GB2505152A - Hand Operated bed force sensing speed control of an Electric Sewing machine - Google Patents
Hand Operated bed force sensing speed control of an Electric Sewing machine Download PDFInfo
- Publication number
- GB2505152A GB2505152A GB201210584A GB201210584A GB2505152A GB 2505152 A GB2505152 A GB 2505152A GB 201210584 A GB201210584 A GB 201210584A GB 201210584 A GB201210584 A GB 201210584A GB 2505152 A GB2505152 A GB 2505152A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pressure
- sewing machine
- sensitive resistor
- resistor element
- support member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05B—SEWING
- D05B69/00—Driving-gear; Control devices
- D05B69/14—Devices for changing speed or for reversing direction of rotation
- D05B69/18—Devices for changing speed or for reversing direction of rotation electric, e.g. foot pedals
-
- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05D—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES D05B AND D05C, RELATING TO SEWING, EMBROIDERING AND TUFTING
- D05D2205/00—Interface between the operator and the machine
- D05D2205/02—Operator to the machine
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Textile Engineering (AREA)
- Sewing Machines And Sewing (AREA)
Abstract
A system for regulating the stitching speed of an electrically-operated sewing machine (B) by mans of pressing down on the machine bed or throat area (30). The system comprises a resilient support member preferably a foot (1) attached to the underside of the base (32) of the machine (B) such that it contacts a support surface (33) when downward pressure is applied to the machine bed. This resulting compression causes a change in resistance in the force-sensitive resistor element (7) which is connected to the electrical motor to modulate the motor speed.
Description
Hand operated speed control of an electric sewing machine The present invention relates to a hand operated system for controlling or varying the stitching speed of an electric sewing machine. More particularly, it relates to a system for controlling or varying the stitching speed of an electric sewing machine which is actuated by pressure applied by the fingers, the hands or the lower arms of the operator of the sewing machine.
Background of the Invention
In a conventional electrically-operated sewing machine, an electric motor is connected to means for controlling the operation of the needle assembly and, separately, the operation of the shuttle assembly and also the linkages that operate the feed dog mechanism which advances the fabric being sewed. The movements of these various components are synchronised no matter how fast the motor is turning. The speed of the motor is conventionally controlled by a pressure-sensitive foot-operated pedal or a knee-operated lever such that increased pressure exerted on the foot-operated pedal or the knee-operated lever causes an increase in the speed of the motor and, thereby, an increase in the speed of the needle assembly, the shuttle assembly and the feed dog. The use of a foot-operated pedal or of a knee-operated lever to control the speed of the motor enables an experienced operator to use his or her hands to guide the workpiece being sewed. Unfortunately, operators who are not able to use foot-operated pedals or knee-operated levers or those who do not have, or who are unable to achieve, the high level of co-ordination skills required to use such pedals or levers are disadvantaged by such machines. Indeed, when beginners learn to sew using such electric sewing machines, they often find it difficult to co-ordinate pressing a foot pedal at the same time as guiding the workpiece with the hands. This lack of control results in poor quality stitching, such as achieving irregular stitch length and/or stitching out of line.
JP 9253373A discloses a sewing speed controller for a sewing machine which enables the machine operator to vary the sewing speed by the application of hand pressure on a plate-like pressure sensitive variable resistor provided as a throat plate on a sewing machine bed. The sensor plate, according to this prior art document, is relatively large. The document recognises that a large pressure-sensitive area is required for effective control and to prevent the user from moving his or her hands off the edge of the sensor when guiding the workpiece. However, because only the small mass of the hand is involved, natural involuntary fluctuations in hand pressure on the sensor plate adversely affect the consistency of the motor speed thus causing the operation of the machine to be intermittent or the sewing speed of the machine to vary uncontrollably. As such, workpiece quality is compromised.
Additionally, the provision of a large area pressure-sensitive plate in the machine disclosed in JP 9253373A increases the production costs of the machine.
It is an object of the present invention to provide a system for use in connection with an electrically-operated sewing machine which overcomes the problems of the prior art by enabling the speed of the motor of the sewing machine to be controlled at a consistent speed yet one that can be varied easily by the application of pressure by the fingers, hands or lower arms of the operator without the need to apply substantial force. Additionally, the system of the present invention does not require the provision of a separate pressure-sensitive plate incorporated into the sewing machine bed since the sewing machine bed itself is rendered sensitive to pressure by means of the use of the system.
Accordingly, the present invention provides a system for controlling the stitching speed of an electrically-operated sewing machine which system comprises a support member formed of a resilient material for attachment to the underside of the sewing machine such that it contacts a support surface upon which the sewing machine is positioned and a pressure-sensitive resistor element adapted to be connected into the electrical circuit for the motor of the sewing machine, said pressure-sensitive resistor element being located in the support member or above the support member and in working co-operation therewith and wherein, in use, pressure exerted on the bed or throat area of the sewing machine causes the system to be pressed onto the support surface resulting in a change in electrical resistance in the pressure-sensitive resistor element and, thereby, a change in the stitching speed. Preferably, the exertion of pressure on the system of the invention results in a decrease in electrical resistance in the pressure-sensitive resistor element and, thereby, an increase in the stitching speed.
The present invention further provides an electrically-operated sewing machine having attached, to its underside, a system of the invention as mentioned above and wherein the pressure-sensitive resistor element of the system is connected into the electrical circuit for the motor of the sewing machine.
It will be apparent from the above that the system of the present invention makes use of the mass of the sewing machine to provide a load on the pressure-sensitive resistor element, unlike the system employed in JP9253373A. By exploiting the sewing machine mass through the system of the invention in this way, it is possible for the operator of the machine to control the machine to attain consistent sewing speed yet change the sewing speed simply by pressing down lightly on the machine bed, for instance through the workpiece as this is being guided.
The system of the invention comprises, as stated above, a support member. The support member may be a foot or a pad. Preferably, if the sewing machine is provided with conventional load bearing feet for supporting the sewing machine stably on a supporting surface, such as a table or workbench, the support member will have a dimension such that, when attached to the underside of the sewing machine and when no pressure is applied to the machine bed, the support member does not extend to make contact, or complete contact, with the supporting surface but ends slightly above the supporting surface. By such an arrangement, the application of only slight pressure to the machine bed causes complete contact of the support member with the supporting surface. Alternatively, the support member may remain in contact with the supporting surface and in such a configuration it may be necessary to ensure that the pressure so exerted on the pressure-sensitive resistor element is less than the activation pressure of the system (which can be adjusted by the use of one or more appropriate resistors, such as variable resistors, in the electrical circuit for the sewing machine motor).
The support member is formed of a resilient material. Examples of resilient materials that may be employed in the manufacture of the support member include elastomeric materials, felt and foamed polymeric materials. In one embodiment of the invention, the support member is formed of natural rubber or a synthetic rubber. In another embodiment of the invention, the support member is formed of felt.
The system of the present invention also comprises a pressure-sensitive resistor element. By the term "pressure-sensitive resistor element" I mean a component, having a pressure-sensitive area, for incorporation into an electrical circuit which provides electrical resistance to the passage of an electric current through the component wherein the degree of resistance provided is responsive to external compression on the pressure-sensitive area of the component. Pressure-sensitive resistor elements are well-known and are easily available commercially.
Examples of pressure-sensitive resistor elements include force sensitive resistors and sprung or pressure-activated rheostats. According to the circuit used to connect the pressure-sensitive resistor element into electrical circuit for the sewing machine motor, the application of external pressure to the pressure-sensitive area of a pressure-sensitive resistor element can be made either to decrease the electrical resistance or increase the electrical resistance to bring about a change in the stitching speed of the machine. Preferably, however, pressure exerted on the pressure-sensitive area of the pressure-sensitive resistor element will result in a decrease in electrical resistance in the pressure-sensitive resistor element and, correspondingly, an increase in the stitching speed of the machine. A typical force sensitive resistor comprises a layer of an electrically-insulating rubbery elastomer containing dispersed uniformly therein an electroconductive particulate material which layer is placed between two opposite, flexible, electrodes. External pressure applied to such a construction causes the electroconductive particles to touch and to contact the electrodes, changing the resistance of the layer. Thus, according to such a construction, the resistance is inversely proportional to the force applied, i.e. the resistance decreases as the applied pressure increases.
The pressure-sensitive resistor element may be incorporated into the support member, for example provided within a foot that may be attached to the underside of the sewing machine. Alternatively, the pressure-sensitive resistor element may be provided, when attached to a sewing machine, above the support member such that it co-operates with the support member. In such a configuration, the pressure-sensitive resistor element may be held in close contact against the undersurface of the sewing machine or even located within a recess provided within the underside casing of the sewing machine. In any configuration, it is, of course, necessary that the support member and the pressure-sensitive resistor element are able to co-operate together, i.e. the support member is able to exert a pushing force against the pressure-sensitive area of the pressure-sensitive resistor element.
According to one embodiment of the invention, the pressure-sensitive area of the resistor element is in contact with the underside of the sewing machine and, on its opposite side, is in direct contact with the support member. According to a different embodiment, the pressure-sensitive area of the resistor element is in contact with the underside of the sewing machine and, on its opposite side, is in direct contact with one side of a layer of non-resilient material, typically a layer of a non-resilient plastics material, and the support member is in direct contact with the other side of the layer of non-resilient material. By the use of such a layer of non-resilient material in this embodiment, the upward force exerted by the support member, when the machine is pressed down on a supporting surface, is more specifically directed onto the pressure-sensitive area of the pressure-sensitive resistor element. Additionally, if the layer of non-resilient material has one or more portions which are remote from the portion that is in contact with the sensitive area of the resistor element then the one or more remote portions can be attached directly to the underside of the sewing machine so as to hold the pressure-sensitive area of the resistor element in close contact with the underside of the sewing machine thereby avoiding the need to attach the resistor element itself directly to the underside of the sewing machine. If a layer of non-resilient material is used to separate the pressure-sensitive area of the resistor element from direct contact with the support member, this may conveniently be in the form of a disc of non-resilient material having a diameter which is not greater than the diameter of the pressure-sensitive area of the resistor element. The disc of non-resilient material, if used, may have one or more portions extending outwardly from the disc which may be used, as described above, for attaching the layer to the underside of the sewing machine.
The pressure-sensitive resistor element, in use, will be connected into the electrical circuit for the motor of the sewing machine. The person skilled in the art of electrical circuits will know how this may be achieved. Typically, the pressure-sensitive resistor element may be connected in a potential divider circuit with a fixed resistor or a rheostat whose resistance can be altered in order to adjust the sensitivity of the pressure-sensitive resistor element, such as is mentioned above in the case when the support member may be attached to the sewing machine so as to provide a permanent, load bearing contact with a supporting surface. An electrical circuit involving an operational amplifier, transistor and diode will typically be used to enable variable motor speed control using the pressure-sensitive resistor element.
The pressure-sensitive resistor element of the system of the invention will be connected into the electrical circuit for the motor of the sewing machine to enable the system to operate. It may, for instance, be connected internally in the sewing machine. Alternatively, the appropriate circuitry can be arranged in an external control box for connection to a source of electric current, and the sewing machine would be connected to the output of the control box.
In order that the invention can be fully understood and readily carried into effect, various embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, of which:-Figure 1 is a diagrammatic side cross-section view of an embodiment of the invention; Figure 2 is a diagrammatic side cross-section view of a different embodiment of the invention; Figure 3 is a diagrammatic side view of yet a further embodiment of the invention; Figure 4 is a diagrammatic side cross-section view of yet a different further embodiment of the invention; Figure 5 is an exploded view of the embodiment shown in Figure 3; Figure 6 is a diagrammatic side view of an electric sewing machine having the system of the Figure 3 attached to its underside.
Figure 7 is an underside view of the sewing machine shown in Figure 6.
Figure 8 is a side view of a sewing machine comprising the system of the Figure 3 which is arranged such that the toot does not contact the supporting surface when the machine is at rest; Figure 9 is a side view of the sewing machine shown in Figure 8, when in use, with the toot contacting the supporting surface; and Figure 10 is a diagram showing an electrical circuit for use in the present invention for connecting the pressure-sensitive resistor element of the system to the electric motor of the sewing machine.
As shown in Figure 1, the system of the present invention comprises a foot 1. This is shown attached to the underside 2 ot an electrically-operated sewing machine. The foot 1 has a shape which is generally frustoconical but with a slightly rounded lower edge for contact with a work surface 3 upon which the sewing machine is positioned for use.
The foot 1 is attached to the underside 2 of the sewing machine by an outwardly extending lug 4 tormed integrally with the foot. Attachment to the underside of the sewing machine may be achieved by the use of an adhesive. The foot 1 has a central, circular portion 5 which is separated from the lug 4 by a concentric recess 6. The central portion 5 of the foot is in direct contact with a force-sensitive resistor 7 which is housed in a recess tormed into the base of the sewing machine.
As shown in Figure 2, the embodiment comprises a sprung rheostat, i.e. a pressure-activated rheostat 8.
As shown in Figure 3, the embodiment comprises a toot 1 which, at its bottom, is in contact with a supporting surface 3 and which, at its top, is in contact with and is attached to a non-resilient plastic disc 9. The disc 9 has a remote portion 10 in the form of a ring concentric with the disc 9. The disc 9 contacts a force-sensitive resistor 7 which, itselt, is housed in a recess in the base or underside 2 of the sewing machine casing. The diameter of disc 9 is smaller than the diameter of the force-sensitive resistor 7 such that it presses directly onto the force-sensitive resistor 7.
The components may be attached together and to the underside 2 of the sewing machine by the use of one or more types of adhesive compositions, i.e. the foot 1 is adhered to the disc 9 and the remote portion 10 of the disc may be adhered to the base or underside 2 of the sewing machine thus holding the force-sensitive resistor tightly in the recess and in contact with the underside of the sewing machine.
As shown in Figure 4, the support member is provided as a pad 11 of felt attached to the underside of the sewing machine. The felt pad 11 holds in place a force-sensitive resistor 7 which is maintained in direct contact with the underside 2 of the sewing machine. In such an embodiment, the felt pad may extend across a large area of the base of the sewing machine while the force-sensitive resistor is located towards the front and/or side of the base.
The embodiment of the system shown in Figure 3 is shown in the exploded view in Figure 5. As shown, disc 9 is sandwiched between the top surface of the foot 1 and the force-sensitive resistor 7. The disc 9 has a remote portion 10 in the form of a flat ring concentric with the disc which is connected to the disc.
Figure 6 shows a side view of an electrically-operated sewing machine A having a machine bed 20 and having attached to its base 22 a sensor system 21 of the type illustrated in Figure 3 which contacts a flat supporting surface 23. The sewing machine is stably supported on the supporting surface 23 by conventional, load-bearing feet 24 attached to the underside 22 of the machine. As shown in Figure 7, which is an underside view of the sewing machine shown in Figure 6, the conventional, load-bearing feet 24 are arranged so as to support the machine in a stable manner on a flat supporting surface. The sensor system 21, in the embodiment shown in Figures 6 and 7, is positioned centrally on the front underside of the machine A such that it is responsive to pressure exerted downwards on the machine bed 20.
Figure 8 shows a side view of an electrically-operated sewing machine B having a machine bed 30 and having attached to its base 32 a sensor system 31 of the type illustrated in Figure 3 but wherein the foot 1 of the sensor system, when the machine is at rest, is not in contact with a flat supporting surface 33 but, instead, is held slightly above the surface 33. The weight of the machine B, in this embodiment, is supported stably by conventional feet 34 attached to the base 32 of the machine. As shown in Figure 9, the application of light pressure F downwards on machine bed 30, such as by the fingers of the machine operator, causes the sensor system 31 to came into contact with the supporting surface 33 and, thereby, create a pushing force upwards from the foot 1 to the force-sensitive resistor 7 of the sensor system 31.
Figure 10 shows, by way of example only, a circuit diagram that may be used for connecting the pressure-sensitive resistor element to the electric motor of an electrically-operated sewing machine. In the circuit diagram, the abbreviations shown have the following meanings: SW1 -circuit switch FSR1 -force-sensitive resistor (Tekscan "FlexiforcelM" A21 2) Ri -resistor (10K) lola -operational amplifier LM358 R2 -resistor (10K) Qi -11P121 transistor Di -diode MT1 -sewing machine motor
Claims (10)
- CLAIMS1. A system for controlling the stitching speed of an electrically-operated sewing machine which system comprises a support member formed of a resilient material for attachment to the underside of the sewing machine such that it contacts a support surface upon which the sewing machine is positioned and a pressure-sensitive resistor element adapted to be connected into the electrical circuit for the motor of the sewing machine, said pressure-sensitive resistor element being located in the support member or above the support member and in working co-operation therewith and wherein, in use, pressure exerted on the bed or throat area of the sewing machine causes the system to be pressed onto the support surface resulting in a change in electrical resistance in the pressure-sensitive resistor element and, thereby, a change in the stitching speed.
- 2. A system according to claim 1, wherein, in use, pressure exerted on the bed or throat area of the sewing machine causes the system to be pressed onto the support member resulting in a decrease in electrical resistance in the pressure-sensitive resistor element and, thereby, an increase in the stitching speed.
- 3. A system according to either claim 1 or claim 2, wherein the support member is a foot.
- 4. A system according to any one of claims 1 to 3, wherein the support member is formed of natural or synthetic rubber, felt or foamed polymeric material.
- 5. A system according to any one of claims 1 to 4, wherein the pressure-sensitive are of the pressure-sensitive resistor element is in contact with the underside of the sewing machine and is separated from the support member by a layer of non-resilient material.
- 6. A system according to claim 5, wherein the layer of non-resilient material is formed ota plastics material.
- 7. A system according to either claim 5 or claim 6, wherein the layer of non-resilient material comprises a disc and the pressure-sensitive resistor element has a substantially circular pressure-sensitive area, wherein the disc has a diameter not greater than the diameter of the substantially circular pressure-sensitive area of the pressure-sensitive resistor element.
- 8. A system according to any one of claims 1 to 7, wherein the pressure- sensitive resistor element is a force-sensitive resistor or a pressure-activated rheostat.
- 9. An electrically-operated sewing machine having attached, to its underside, a system of any one of claims 1 to 8 and wherein the pressure-sensitive resistor element of the system is connected into the electrical circuit for the motor of the sewing machine.
- 10. An electrically-operated sewing machine according to claim 9, having more than one system of any one of claims 1 to 7 attached, wherein each pressure-sensitive resistor element is connected into the electrical circuit for the motor of the sewing machine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB201210584A GB2505152A (en) | 2012-06-14 | 2012-06-14 | Hand Operated bed force sensing speed control of an Electric Sewing machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB201210584A GB2505152A (en) | 2012-06-14 | 2012-06-14 | Hand Operated bed force sensing speed control of an Electric Sewing machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201210584D0 GB201210584D0 (en) | 2012-08-01 |
| GB2505152A true GB2505152A (en) | 2014-02-26 |
Family
ID=46640936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB201210584A Withdrawn GB2505152A (en) | 2012-06-14 | 2012-06-14 | Hand Operated bed force sensing speed control of an Electric Sewing machine |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2505152A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4150634A (en) * | 1978-05-19 | 1979-04-24 | The Singer Company | Integrated motor controller for sewing machines |
| US4217841A (en) * | 1978-04-06 | 1980-08-19 | Koyo Seiko Company Limited | Speed control apparatus for use with electric sewing machine |
| JPS5833993A (en) * | 1981-08-20 | 1983-02-28 | Brother Ind Ltd | Speed instructing device for motor |
| JPH09253373A (en) * | 1996-03-25 | 1997-09-30 | Hitachi Electron Service Co Ltd | Sewing speed controller for sewing machine |
| US6959657B1 (en) * | 2004-03-10 | 2005-11-01 | Duval Richard J | Optical stitch regulator system |
-
2012
- 2012-06-14 GB GB201210584A patent/GB2505152A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4217841A (en) * | 1978-04-06 | 1980-08-19 | Koyo Seiko Company Limited | Speed control apparatus for use with electric sewing machine |
| US4150634A (en) * | 1978-05-19 | 1979-04-24 | The Singer Company | Integrated motor controller for sewing machines |
| JPS5833993A (en) * | 1981-08-20 | 1983-02-28 | Brother Ind Ltd | Speed instructing device for motor |
| JPH09253373A (en) * | 1996-03-25 | 1997-09-30 | Hitachi Electron Service Co Ltd | Sewing speed controller for sewing machine |
| US6959657B1 (en) * | 2004-03-10 | 2005-11-01 | Duval Richard J | Optical stitch regulator system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201210584D0 (en) | 2012-08-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |