US20180295951A1 - Portable electronic device with strap - Google Patents

Abstract

The invention proposes a portable electronic device (100) having a housing (101) and a strap (107) that is mechanically attached to the housing. The housing encompasses electronic components and protects them from ambient influences. The strap bears further electronic components (108), whereby an electrically conductive connection (301A,301B) exists between the housing and the strap. The strap is mechanically attached to the housing by means of a form-fitting connection (304), whereby the connection is oriented appropriately such that a tensile force acting on the strap in the strap's longitudinal direction generates a force component that aims to push the strap onto the housing. The strap can be mounted easily on the housing and establishes a mechanical and electrical connection between the housing and the strap in a single assembly step. The mechanical connection between the strap and the housing also resists tensile forces without forces acting on the electric contacts that might lead to a disconnection of the electrical connection between the strap and the housing.

Description

FIELD OF THE INVENTION
• The invention relates to a portable electronic device that can be worn on the body by means of the strap. The device comprises a housing that is electrically and mechanically connected to the strap.
BACKGROUND OF THE INVENTION
• Portable electronic devices that are worn on the body by means of a strap are known, for example, in the form of so-called smart watches.
• For example WO 2015/079096 A1 describes a smart watch, in which the physical activity of the user is displayed through the change of the appearance of the wrist strap of the smart watch. The change of the appearance is accomplished through electrochromic displays in the wrist strap, whose colour can be changed by application of an electrical voltage. The sensors for measuring the physical activity of the user are situated in the housing of the smart watch such that there is a need for an electrical connection between the housing and the wrist strap. However, it may well be advantageous to have individual sensors or parts of the analytical electronics situated in the strap, since the strap has pronounced contact, for example, to the arm of the user and, in particular, to the inside of the wrist. This means, again, that electrical signals and the supply of power need to be exchanged between the housing and the strap.
• Based on the aforementioned, the invention proposes a novel solution for the mechanical and electrical connection between a strap and the housing of an electronic device that is worn on the body by means of the strap.
SUMMARY OF THE INVENTION
• To solve the stated object, the invention proposes a portable electronic device having a housing and a strap that is mechanically attached to the housing. The housing encompasses electronic components and protects them from ambient influences. The strap bears further electronic components, whereby an electrically conductive connection exists between the housing and the strap. The proposed electronic device is characterised in that the strap is mechanically attached to the housing by means of a form-fitting connection, whereby the connection is oriented appropriately such that a tensile force acting on the strap in the strap's longitudinal direction generates a force component that aims to push the strap onto the housing. The proposed electronic device is advantageous in that the strap can be mounted easily on the housing and in that a mechanical and electrical connection between the housing and the strap can be produced in a single assembly step. The mechanical connection between the strap and the housing also resists tensile forces without forces acting on the electric contacts that might lead to a disconnection of the electrical connection between the strap and the housing.
• In an exemplary embodiment, the mechanical connection is secured through a latching mechanism.
• In an exemplary embodiment, the mechanical connection is secured through a rotary or sliding mechanism. In another exemplary embodiment, the strap comprises a projecting mechanical element that engages a corresponding recess in the housing. Alternatively, in another exemplary embodiment, a projecting mechanical element is provided on the housing and engages a corresponding recess in the strap.
• In an actual embodiment, the projecting mechanical element is designed in the shape of a fin or a peg. Multiple fins or pegs may be provided just as well.
• The projecting mechanical element can be a fin whose one side surface forms an angle of less than 90° with one main surface of the strap. The side surface touches against the recess such that a tensile force acting on the strap in the strap's longitudinal direction generates a force component that aims to push the strap onto the housing.
• In an exemplary embodiment, the strap comprises an electrical plug contact with a contact pin that engages a contact socket that comprises at least one contact spring in order to establish the electrical connection between the strap and the housing.
• In one exemplary embodiment, the contact pin is pushed against the at least one contact spring by the action of the tensile force acting on the strap in the strap's longitudinal direction.
• In an advantageous embodiment, the latching mechanism is designed to be detachable for disconnection of the mechanical connection between the strap and housing.
• Another exemplary embodiment provides for arranging a gasket, sections of which are conductive. The conductive sections of the gasket form contact surfaces for the electrical connection.
• In an exemplary embodiment, the gasket is arranged between the strap and the housing on surfaces that are pushed against each other by the action of a tensile force acting on the strap in the strap's longitudinal direction.
• In an advantageous exemplary embodiment, an electrical energy storage system is accommodated in the strap. The energy storage system can be a flexible battery. Both individual and multiple batteries can be used. The batteries can be rechargeable just as well as non-rechargeable. In certain applications, it may make sense to use a combination of rechargeable and non-rechargeable batteries.
SHORT DESCRIPTION OF THE FIGURES
• The drawing shows exemplary embodiments of the invention, whereby identical or corresponding elements are identified with identical or similar reference signs. In the figures:
• FIG. 1: shows a perspective view of an electronic device according to the invention;
• FIGS. 2A and 2B show the electronic device ofFIG. 1 in a partial top view from above;
• FIG. 3A shows a detail ofFIG. 1 in a partial elevation view;
• FIG. 3B shows a cross-section throughFIG. 3A;
• FIG. 3C shows a normal force decomposition;
• FIGS. 4A to 4D show design variants of a form-fitting connection between strap and housing;
• FIGS. 5A to 5D show detail views of the electrical contacts;
• FIG. 6 shows an alternative plug contact;
• FIGS. 7A to 7C show embodiments of electrical contacts; and
• FIGS. 8A to 8C show a cross-sectional view of the connection region between strap and housing.
DETAILED DESCRIPTION
• FIG. 1 shows a perspective view of anelectronic device100 that is worn on the body, in the form of a so-called smart watch. However, it needs to be noted that the invention is not limited to a smart watch, but can be used with all electronic devices that comprise a housing that is worn on the body by means of a strap as long as both a mechanical and an electrical connection is required between the housing and the strap.
• Thesmart watch100 comprises ahousing101 that protects the electronic components (not shown) of the smart watch from ambient influences such as, for example, dirt or water. Thesmart watch100 comprises adisplay102 on the upper side andcontrol elements104A and104B on along side103 of thehousing101.
• According to the present embodiment, the strap can be composed of two distinct pieces, one end of each piece being connected to the housing, the remaining ends being connected through a connecting mechanism such as a buckle, or can be composed of one piece comprising an elastic or extendable section allowing a user to extend the perimeter of the strap when putting on the smart watch.
• Astrap107 is connected to thehousing101 on theshort sides106A and106B. As a particularity, thestrap107 comprises adisplay108 which serves, for example, for matching the appearance of the smart watch to the taste of the user or for indicating, in rapidly recognisable manner, to the user additional information through certain colours without the user having to read alphanumerical information on thedisplay102. Thedisplay108 is designed, for example, as an electrochromic display. However, the invention is not limited to a certain type of display as long as thedisplay108 is well-suited for attachment on a more or lessflexible strap107. In particular, displays for alphanumerical display of information on thestrap107 can be used just as well.
• FIG. 2A shows thesmart watch100 ofFIG. 1 in a schematic top view from above, whereby only one half of thestrap107 is shown inFIG. 2A. In the exemplary embodiment shown inFIG. 2A, asingle display108 extends across the entire surface of the one half ofstrap107.
• FIG. 2B schematically shows a further exemplary embodiment of thesmart watch100 that differs from the exemplary embodiment shown inFIG. 2A in thatmultiple displays108A to108C are attached on the upper side of the one half of thestrap107.
• Thedisplays108,108A to108C are controlled electrically. For this purpose, electrical cables are provided in thestrap107 that are connected to the electronic components on the inside of thehousing101 by means of an electrical connection, such as shall be explained in more detail in the following.
• FIG. 3A shows a detail of an exemplary embodiment of thesmart watch100 in a partially elevated view. The elevated view inFIG. 3A shows electrical connectingcables301A,301B that extend from thedisplay108 toplugs302A and/or302B. The electrical connectingcables301A,301B are well-suited for conducting both electrical signals and electrical currents for the energy supply of electronic components. Theplugs302A and302B establish an electrical connection to the electronic components on the inside of thehousing101. Dashed lines at303A and303B indicate regions, in which further plugs can be arranged, if needed. Moreover, alatching mechanism304 latching thestrap107 to thehousing101 is shown. The surface of thestrap107 facing the viewer inFIG. 3A shall be called the main surface305 of thestrap107 hereinafter.Fins306,307 are arranged in the region of thestrap107 that is to be mechanically connected to thehousing101; the function of the fins will be explained in more detail in the context ofFIG. 3B.
• FIG. 3B shows a cross-section of the exemplary embodiment ofFIG. 3A along the line B-B shown inFIG. 3A. It is evident fromFIG. 3B that thewatch strap107 is placed against thehousing101 of thesmart watch100 in the arrow direction311, whereby thelatching mechanism304 snaps in and the watch strap is mechanically fixed to thehousing101. Thelatching mechanism304 prevents thewatch strap107 from detaching from thehousing101 when there are no tensile forces acting. In this context, the previously mentionedfins306 and307 engage correspondingrecesses308 and309 in thehousing101. A form-fitting connection that is additionally secured is formed between thewatch strap107 in thehousing101 by this means. The magnified detail inFIG. 3B shows thefin306engaging recess308. Moreover, the magnification shows that the side surfaces312A,312B of thefin306 are inclined and form an angle ϕ and/or ϕ′ with respect to the main surface305 that is different from a right angle.
• The tensile force is generated e.g. by a proper adjustment of the strap length to the body part to which it is to be attached, by elastic elements in the strap which tighten the strap appropriately or by other means.
• The side surfaces312A,312B of thefin306 are inclined appropriately such that they form thrust surfaces for correspondingly inclined side surfaces of the recess. Since theside surface312A has an angle of inclination of ϕ<90°, a tensile force acting between thestrap107 and thehousing101 in the direction of thearrow313 shown inFIG. 3B also has a force component314 (FIG. 3C) that pushes thefin306 and/or thestrap107 toward thehousing101 and/or onto the housing, in the manner of two interlocked fish scales. This correlation is illustrated inFIG. 3C by a normal force decomposition. Theforce component315 is received by the side surface of therecesses308 that are opposite to theside surface312A. The same applies to the effect of thefin307.
• With the height of thefin306 being 1 mm and at an angle of ϕ=75°, the resulting sinus is 0.25. This means that a tensile force of 10 Newton in the strap leads to the generation of aretention force314 of 2.5 Newton towards the inside. Simultaneously, an angle of ϕ=75° leads to a displacement of 0.15 mm of thestrap107 with respect to thehousing101 while it is being placed against it. This displacement must be taken into account in the dimensions of contact sockets and contact and, as is explained below.
• It is at the discretion of a person skilled in the art and it depends on the requirements on the electronic device whether a single fin or multiple fins are provided in a certain exemplary embodiment. Alternatively, the person skilled in the art can exchange the arrangement of fin and recess, i.e. the recess can be arranged on the strap and the fin can be arranged on the housing. Moreover, the person skilled in the art can combine the two alternatives, i.e. fin and recess are arranged to alternate on the strap and housing.
• Moreover, there is some freedom of design in the detailed provision of the fins as long as the provision of a form-fitting connection between thestrap107 and thehousing101 is ensured.FIGS. 4A to 4D show design variants of the form-fitting connection between thestrap107 and thehousing101.
• FIG. 5A shows a magnified cross-section through theplug connector302A. Theflat contact pin501 arranged on thestrap107 engages aflat contact socket502 when thestrap107 is placed against thehousing101 appropriately such that thefins306,307 engage therecesses308,309. When thestrap107 is placed in thehousing101, the strap performs a small longitudinal motion due to the side surfaces of the fins inFIG. 5A being inclined (towards the left inFIG. 5A). To permit said longitudinal motion, allcontact sockets502 on the housing are wider than the contact pins5011strap107. In the actual case shown inFIG. 5A, the right edge of thecontact pin501 is flush with the right edge of thecontact socket502, whereas a gap remains between the left edges of thecontact pin501 and/orcontact socket502, when the left edges of thefins306,307 are flush with the left edges of therecesses308,309. In the example mentioned, with the height of the fins being 1 mm and an angle (1)=75°, said gap is approximately 0.15 mm. When thestrap107 is placed against thehousing101, thecontact pin501 moves from the right edge of thecontact socket502 towards the contact socket's left edge.
• FIG. 5B shows a cross-sectional view through thecontact socket502 along the line A-A inFIG. 5A. As is evident fromFIG. 5B, thecontact socket502 comprises aspringy groove503 in order to establish good electrical contact to thecontact pin501. Thecontact socket502 is connected to the electrical components on the inside of thehousing101 by anelectrical conductor504.
• As an alternative to the cambered form of the contact socket shown inFIGS. 5A and 5B, the spring effect can be attained in another exemplary embodiment by mounting the contact socket while it is in a pretensioned state. Thecontact socket502 comprises one or two electrical contact surfaces, whereby at least one exerts the aforementioned spring effect on thecontact pin501. As an alternative to the embodiments described above, the spring effect can also be attained through acambered contact pin501.
• Gaskets504 are provided on thestrap107 and protect the electrical contact region from dirt and moisture when thestrap107 is inserted into the housing101 (FIG. 5D).
• FIG. 5C shows a top view of thecontact socket502 without (left) and withcontact pin501 plugged in (right). Lastly,FIG. 5D shows the situation, in which thestrap107 is inserted into thehousing101.
• FIG. 6 shows another alternative embodiment of the electrical contacts betweenstrap107 and housing11. In this embodiment, the contact pins501 are provided to be round and are pushed successively against springy contacts in the contact sockets due to the thrust surfaces between thefins306,307 and recesses308,309 being inclined, as is evident fromFIG. 6.
• The use of a pluggable element such as a pin further secures the connection between strap and housing.
• FIGS. 7A to 7C show further alternative embodiments of the electric contacts, in which the electrical contact is provided by a compressive force between the pairs of contacts. In the variants shown inFIGS. 7A to 7C, the installation height decreases successively starting from ashort pin701 with socket702 (FIG. 7A) via twocontacts703 that are provided in the form of an elevation (FIG. 7B) to twocontact surfaces703,704, wherebyonly contact surface703 is provided as an elevation (FIG. 7C).
• In yet another variant, thegasket504 is used as a contact. Thegasket504 is produced, in alternating manner, from conductive elastic material and insulating elastic material. The conductive sites thus also serve as contacts. However, a contact of this type requires a reliable retention force over the entire length of the gasket. Electrically conductive rubber materials that are suitable for this purpose are commercially available and are used mainly in the area of EMC and in keys. They make sense when the signal currents are small. The shape of the contacts integrated into thegasket504 must be appropriate for unambiguous and precise mounting such that the conductive sites are placed on each other correctly.
• In the figures of the drawing, the contacts have been shown magnified on purpose such the workflows of inserting, guiding through fins and recess and the latching of the latching mechanism take place independent of each other and consecutively for improved illustration. In one practical embodiment, fins with a height of 0.5 mm and contacts with a length of 0.5 mm have proven to be expedient.
• FIG. 8 shows thelatching mechanism304 in more detail. Thelatching mechanism304 comprises aspring tongue801 with ahook802. Thespring tongue801 is firmly connected to thestrap107. Different types of attachment, such as welding, gluing or the like, are conceivable for this purpose. Moreover, thespring tongue801 and thestrap107 can be produced in the form of a single part. In this context, the spring effect is generated by thespring tongue801 as such or in the connecting site between thespring tongue801 andstrap107. Thehousing101 has an undercutrecess803 provided in it, which is engaged by thespring tongue801 when thestrap107 is placed against thehousing101. Therecesses803 comprise a latchingsurface804. In the fully inserted stage shown inFIG. 8C, thehook802 of thespring tongue801 reaches behind the latchingsurface804. When thespring tongue801 is latched into therecess803, it can be detached again only by inserting atool806. In this context, thetool806 pushes thespring tongue801 away from the latchingsurface804 against the acting spring force such that thespring tongue801 gets released and thestrap107 can be taken off the housing.
• It is insignificant for the invention at which site thelatching mechanism304 is provided. Moreover, more than asingle latching mechanism304 can be provided just as well. A person skilled in the art is aware and will select for the individual application further latching mechanisms, including those that can be released without a tool or those that are fixed by means of a rotary or sliding motion.
• Finally, an exemplary embodiment of the invention can also have an electrical energy store accommodated in the strap, for example one or more battery or batteries. In particular, the energy store can be provided in the form of a flexible battery. The one or more battery or batteries are primary or secondary batteries. The batteries are connected, for example, to the electronic components in thehousing101 by means of the electrical connectingcables301A,301B.

• List ofreference numbers

  100	Smart watch	313	Tensile force
  101	Housing	314	Force
  102	Display	315	Force
  101	Long side of thehousing	501	Contact pin
  104A,104B	Control elements		502	Contact socket
  107	Strap	503	Groove
  108	Display	504	Gasket
  108A to 108C	Displays	701	Contact pin
  301A, 301B	Connecting cables	702	Contact socket
  302A,302B	Plug		703	Elevated contact surface
  304	Latching mechanism	704	Contact surface
  305	Main surface	801	Spring tongue
  306, 307	Fin	802	Hook
  308, 309	Recesses	803	Recess
  311	Arrow	804	Covered surface
  312A, 312B	Side surfaces of thefin	806	Tool

Claims (13)

1. A portable electronic device having a housing and a strap that is mechanically attached to the housing, whereby the housing encompasses electronic components;

wherein the strap is mechanically attached on at least one of its ends to the housing by means of corresponding interlocking mechanical elements forming a form-fitting connection, whereby said corresponding mechanical elements comprise respective thrust surfaces oriented appropriately such that a tensile force acting on the strap in the strap's longitudinal direction and away from said housing generates a force component orthogonal to said longitudinal direction that aims to push the strap onto the housing.

2. The device according toclaim 1, wherein the mechanical connection is secured through a latching mechanism.

3. The device according toclaim 1, wherein the mechanical connection is secured through a rotary or sliding mechanism.

4. The device according toclaim 1, wherein the strap comprises a projecting mechanical element that engages a corresponding recess in the housing.

5. The device according toclaim 1, wherein a projecting mechanical element is provided on the housing and engages a corresponding recess in the strap.

6. The device according toclaim 4, wherein the projecting mechanical element is designed in the shape of a fin or a peg.

7. (canceled)

8. The device according toclaim 6, wherein the projecting mechanical element is a fin whose one side surface and a main surface of the strap form an angle smaller than 90°, in that the side surface touches against the recess such that a tensile force acting on the strap in the strap's longitudinal direction generates a force component that aims to push the strap on to the housing.

9. The device according toclaim 1, wherein the strap bears further electronic components; and whereby an electrically conductive connection exists between the housing and the strap;

and the strap comprises an electrical plug contact with a contact pin that engages a contact socket that comprises at least one contact spring in order to establish the electrical connection between the strap and the housing.

10. The device according to claim98, wherein the contact pin is pushed against the at least one contact spring by the action of the tensile force acting on the strap in the strap's longitudinal direction.

11. The device according toclaim 2, wherein the latching mechanism is designed to be detachable for disconnection of the mechanical connection between the strap and housing.

12. The device according toclaim 8, wherein a gasket, sections of which are conductive, is arranged between the strap and the housing, whereby the conductive sections of the gasket form contact surfaces for the electrical connection.

13. The device according toclaim 11, wherein the gaskets are arranged between the strap and the housing on surfaces that are pushed against each other by the action of a tensile force acting on the strap in the strap's longitudinal direction.

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