

  tale of the body 13 of the broom. We cannot see the disconnecting device which is also inserted here in the body 13 of the

  broom, in the sectional representation of Figure 6.

  Unlike the collector brush according to Figures 1 to 4, the electric cord 24, in the case of the embodiment of Figure 6, is not fixed by gluing to the cap 14 ', but is anchored in the front face of the body 13 of the brush, the anchoring being carried out in the usual manner by compacting the end of the bead in the material of the body 13 of the brush. The electrical cord 24 is anchored at

  near the side of the body 13 of the broom which is located opposite

  posed on the side where the cap 14 is threaded in the form of a stirrup, so that the disconnection member can be inserted in parallel with the anchoring of the cord in the same front section of the body 13 of the brush. For the purpose of threading the cap 14 'on the body 13 of the brush, provision has been made in the

  bottom 142 'of the cap a recess 28 which ends free-

  ment on the edge of the bottom 142 'of the cap and which is forward in the direction of threading. The width of the recess

  28 is made larger than the diameter of the cor-

  electric gift 24, so that the cap 14 ′ can be threaded without hindrance through the electric cord 24 on the head of the body 13 of the brush, the recess 28 surrounding the

electrical cord 24.

R E V E N DI C A T I ON S

  1) Collector brush for electric collector machines

  reader, comprising a body (13) of brush which can wear out and which is made of an electrically conductive material, body (13) of brush on the foot of which is formed a support surface (131) intended to be placed on a collector (10), and a disconnection member (17) which is pressed into the head of the body (13) of the brush, a disconnection member (17) which

  found free, during an erosion of the body (13) of the broom, up to

  until it has reached a pre-residual length

  determined and then interrupts the flow of current, characterized in that the head of the body (13) of the broom is covered by a flat cap (14) which is anchored in the body (13) of the broom and on

  which is supported by the disconnection member (17).

  2) collector brush according to claim 1, characterized in that

  the cap (14) is made of elastic sheet metal with springs.

  3) Collector brush according to claim 1 or 2, characterized in that the anchoring of the cap (14) takes place in the body (13) of the brush by means of hooks (15) which are cut in the edge

  (141) of the cap and are bent therefrom, cro-

  chets (15) which are driven into recesses (16) practi-

located in the body (13) of the broom.

  4) Collector brush according to claim 3, characterized in that

  * the hooks (15) are constructed so that

  pectively one of the cut edges (151) of the hook extends on the side of the hook which is turned towards the bottom (142) of the cap parallel to the bottom (142) of the cap, * the recesses (16) formed in the body (13) of the brush are delimited, in the direction of the front face of the head of the body (13) of the brush, respectively by a shoulder (161)

  which is oriented perpendicular to the axis of the body of ba

  lai et, * the hooks (15) are bent so that the parallel edges (151) of the hook engage from behind on the shoulders (161). ) Collector mop according to claim 1 or 2, characterized in that * the cap (14) is formed in the shape of a stirrup with a U-shaped profile and engages by branches of the U (143 ', 144 ') which stand at right angles to the bottom (142') of the cap with the body (13) of the brush and,

  * the cap (14) is anchored by means of long ribs

  gitudinal (26) which project inwards from the U-shaped arms (143 ', 144'), longitudinal ribs (26) which are driven into grooves (27) formed in

the body (13) of the brush.

  6) Collector brush according to one of claims 1 to 5,

  characterized in that on at least one side of the edge (141) of the cap (14) protrude two tabs (22, 23) located at a certain distance from each other, at right angles to the outside of the bottom (142) of the cap, which is located opposite the body (13) of the

broom.

  7) collector brush according to claim 6, characterized in that the distance between the two legs (22, 23) has a dimension such that one passes, between the legs (22, 23), a

  spring branch (211) of a brush spring (21) which

  well on the outside of the bottom (142) of the cap for

  fold the brush body (13) onto the collector (10)

  80) Collector brush according to one of claims 1 to 7,

  characterized in that on the cap (14) stands an ear (25) to which is fixed by gluing an electrical cord (24) serving to

pass the current.

  9) Collector brush according to one of claims 1 to 8,

  characterized in that in the bottom (142 ') of the cap (14') is provided a recess (28) through which an electrical cord is passed

  (24) which is anchored in the body (13) of the brush.

  ) Collector brush according to one of claims 1

  9, characterized in that the disconnecting member (17) is incorporated in a blind hole (18) made axially from the head of the body

  (13) of the broom in the body (13) of the broom and has an or-

  release gane (19) which slides in the blind hole (18) and which is pressed by a compression spring (20) taking

  support on the bottom of the cap (142) and on the release member

  housing (19) on the bottom of the blind hole (18).