| JP2000234742 | COOKER |
| JP04061834 | TOASTER OF ELECTRONIC RANGE EQUIPPED WITH TOASTER |
| JP3728761 | OVEN TOASTER |
Lam, Chun Fai (20/F, Chinachem Holliwood Centre 1-13 Hollywood Roa, Central Hong Kong, CN)
Yip, Chung Lik Thomas (1A No 4 Silverstar Path, Silverstrand Clearwater Bay, Hong Kong, CN)
Lam, Chun Fai (20/F, Chinachem Holliwood Centre 1-13 Hollywood Roa, Central Hong Kong, CN)
| 1. | A carriagedescending mechanism for an electric toaster, comprising: an activation bar depressible by a user throughout a short displacement to cause a bread supporting carriage of the toaster to descend, an activation arm extending from a primary pivot axis in the toaster to the activation bar, a primary gear upon the primary pivot axis and pivotal thereabout in unison with the arm, a secondary gear upon a secondary pivot axis in the toaster and meshing with the primary gear, a carriage arm extending from the second pivot axis and moving in unison with the secondary gear, wherein the carriage arm and moves the carriage throughout a large displacement upon said short displacement of the activation bar. |
| 2. | The mechanism of Claim 1, wherein the primary gear comprises primary teeth at a large radius from the primary pivot axis and the secondary gear comprises secondary teeth at a small radius from the secondary pivot axis. |
| 3. | The mechanism of Claim 1, further comprising a torsion spring surrounding the primary pivot axis and biasing the activation arm into a raised rest position. |
| 4. | The mechanism of Claim 1, further comprising an intermediate link connecting a distal end of the carriage arm to the carriage. |
| 5. | A mechanism for moving a heating element within a toaster, the heating element being substantially planar and vertically oriented within the toaster, the mechanism comprising: a first arm pivotal about a horizontal axis adjacent to the heating element and driven by a motor to pivot throughout an acute angle about the horizontal axis, the arm having a distal end attached pivotally to and supporting the heating element. |
| 6. | The mechanism of Claim 5, wherein the distal end of the arm is attached pivotally to the heating element in a position of the heating element that is substantially midway between the top and bottom of the heating element. |
| 7. | The mechanism of Claim 5, further comprising a plate having an arcuate slot therein and wherein there is provided a pin at the distal end of the first arm that is guided within the arcuate slot. |
| 8. | The mechanism of Claim 5, further comprising a second arm forming a parallelogram linkage with the first arm. |
| 9. | The mechanism of Claim 8, wherein the parallelogram linkage comprises a top link interacting with the heating element and the extending between respective distal ends of the first and second arms. |
| 10. | The mechanism of Claim 5, further comprising a clamp for pushing the heating element to a rest position after toasting. |
| 11. | The mechanism of Claim 5, further comprising a rod at the horizontal pivot axis and a torsion spring surrounding the rod/ the torsion spring having a first leg bearing against a fixed part of the toaster and the second leg bearing against the first arm. |
| 12. | The mechanism of Claim 11, wherein the torsion spring has numerous windings such that the first leg bears against the first arm with substantially even force throughout pivotal movement of the first arm. |
| 13. | The mechanism of Claim 9, further comprising a device for maintaining a substantially vertical orientation of the heating element upon pivotal movement of the first arm, the device comprising a lever attached to the heating element and having a boss extending therefrom and through a boundary aperture of the top link, and further comprising a pin at the distal end of the first arm and a leaf spring extending about the pin and interacting with the top link and lever for biasing the lever. |
Background of the Invention
The present invention relates to electric toaster mechanisms. More particularly, although not exclusively, the invention relates to an electric toaster having an activation bar amplification mechanism enabling the bread carriage to translate throughout a large movement upon small movement of the activation bar. The invention also relates to a toaster having a swing movement heating element that bears even pressure against bread in the toaster with little force variation for various bread thicknesses. Another aspect of the invention resides in maintaining vertical a moving heating element during pivotal movement of its activation mechanism. A further aspect of the invention resides in minimising the reaction force of the activation bar despite the ability of the amplification mechanism to enable the bread carriage to translate throughout a large movement upon small movement of the activation bar.
There are many toasters on the market and most employ inexpensive and crude mechanisms to move the bread carriage. Most mechanisms have a one-to-one movement
ratio between the activation bar and the bread carriage. Most mechanisms employ crude coil spring carriage return mechanisms that scrape and grind emanating an audible cheapness from the toaster.
Recent, more sophisticated toasters have horizontally moving heating elements that slide linearly against high fictional forces. In the present invention, the heating elements themselves would typically be massive glass panel heaters and such sliding friction ought to be avoided.
Objects of the Invention
It is an object of the present invention to provide mechanisms for a high-quality toaster.
Disclosure of the Invention
There is disclosed herein a carriage-descending mechanism for an electric toaster, comprising: an activation bar depressible by a user throughout a short displacement to cause a bread- supporting carriage of the toaster to descend, an activation arm extending from a primary pivot axis in the toaster to the activation bar,
a primary gear upon the primary pivot axis and pivotal thereabout in unison with the arm, a secondary gear upon a secondary pivot axis in the toaster and meshing with the primary gear, a carriage arm extending from the second pivot axis and moving in unison with the secondary gear, wherein the carriage arm and moves the carriage throughout a large displacement upon said short displacement of the activation bar.
Preferably, the primary gear comprises primary teeth at a large radius from the primary pivot axis and the secondary gear comprises secondary teeth at a small radius from the secondary pivot axis.
Preferably, the mechanism further comprises a torsion spring surrounding the primary pivot axis and biasing the activation arm into a raised rest position.
Preferably, the mechanism further comprises an intermediate link connecting a distal end of the carriage arm to the carriage.
There is further disclosed herein a mechanism for moving a heating element within a toaster, the heating element being substantially planar and vertically
oriented within the toaster, the mechanism comprising: a first arm pivotal about a horizontal axis adjacent to the heating element and driven by a motor to pivot throughout an acute angle about the horizontal axis, the arm having a distal end attached pivotally to and supporting the heating element.
Preferably, the distal end of the arm is attached pivotally to the heating element in a position of the heating element that is substantially midway between the top and bottom of the heating element.
Preferably, the mechanism further comprises a plate having an arcuate slot therein and wherein there is provided a pin at the distal end of the first arm that is guided within the arcuate slot.
Preferably, the mechanism further comprises a second arm forming a parallelogram linkage with the first arm.
Preferably, the parallelogram linkage comprises a top link interacting with the heating element and the extending between respective distal ends of the first and second arms.
Preferably, the mechanism further comprises a clamp
for pushing the heating element to a rest position after toasting.
Preferably, the mechanism further comprises a rod at the horizontal pivot axis and a torsion spring surrounding the rod, the torsion spring having a first leg bearing against a fixed part of the toaster and the second leg bearing against the first arm.
Preferably, the torsion spring has numerous windings such that the first leg bears against the first arm with substantially even force throughout pivotal movement of the first arm.
Preferably, the mechanism further comprises a device for maintaining a substantially vertical orientation of the heating element upon pivotal movement of the first arm, the device comprising a lever attached to the heating element and having a boss extending therefrom and through a boundary aperture of the top link, and further comprising a pin at the distal end of the first arm and a leaf spring extending about the pin and interacting with the top link and lever for biasing the lever.
Brief Description of the Drawings
A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:
Fig. 1 is a schematic elevation of a carriage- descending mechanism for a toaster,
Fig. 2 is a schematic elevation of a parallelogram linkage for moving a toaster the heating element,
Fig. 3 is a schematic elevation of parts of the parallelogram linkage of Fig. 2 including a heater- loading torsion spring,
Fig. 4 is a schematic cross-sectional plan view of the parallelogram linkage top mechanism and associated heated vertical-maintain device,
Fig. 5 is a schematic elevation of the vertical- maintain device of Fig. Numeral for, and
Fig. 6 is a repeat of Fig. 1, but showing an activation bar return spring.
Description of the Preferred Embodiment
In Fig. 1 of the accompanying drawings there is depicted schematically an activation bar 10 of an electric toaster. This bar is pushed downwardly by a user to effect downward movement of a loaded bread carriage. The mechanism is aimed at achieving full displacement of the bread carriage upon minimal displacement of the activation bar. The activation bar 10 is located at the end of an activation arm 11. Arm 11 is pivotally mounted to the toaster at pivot axis 14. Extending from pivot axis 14 is a primary gear segment 12 having primary gear teeth 13 extending throughout an arc. The primary gear segment 12 is fixed with respect to the activation arm 11 so as to pivot in unison therewith. Also mounted within the toaster is a carriage arm 16 extending from pivot axis 18. Attached to the carriage arm 16 is a secondary gear 15 having an arc of teeth in mesh with teeth 13 of the primary gear segment 12. At the distal end of carriage arm 16, there is an intermediate link 19 attached pivotally thereto. The distal end of intermediate link 19 would be affixed pivotally to a vertically moving bread-support carriage of the toaster. As can be understood from the figure, a small downward
displacement of activation bar 10 will result in a large vertical displacement of the intermediate link 19. As shown in Fig. 6, there is a torsion spring 60 having numerous coils surrounding pivot axis 14. The torsion spring 60 has a first leg 61 bearing against a fixed point 62 within the toaster. A second leg 63 is captured beneath the activation arm 11 and biases it upwards. There are numerous windings in the torsion spring coil between legs 61 and 63 meaning that minimal downward force on the activation bar is required.
As shown in Fig. 2, there is a horizontally movable heating element 20 positioned opposite a fixed heating element 25. The space between the heating elements receives bread for toasting. The bread- support carriage (not shown) is at the bottom of this space.
Near the bottom of the toaster, there is a horizontal pivot 22 from which there extends a first arm 21. An electric motor (not shown) would drive the horizontal pivot 22 to effect an acute angular movement of the first arm 21 to move the heating element 20 toward the fixed heating element 25. The distal or top end 23 of the first arm 21 attaches to the moving heating
element 20. There is a second arm 26 forming a parallelogram linkage with the first arm 21. The respective top ends of the first and second arms 21 and 26 are connected to one another by a top link 29 (Fig. 3) . There is a plate 27 into which there is formed an arcuate slot 24 along which a pin at the distal end 23 of the first arm 21 is guided. A clamp 28 is mounted pivotally at 29' to the second arm 26 and serves to return the movable heating element 20 to its rest position after toasting.
A torsion spring 30 has windings surrounding the horizontal pivot 22 at the bottom of the first arm 21. The torsion spring 30 has a leg 30 bearing against a fixed part of the toaster and a leg 31 having a foot 32 that bears against the front edge of the first arm 21. Because the coil spring has numerous windings between the legs 31 and 33, it provides a constant light biasing force on the first arm 21. This in turn produces a constant light force upon the heating element 20, which thereby presses lightly against a piece of bread with constant pressure. Angular movement of the first arm is caused by the motor. For closing the heating upon a piece of bread, the motor will drive and then allow the clamp to move backwards. The heater will close by action of the torsion spring,
whereas the clamp is used only to bias the heater back to its rest position and to hold it in that position. The multiple windings on the torsion spring not only provide constant force as described above, but also ensures smooth and even movement of the heating element.
As evident in Figure 2, the distal end 23 of the first arm is attached to the moving heating element 20 at a vertical mid-location. This results in a substantially even force distribution across the entire surface area of the heating element against the bread.
Figs. 4 and 5 depict a mechanism that maintains a substantially vertical orientation of the movable heating element 20 throughout pivotal translation of the first arm 21. As seen in these figures, the movable heating element 20 is mounted upon a mounting plate 50 from which there extends a shaft 51. The shaft 51 extends into a bushing 52 that is fixed upon a lever 56. The lever 56 extends from pin 23 at the upper end of the first arm 21. The shaft 51 and bushing 52 cannot rotate with respect to the heating element 20 or the lever 56. Projecting from the lever 56 is a boss 53. This boss projects through an
enlarged boundary aperture 54 in the top link 29. A leaf spring or spring wire 55 surrounds the pin 23 and has a pair of legs each having an end 57 captured by the top link 29. A mid-portion of each leg of the leaf spring engages the lever 56 and thereby maintains a substantially horizontal orientation of the lever. As the lever is fixed with respect to the heating element 20, the heating element maintains a substantially vertical orientation.
It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, a movement amplification mechanism might employ levers instead of gear segments.