Title of Invention	SEWING MACHINE WITH OIL TANK AND OIL TANK IMMERSION BODY OF THE SEWING MACHINE
Abstract	An oil-deficiency indicator for sewing machines which comprise an oil tank (16) for supply of at least one lubricating point is characterized by an immersion body (60) which is insertable from above into the oil tank (16) and has a bottora of transparent material; at least one reflection surface (84, 86) on the transparent bottom; a light source (78) above the reflection surface which emits a light beam on to the reflection surface (84, 86); and a light receiver (80) in the beam path of the light beam of the light source (78) which is reflected by the reflection surface, releasing a switching pulse by reception of light.

Title of Invention

SEWING MACHINE WITH OIL TANK AND OIL TANK IMMERSION BODY OF THE SEWING MACHINE

Abstract

An oil-deficiency indicator for sewing machines which comprise an oil tank (16) for supply of at least one lubricating point is characterized by an immersion body (60) which is insertable from above into the oil tank (16) and has a bottora of transparent material; at least one reflection surface (84, 86) on the transparent bottom; a light source (78) above the reflection surface which emits a light beam on to the reflection surface (84, 86); and a light receiver (80) in the beam path of the light beam of the light source (78) which is reflected by the reflection surface, releasing a switching pulse by reception of light.

Full Text	Sewing Machine with Oil Tank and Oil Tank Immersion Body of the Sewing Machine The invention relates to a sewing machine with an oil tank according to the preamble of claim 1. The invention further relates to an oil tank immersion body of a sewing machine according to claim 14. Sewing machines comprise a number of bearings which must be provided with lubricant, in particular oil. To this end, sewing machines have at least one oil tank which is connected to lubricating points by conduits, The con- duits used most y are wick conduits i.e., wicks inserted in a hose, conduits of that type enabling the oil to flow slowly and continuously and to be transported not only downwards but even upwards to a restricted extent. Of course, oil must always be sufficiently available in the oil tank. However, monitoring the level of the oil tank is rather complicated, the oil tank being regularly integrated inside the housing of the sewing machine. Conse- quently it is necessary from time to time to open the housing or corre- sponding parts of the housing and to check the level. US 2 301 460 A teaches, in the case of oil-tanks located above the base plate in the stan iard or in the arm, to provide the machine housing with an inspection glass that will enable the level of oil to be checked without dis- assembly of the housing. However, discerning the level of an oil tank through an inspection glass poses some problems so that a lack of oil fre- quently remains unnoticed for some time. With sewing machines in a sewing workshop not always consuming the same quantities of oil, checking the level must take place as early as possi- ble for reasons of safety. Therefore avoiding a lack of oil in a machine and any possible damages that might result is accompanied with quite a few technical requirements. Oil-level indicators for sewing machines are also known from DE 29 37 772 B1 and DE 29 23 750 A1. It is an object of the present invention to improve a sewing machine of the type mentioned at the outset in such a way that an oil-level monitoring sys- tem of simple design is obtained that works reliably and can possibly be retrofitted. According to the invention, this object is attained in a sewing machine comprising the features mentioned in the characterizing part of claim 1. The invention proceeds from the idea that a light beam that hits the reflec- tion surface of the immersion body passes through the reflection surface into the oil as long as the reflection surface is wetted by oil, but that it will be reflected one e the level has lowered to such an extent that oil no longer rinses the reflection surface. Then the light beam will be reflected by the reflection surface and can be absorbed by a light receiver, for example a photo-active diode, thus triggering a switching pulse for an optical or acoustic alert signal. The material of the immersion body is transparent when it is permeable to light of a given wavelength, namely the wavelength of the light beam emitted by the source of light. The immersion body may for instance be a hollow body having a bottom of transparent material, or it may be a structure entirely of transparent material in which the outer sur- faces constitute the reflection surfaces. Preferably the immersion body is inserted vertieally from above into the oil tank, and the reflection surface is located in the bottom portion of the sub- stantially bar-shaped immersion body, A reflection surface of a design in the form of a plane surface of a transpar- ent bottom of the immersion body is easy to manufacture, simultaneously offering sufficient reflection properties. The light source and the light receiver are disposed preferably close to each other in the top area of the immersion body so that they may be arranged on a joint plate with joint electric connection. In as much as, in this context and in particular in connection with the preferred embodiment explained below, the immersion body is mentioned to be inserted from above into the oil tank and the light source as well as the light receiver to be located in the top area of the immersion body, it is stressed once again that the direction of insertion of the immersion into the oil tank is not of substantial impor- tance for the effect of the invention. The term "top" is used for simplifica- tion of wording. The immersion body may just as well enter laterally or from below into the oil tank, in which case the light source and the light receiver are preferably located in the most remote or the lowennost posi- tion of the immersion body. Recesses for the light source and the light receiver in the top area of the immersion body constitute an advantageously compact design for oil-level monitoring. The reflection surface is in particular an outer surface of the immersion body, having the mentioned sectionally reflecting properties, namely of allowing the light beam to enter into the oil as long as the immersion body is immersed in oil, but, upon lack of oil, having a reflecting effect. What is meant is at least a change in the reflection properties in oil on the one hand and in air on the other. Such a reflection behaviour can for instance be ob- tained by a prismatic immersion body of glass or synthetic resin. Provision may also be made for two reflection surfaces, for example two surfaces of opposite inclination, in particular opposed by 45°, the first of which reflecting the beam towards the second and the second reflecting the beam in paralle back again, In this way, the light source, for instance a light emitting d ode, and the light receiver, for example likewise a photo- active switching diode, can be disposed side by side in the top area of the immersion body in corresponding recesses. The light source and the light receiver may be disposed on a common bear- ing plate which is mounted on, for example interlocked with, the top end of the immersion body in such a way that the two diodes enter into the re- cesses of the immersion body. The immersion body, together with the light source and the light receiver as an integral unit, may be integrated in a top cover of the oil tank. The light receiver preferably controls an indicator lamp which is visible from outside, blinking when light reaches the light receiver, meaning that the oil level has sunk to such a degree that the reflection surface or reflec- tion surfaces are bare. The indicator lamp may as well be integrated in the immersion body, being mounted in particular on the bearing plate thereof and accommodated in a corresponding recess of the immersion body. Allo- cated to the md.cator lamp may be a reflection surface by which the light of the indicator lamp is deflected into a position that is visible from out- side. Diodes are especially suitable for the job of the light source, light receiver and the indicator lamp. These components are available at a low cost. The wavelength of the light source and the indicator lamp and, respectively, the sensitivity of the light receiver can be selected from a plurality of standard diodes for complying with the requirements of a sewing machine according to the invention in particular in terms of the immersion-body material which the emitted light will pass through. A design of the immersion body according to claim 13 is especially com- pact. In a sewing machine according to the invention, the oil tank is comprised in a vertical standard of a housing where it is located behind a window through which to see the alert signal from outside. Any lack of oil is easily visible from outside when the indicator lamp blinks. There is no need of any precautionary check, in close series, of the level of oil. Another object of the invention resides in specifying an immersion body for the oil tank of a sewing machine by which to create an oil-level moni- toring unit for retrofitting. According to the invention, this object is attained by an immersion body according to claim 14. The immersion body according to the invention is suitable for retrofitting even the oil tanks of existing sewing machines easily and at a low cost. The advantages of the immersion body correspond to those discussed above in connection with the sewing machine according to the invention. Details of the invention will become apparent from the description of pre- ferred embodiments, taken in conjunction with the drawing, in which Fig. 1 is an overall illustration of a sewing machine according to the in- vention , comprising an oil tank with an oil-deficiency display ac- cording to the invention; Fig. 2 is an enlarged side view, partially broken away, of the oil tank ac- cording to the invention; Fig. 3 is a plan view of the oil tank of Fig. 2; Fig. 4 is a perspective view of a cover of the oil tank according to Figs. 2 and 3; Fig. 5 is a sectional view of the cover of Fig. 4 on the line V-V of Fig. 3; Fig. 6 is a sectional view, on the line VI-VI of Fig. 3, of details of the cover of the oil tank comprising an immersion body; Fig. 7 is a view of the oil tank from the right in Fig. 2. Fig. 1 is a diagrammatic side view of a sewing machine, comprising a base plate 10 in the form of a casing, a standard 12 standing out vertically there- from, and a horizontal arm 14 that proceeds from the top end of the stan- dard 12 in parallel to the base plate 10. A driven arm shaft (not seen in Fig. 1) is conventionally supported in the arm 14;, a diagrammatically outlined needle bar 15 with a needle is drivable by the arm shaft in up and down reciprocation. Disposed in the standard 12 is a first oil tank 16 which will be referred to in detail below in the description. A second oil tank 18 is disposed in the cas- ing 10. The first oil tank 16 feeds an area of needle guidance (not shown) by way of a wick conduit 20 and a distributor 22 as well as a second wick conduit 24. By way of another wick conduit 26, the first oil tank 16 supplies the second oil tank 18 with oil, the second oil tank 18 being again connected to a shut- tle 30 via another wick conduit 28. A bottom area of the base plate 10 ac- commodates an oilpan 32 that serves for collecting any dripping oil. This oil is pumped, back to the distributor 22 via a conduit 34 where a pump 36 is located that is driven by a motor 38. Further details of the overall sewing machine are of the importance in this context. The following i s a detailed description of the oil tank 16, taken in conjunc- tion with Figs. to 7. According to Figs. 2 and 3, the oil tank 16 has a box frame 40, some details of the shape of which being adapted to the locally available space as seen in Fig. 3. The oil tank 16 is fitted into a recess 42 of a casing wall 44 of the standard 12 of the sewing machine. The box frame 40 is closed by a cover 46 that is seen in particular in Figs. 2 and 4. The cover 46 comprises a raised area 48 of stepped ascent and a lower area 50 substantially in the form of a plate. This plate-type area 50 has two holes 52, 54 passing into tubes 56, 58 on a bottom side of the plate-type area 50. These tubes accommodate the wick conduits 20,26 which have been men- tioned in connection, with Fig. 1 and are shown in Figs. 2 and 7, but not in the other illustrations. Between the two tubes 56, 58, an immersion body 60 is fixed to the bottom side of the plate-type area 50 of the cover 46, in particular integrally molded on the cover 46 as a one-piece plastic piece. The immersion body 60 projects into a supplies reservoir 61 of the oil tank 16. Three holes 62, 64,66 of triangular arrangement are located in the plate-type area 50; they are allocated to the immersion body 60, passing into corresponding re- cesses 68, 70,72 in the top area of the immersion body 60. Two recesses 68, 70 which align with the holes 62, 64 are illustrated in Fig. 6. The third recess 72 which aligns with the third hole 66 is seen in Fig. 5. Apart from these recesses 68, 70, 72, the immersion body 60 is a solid structure of transparent material, for instance' acrylic glass. A bearing plate 74 is placed on the cover 46 in the vicinity of the immer- sion body 60; it is in particular locked into place by the aid of a detent 76 that is integrally molded on the cover 46. Disposed on the bearing plate 74, in positions allocated to the three recesses 68, 70, 72, are a light emitting diode 78 as a light source, a photodiode 80 as a light receiving, diode, and another light emitting diode 82. The photodiode 80 and the additional, light emitting diode 112 are connected for signalling. The additional light emit- ting diode 82 serves as an indicator lamp to be switched on and off by the photodiode 80. Figs. 5 and 6 are two sectional views, perpendicular to one another, of the immersion body 60, seen on the lines V-V and VI-VI of Fig 3 The sec- tional view of Fig, 6 shows the light emitting diode 78 and the photodiode 80. The sectional view of Fig. 5 shows the indicator lamp 82. A bottom of the immersion body 60 comprises two slopes which incline towards each other by approximately 45° and are designated as surfaces of reflection 84, 8(i. A light beam 88 emitted by the light emitting diode 78 hits the first reflection surface 84. As long as the immersion body 60 is immersed in the oil bath inside the oil tank 16, the beam runs substantially straight through the reflection surface 84 into the oil bath as outlined by a dot-dashed line. When the oil bath has dropped to such an extent that the bottom of the im- mersion body 6) lies bare, the light beam 88 is deflected by the two reflec- tion surfaces 84, 86 in such a way that it is reflected in parallel towards the photodiode 80. The photodiode 80 emits a switching pulse, switching on the indicator larap 82 so that it emits a light signal. As mentioned, the wall 90 (on the right in Figs. 2 and 3) of the box frame 40 is embedded in the recess 42 of the casing wall 44 of the sewing ma- chine. The result is a window 92 (Fig. 1) through which the oil tank 16 be- comes visible from outside. With the recess 42 not dimensioned for the indicator lamp 82 to be visible directly from outside, the light beam of the indicator lamp K2 is led through an attachment 94 of the immersion body 60 and on to a reflection surface 96, disposed by 45°, of the attachment, from where it is reflected by 90° out of the immersion body 60 and out- wards through the window 92. This means that the signal of the light emit- ting diode 78 is visible from far at a characteristic place on the outside of the sewing machine, drawing the staffs attention to the lack of oil. It must be added that Figs.-2,4,5 and 6 show a line 98, also seen in Fig. 1, which produces a connection between the diodes 78 to 82 and supply elec- tronics 100. The invention creates a compact oil-level monitoring unit which can be used for example as a substitute in connection with a conventional oil tank. The cover 46 ard the immersion body 60 can be injection-molded as an integral unit. Electric connections need to be provided only as far as to the bearing plate 74 on the top side of the immersion body 60. No movable parts are in the oil bath, nor are there any electric or electronic lines. As mentioned, the spatial orientation, namely the insertion of the immer- sion body 60 from above, laterally or from below, is of no importance per se. It is decisive that the immersion body 60 comprises a surface which is temporarily immersed in oil when the oil tank 16 is full and which lies bare as the oil tank 16 empties. In any case it is advantageous that the cover 46 of the oil tank 16 or any corresponding c overing member be injection-molded integrally with the immersion body 60. The shape of the immersion body 60 is of no importance either. Solely a reflection surface is indispensable, to which to emit a light beam from the light source i.e. from the light emitting diode 78. This can be put into prac- tice directly or by deflection via additional reflection surfaces. Of course, the second oil tank 18 which is disposed in the base plate 10 of the machine can be provided with an oil-deficiency indicator or oil-level monitoring unit according to the invention, in the same way as the oil tank 16 of the embodiment described. However, level monitoring, according to the invention, of the top oil tank 16 is especially advantageous, provided the oil tank 16 is connected to the bottom oil tank 18 in the way of the em- bodiment described. The bottom oil tank 18 is connected to the top tank via the conduit 26, md a check valve (not referenced) prevents the bottom oil tank 18 from running over. This means that the bottom oil tank 18 will al- ways be filled appropriately as long as there is any substantial quantity of oil in the top oil tank 16. In other words, monitoring the top oil tank 16 by an indicator system ac- cording to the invention provides for the fact that both oil tanks 16,18 are always filled adequately. Claims 1. A sewing machine, comprising an oil tank (16) for supply of at least one lubricating point; characterized by an immersion body (60) which is at least sectionally made of transpar- ent material, projecting into a supplies reservoir (61) of the oil tank (16) and having at least one reflection surface (84,86) accessible from the supplies reservoir;- a light source (78) for emitting a light beam (88) on to the reflection surface (84, 86); a light receiver (80) which is disposed in the beam path of the light beam of the light source (78) that is reflected by the reflection, surface (84, 86), the light receiver (80) being designed for triggering a switch- ing pulse when the light beam (88) hits the light receiver (80). 2. A sewing machine according to claim 1, characterized in that the im- mersion body (60) projects from above into the oil tank (16) and in that the light source (781 and the light receiver (80) are located in a top area of the immersion body (60). 3. A sewing machine according to claim 1 or 2, characterized: in that the reflection surface (84, 86) is a plane surface of a transparent bottom area of the immersion tody (60). 4. A sewing machine according to claim 2 or 3, characterized in that the light source (781 and the light receiver (80) are disposed side by side in the top area of the immersion body (60). 5. A sewing machine according to one of the preceding claims, character- ized in that recssses (68, 70,72) for the light source (78) and the light re- ceiver (80) are provided in the top area of the immersion body (60), the overall immersion body (60) preferably consisting of transparent material. 6. A sewing machine according to one of the preceding claims, character- ized in that the reflection surface (84, 86) is formed by an outer surface of the immersion 1 ody (60). 7. A sewing machine according to one of the preceding claims, character- ized in that two reflection surfaces (84, 86) are provided, which incline such that the light beam that is reflected by the reflection surfaces (84, 86) is reflected by the reflection surfaces (84, 86) in parallel to the beam of the light source (781 back towards the light receiver (80). 8. A sewing machine according to one of the preceding claims, character- ized in that the light source (78) and the light receiver (80) are disposed on a bearing plate (74) which is placed on, in particular snap-engaged with, the immersion body (60). 9. A sewing machine according to one of the preceding claims, character- ized in that an indicator lamp (82) is provided, which is visible from out- side and able to be switched by the light receiver (80) 10. A sewing machine according to claim 9, characterized in that the in- dicator lamp (82) is integrated into the top area of the immersion body (60). 11. A sewing machine according to claim 10, characterized in that the indicator lamp (82) is located in a recess (72) in the top area of the immer- sion body and in that the indicator lamp (82) is also mounted on the bear- ing plate (74). 12. A sewing midline according to one of the preceding claims, charac- terized in that the light source (78), the light receiver (80) and the indica- tor lamp (82) are diodes. 13. A sewing machine according to one of the preceding claims, charac- terized in that the immersion body (60) is an integral component of a cover (46) of the oil tank (16) and in that the bearing plate (74) is fixed to the cover (46), with the light source (78), the light receiver (80) and the indicator lamp (32) projecting into recesses (68, 70, 72) of the immersion body through corresponding holes (62, 64, 66) of the cover (46). 14. An immersion body (60) for use in a sewing machine according to one of claims 1 to 13. Abstract An oil-deficiency indicator for sewing machines which comprise an oil tank (16) for supply of at least one lubricating point is characterized by an immersion body (60) which is insertable from above into the oil tank (16) and has a bottora of transparent material; at least one reflection surface (84, 86) on the transparent bottom; a light source (78) above the reflection surface which emits a light beam on to the reflection surface (84, 86); and a light receiver (80) in the beam path of the light beam of the light source (78) which is reflected by the reflection surface, releasing a switching pulse by reception of light.

Full Text

Sewing Machine with Oil Tank and Oil Tank Immersion Body of the
Sewing Machine
The invention relates to a sewing machine with an oil tank according to the
preamble of claim 1. The invention further relates to an oil tank immersion
body of a sewing machine according to claim 14.
Sewing machines comprise a number of bearings which must be provided
with lubricant, in particular oil. To this end, sewing machines have at least
one oil tank which is connected to lubricating points by conduits, The con-
duits used most y are wick conduits i.e., wicks inserted in a hose, conduits
of that type enabling the oil to flow slowly and continuously and to be
transported not only downwards but even upwards to a restricted extent. Of
course, oil must always be sufficiently available in the oil tank. However,
monitoring the level of the oil tank is rather complicated, the oil tank being
regularly integrated inside the housing of the sewing machine. Conse-
quently it is necessary from time to time to open the housing or corre-
sponding parts of the housing and to check the level.
US 2 301 460 A teaches, in the case of oil-tanks located above the base
plate in the stan iard or in the arm, to provide the machine housing with an
inspection glass that will enable the level of oil to be checked without dis-
assembly of the housing. However, discerning the level of an oil tank
through an inspection glass poses some problems so that a lack of oil fre-
quently remains unnoticed for some time.
With sewing machines in a sewing workshop not always consuming the
same quantities of oil, checking the level must take place as early as possi-
ble for reasons of safety. Therefore avoiding a lack of oil in a machine and

any possible damages that might result is accompanied with quite a few
technical requirements.
Oil-level indicators for sewing machines are also known from DE
29 37 772 B1 and DE 29 23 750 A1.
It is an object of the present invention to improve a sewing machine of the
type mentioned at the outset in such a way that an oil-level monitoring sys-
tem of simple design is obtained that works reliably and can possibly be
retrofitted.
According to the invention, this object is attained in a sewing machine
comprising the features mentioned in the characterizing part of claim 1.
The invention proceeds from the idea that a light beam that hits the reflec-
tion surface of the immersion body passes through the reflection surface
into the oil as long as the reflection surface is wetted by oil, but that it will
be reflected one e the level has lowered to such an extent that oil no longer
rinses the reflection surface. Then the light beam will be reflected by the
reflection surface and can be absorbed by a light receiver, for example a
photo-active diode, thus triggering a switching pulse for an optical or
acoustic alert signal. The material of the immersion body is transparent
when it is permeable to light of a given wavelength, namely the wavelength
of the light beam emitted by the source of light. The immersion body may
for instance be a hollow body having a bottom of transparent material, or it
may be a structure entirely of transparent material in which the outer sur-
faces constitute the reflection surfaces.

Preferably the immersion body is inserted vertieally from above into the oil
tank, and the reflection surface is located in the bottom portion of the sub-
stantially bar-shaped immersion body,
A reflection surface of a design in the form of a plane surface of a transpar-
ent bottom of the immersion body is easy to manufacture, simultaneously
offering sufficient reflection properties.
The light source and the light receiver are disposed preferably close to each
other in the top area of the immersion body so that they may be arranged
on a joint plate with joint electric connection. In as much as, in this context
and in particular in connection with the preferred embodiment explained
below, the immersion body is mentioned to be inserted from above into the
oil tank and the light source as well as the light receiver to be located in the
top area of the immersion body, it is stressed once again that the direction
of insertion of the immersion into the oil tank is not of substantial impor-
tance for the effect of the invention. The term "top" is used for simplifica-
tion of wording. The immersion body may just as well enter laterally or
from below into the oil tank, in which case the light source and the light
receiver are preferably located in the most remote or the lowennost posi-
tion of the immersion body.
Recesses for the light source and the light receiver in the top area of the
immersion body constitute an advantageously compact design for oil-level
monitoring.
The reflection surface is in particular an outer surface of the immersion
body, having the mentioned sectionally reflecting properties, namely of
allowing the light beam to enter into the oil as long as the immersion body

is immersed in oil, but, upon lack of oil, having a reflecting effect. What is
meant is at least a change in the reflection properties in oil on the one hand
and in air on the other. Such a reflection behaviour can for instance be ob-
tained by a prismatic immersion body of glass or synthetic resin.
Provision may also be made for two reflection surfaces, for example two
surfaces of opposite inclination, in particular opposed by 45°, the first of
which reflecting the beam towards the second and the second reflecting the
beam in paralle back again, In this way, the light source, for instance a
light emitting d ode, and the light receiver, for example likewise a photo-
active switching diode, can be disposed side by side in the top area of the
immersion body in corresponding recesses.
The light source and the light receiver may be disposed on a common bear-
ing plate which is mounted on, for example interlocked with, the top end of
the immersion body in such a way that the two diodes enter into the re-
cesses of the immersion body. The immersion body, together with the light
source and the light receiver as an integral unit, may be integrated in a top
cover of the oil tank.
The light receiver preferably controls an indicator lamp which is visible
from outside, blinking when light reaches the light receiver, meaning that
the oil level has sunk to such a degree that the reflection surface or reflec-
tion surfaces are bare. The indicator lamp may as well be integrated in the
immersion body, being mounted in particular on the bearing plate thereof
and accommodated in a corresponding recess of the immersion body. Allo-
cated to the md.cator lamp may be a reflection surface by which the light
of the indicator lamp is deflected into a position that is visible from out-
side.

Diodes are especially suitable for the job of the light source, light receiver
and the indicator lamp. These components are available at a low cost. The
wavelength of the light source and the indicator lamp and, respectively, the
sensitivity of the light receiver can be selected from a plurality of standard
diodes for complying with the requirements of a sewing machine according
to the invention in particular in terms of the immersion-body material
which the emitted light will pass through.
A design of the immersion body according to claim 13 is especially com-
pact.
In a sewing machine according to the invention, the oil tank is comprised
in a vertical standard of a housing where it is located behind a window
through which to see the alert signal from outside. Any lack of oil is easily
visible from outside when the indicator lamp blinks. There is no need of
any precautionary check, in close series, of the level of oil.
Another object of the invention resides in specifying an immersion body
for the oil tank of a sewing machine by which to create an oil-level moni-
toring unit for retrofitting.
According to the invention, this object is attained by an immersion body
according to claim 14.
The immersion body according to the invention is suitable for retrofitting
even the oil tanks of existing sewing machines easily and at a low cost. The
advantages of the immersion body correspond to those discussed above in
connection with the sewing machine according to the invention.

Details of the invention will become apparent from the description of pre-
ferred embodiments, taken in conjunction with the drawing, in which
Fig. 1 is an overall illustration of a sewing machine according to the in-
vention , comprising an oil tank with an oil-deficiency display ac-
cording to the invention;
Fig. 2 is an enlarged side view, partially broken away, of the oil tank ac-
cording to the invention;
Fig. 3 is a plan view of the oil tank of Fig. 2;
Fig. 4 is a perspective view of a cover of the oil tank according to Figs. 2
and 3;
Fig. 5 is a sectional view of the cover of Fig. 4 on the line V-V of Fig. 3;
Fig. 6 is a sectional view, on the line VI-VI of Fig. 3, of details of the
cover of the oil tank comprising an immersion body;
Fig. 7 is a view of the oil tank from the right in Fig. 2.
Fig. 1 is a diagrammatic side view of a sewing machine, comprising a base
plate 10 in the form of a casing, a standard 12 standing out vertically there-
from, and a horizontal arm 14 that proceeds from the top end of the stan-
dard 12 in parallel to the base plate 10. A driven arm shaft (not seen in Fig.
1) is conventionally supported in the arm 14;, a diagrammatically outlined

needle bar 15 with a needle is drivable by the arm shaft in up and down
reciprocation.
Disposed in the standard 12 is a first oil tank 16 which will be referred to in
detail below in the description. A second oil tank 18 is disposed in the cas-
ing 10. The first oil tank 16 feeds an area of needle guidance (not shown)
by way of a wick conduit 20 and a distributor 22 as well as a second wick
conduit 24.
By way of another wick conduit 26, the first oil tank 16 supplies the second
oil tank 18 with oil, the second oil tank 18 being again connected to a shut-
tle 30 via another wick conduit 28. A bottom area of the base plate 10 ac-
commodates an oilpan 32 that serves for collecting any dripping oil. This
oil is pumped, back to the distributor 22 via a conduit 34 where a pump 36
is located that is driven by a motor 38. Further details of the overall sewing
machine are of the importance in this context.
The following i s a detailed description of the oil tank 16, taken in conjunc-
tion with Figs. to 7. According to Figs. 2 and 3, the oil tank 16 has a box
frame 40, some details of the shape of which being adapted to the locally
available space as seen in Fig. 3. The oil tank 16 is fitted into a recess 42 of
a casing wall 44 of the standard 12 of the sewing machine. The box frame
40 is closed by a cover 46 that is seen in particular in Figs. 2 and 4. The
cover 46 comprises a raised area 48 of stepped ascent and a lower area 50
substantially in the form of a plate. This plate-type area 50 has two holes
52, 54 passing into tubes 56, 58 on a bottom side of the plate-type area 50.

These tubes accommodate the wick conduits 20,26 which have been men-
tioned in connection, with Fig. 1 and are shown in Figs. 2 and 7, but not in
the other illustrations.
Between the two tubes 56, 58, an immersion body 60 is fixed to the bottom
side of the plate-type area 50 of the cover 46, in particular integrally
molded on the cover 46 as a one-piece plastic piece. The immersion body
60 projects into a supplies reservoir 61 of the oil tank 16. Three holes 62,
64,66 of triangular arrangement are located in the plate-type area 50; they
are allocated to the immersion body 60, passing into corresponding re-
cesses 68, 70,72 in the top area of the immersion body 60. Two recesses
68, 70 which align with the holes 62, 64 are illustrated in Fig. 6. The third
recess 72 which aligns with the third hole 66 is seen in Fig. 5.
Apart from these recesses 68, 70, 72, the immersion body 60 is a solid
structure of transparent material, for instance' acrylic glass.
A bearing plate 74 is placed on the cover 46 in the vicinity of the immer-
sion body 60; it is in particular locked into place by the aid of a detent 76
that is integrally molded on the cover 46. Disposed on the bearing plate 74,
in positions allocated to the three recesses 68, 70, 72, are a light emitting
diode 78 as a light source, a photodiode 80 as a light receiving, diode, and
another light emitting diode 82. The photodiode 80 and the additional, light
emitting diode 112 are connected for signalling. The additional light emit-
ting diode 82 serves as an indicator lamp to be switched on and off by the
photodiode 80.
Figs. 5 and 6 are two sectional views, perpendicular to one another, of the
immersion body 60, seen on the lines V-V and VI-VI of Fig 3 The sec-

tional view of Fig, 6 shows the light emitting diode 78 and the photodiode
80. The sectional view of Fig. 5 shows the indicator lamp 82.
A bottom of the immersion body 60 comprises two slopes which incline
towards each other by approximately 45° and are designated as surfaces of
reflection 84, 8(i. A light beam 88 emitted by the light emitting diode 78
hits the first reflection surface 84. As long as the immersion body 60 is
immersed in the oil bath inside the oil tank 16, the beam runs substantially
straight through the reflection surface 84 into the oil bath as outlined by a
dot-dashed line.
When the oil bath has dropped to such an extent that the bottom of the im-
mersion body 6) lies bare, the light beam 88 is deflected by the two reflec-
tion surfaces 84, 86 in such a way that it is reflected in parallel towards the
photodiode 80. The photodiode 80 emits a switching pulse, switching on
the indicator larap 82 so that it emits a light signal.
As mentioned, the wall 90 (on the right in Figs. 2 and 3) of the box frame
40 is embedded in the recess 42 of the casing wall 44 of the sewing ma-
chine. The result is a window 92 (Fig. 1) through which the oil tank 16 be-
comes visible from outside. With the recess 42 not dimensioned for the
indicator lamp 82 to be visible directly from outside, the light beam of the
indicator lamp K2 is led through an attachment 94 of the immersion body
60 and on to a reflection surface 96, disposed by 45°, of the attachment,
from where it is reflected by 90° out of the immersion body 60 and out-
wards through the window 92. This means that the signal of the light emit-
ting diode 78 is visible from far at a characteristic place on the outside of
the sewing machine, drawing the staffs attention to the lack of oil.

It must be added that Figs.-2,4,5 and 6 show a line 98, also seen in Fig. 1,
which produces a connection between the diodes 78 to 82 and supply elec-
tronics 100.
The invention creates a compact oil-level monitoring unit which can be
used for example as a substitute in connection with a conventional oil tank.
The cover 46 ard the immersion body 60 can be injection-molded as an
integral unit. Electric connections need to be provided only as far as to the
bearing plate 74 on the top side of the immersion body 60. No movable
parts are in the oil bath, nor are there any electric or electronic lines.
As mentioned, the spatial orientation, namely the insertion of the immer-
sion body 60 from above, laterally or from below, is of no importance per
se. It is decisive that the immersion body 60 comprises a surface which is
temporarily immersed in oil when the oil tank 16 is full and which lies bare
as the oil tank 16 empties.
In any case it is advantageous that the cover 46 of the oil tank 16 or any
corresponding c overing member be injection-molded integrally with the
immersion body 60.
The shape of the immersion body 60 is of no importance either. Solely a
reflection surface is indispensable, to which to emit a light beam from the
light source i.e. from the light emitting diode 78. This can be put into prac-
tice directly or by deflection via additional reflection surfaces.
Of course, the second oil tank 18 which is disposed in the base plate 10 of
the machine can be provided with an oil-deficiency indicator or oil-level
monitoring unit according to the invention, in the same way as the oil tank

16 of the embodiment described. However, level monitoring, according to
the invention, of the top oil tank 16 is especially advantageous, provided
the oil tank 16 is connected to the bottom oil tank 18 in the way of the em-
bodiment described. The bottom oil tank 18 is connected to the top tank via
the conduit 26, md a check valve (not referenced) prevents the bottom oil
tank 18 from running over. This means that the bottom oil tank 18 will al-
ways be filled appropriately as long as there is any substantial quantity of
oil in the top oil tank 16.
In other words, monitoring the top oil tank 16 by an indicator system ac-
cording to the invention provides for the fact that both oil tanks 16,18 are
always filled adequately.

Claims
1. A sewing machine, comprising
an oil tank (16) for supply of at least one lubricating point;
characterized by
an immersion body (60) which is at least sectionally made of transpar-
ent material, projecting into a supplies reservoir (61) of the oil tank
(16) and having at least one reflection surface (84,86) accessible from
the supplies reservoir;-
a light source (78) for emitting a light beam (88) on to the reflection
surface (84, 86);
a light receiver (80) which is disposed in the beam path of the light
beam of the light source (78) that is reflected by the reflection, surface
(84, 86), the light receiver (80) being designed for triggering a switch-
ing pulse when the light beam (88) hits the light receiver (80).
2. A sewing machine according to claim 1, characterized in that the im-
mersion body (60) projects from above into the oil tank (16) and in that the
light source (781 and the light receiver (80) are located in a top area of the
immersion body (60).
3. A sewing machine according to claim 1 or 2, characterized: in that the
reflection surface (84, 86) is a plane surface of a transparent bottom area of
the immersion tody (60).
4. A sewing machine according to claim 2 or 3, characterized in that the
light source (781 and the light receiver (80) are disposed side by side in the
top area of the immersion body (60).

5. A sewing machine according to one of the preceding claims, character-
ized in that recssses (68, 70,72) for the light source (78) and the light re-
ceiver (80) are provided in the top area of the immersion body (60), the
overall immersion body (60) preferably consisting of transparent material.
6. A sewing machine according to one of the preceding claims, character-
ized in that the reflection surface (84, 86) is formed by an outer surface of
the immersion 1 ody (60).
7. A sewing machine according to one of the preceding claims, character-
ized in that two reflection surfaces (84, 86) are provided, which incline
such that the light beam that is reflected by the reflection surfaces (84, 86)
is reflected by the reflection surfaces (84, 86) in parallel to the beam of the
light source (781 back towards the light receiver (80).
8. A sewing machine according to one of the preceding claims, character-
ized in that the light source (78) and the light receiver (80) are disposed on
a bearing plate (74) which is placed on, in particular snap-engaged with,
the immersion body (60).
9. A sewing machine according to one of the preceding claims, character-
ized in that an indicator lamp (82) is provided, which is visible from out-
side and able to be switched by the light receiver (80)
10. A sewing machine according to claim 9, characterized in that the in-
dicator lamp (82) is integrated into the top area of the immersion body
(60).

11. A sewing machine according to claim 10, characterized in that the
indicator lamp (82) is located in a recess (72) in the top area of the immer-
sion body and in that the indicator lamp (82) is also mounted on the bear-
ing plate (74).
12. A sewing midline according to one of the preceding claims, charac-
terized in that the light source (78), the light receiver (80) and the indica-
tor lamp (82) are diodes.
13. A sewing machine according to one of the preceding claims, charac-
terized in that the immersion body (60) is an integral component of a
cover (46) of the oil tank (16) and in that the bearing plate (74) is fixed to
the cover (46), with the light source (78), the light receiver (80) and the
indicator lamp (32) projecting into recesses (68, 70, 72) of the immersion
body through corresponding holes (62, 64, 66) of the cover (46).
14. An immersion body (60) for use in a sewing machine according to one
of claims 1 to 13.

Abstract

An oil-deficiency indicator for sewing machines which comprise an oil
tank (16) for supply of at least one lubricating point is characterized by an
immersion body (60) which is insertable from above into the oil tank (16)
and has a bottora of transparent material; at least one reflection surface (84,
86) on the transparent bottom; a light source (78) above the reflection surface
which emits a light beam on to the reflection surface (84, 86); and a
light receiver (80) in the beam path of the light beam of the light source
(78) which is reflected by the reflection surface, releasing a switching pulse
by reception of light.

Documents:

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Patent Number

269282

Indian Patent Application Number

270/KOL/2005

PG Journal Number

42/2015

Publication Date

16-Oct-2015

Grant Date

13-Oct-2015

Date of Filing

04-Apr-2005

Name of Patentee

DURKOPP ADLER AG

Applicant Address

POTSDAMER STRASSE 190, D-33719 BIELEFELD

Inventors:

#	Inventor's Name	Inventor's Address
1	CHRISTOPH HECKNER	HEIDSIEKER HEIDE 70, D-33739 BIELEFELD
2	ANDREAS RIFFEL	HEIDEGRUNDWEG 69A, D-33689 BIELEFELD
3	JENS WATERMANN	GUTERSLOHER STRASSE 165, D-33649 BIELEFELD

PCT International Classification Number

D05C5/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102004018071.7	2004-04-08	Germany
2	102004059194.6	2004-12-09	Germany