SANAA
UREMBO NA USTAWI
UJANJA
UTAMADUNI NA HISTORIA
BURUDANI
MAZINGIRA
CHAKULA NA VINYWAJI
UHANDISI WA KINYUME
SAYANSI
MICHEZO
TEKNOLOJIA
VAZI

The Lever-and-Stirrup Bootjack: One Pull Holds Toe and Heel
A plain bootjack grips only the heel, so a tight boot rocks forward and has to be held down with the other foot.
Sardis Thomson of Hartsville, Massachusetts, received US 8,865, dated 6 April 1852, for a boot-jack with "a movable heel-gripper sliding in a stand connected with a toe stirrup and lever by a connecting rod, which stirrup when the foot is placed upon the stand is drawn over the toe by the lever, at the same time drawing the heel gripper forward, and crowding the foot forward in the stirrup, thereby confining the boot in the machine".
This rung works out the lever's pull on the heel gripper, then builds the jack from board, dowel and flat bar and times taking a boot off.
Kati
About 4 hours
Maagizo
1
1
Lever force on the heel gripper
Lever force on the heel gripper
Inapakia daftari la Jupyter…
2
2
Why the long handle
Why the long handle
The embedded blueprint works out the lever law. Thomson's long handle and short rod arm put a strong, short push on the heel.
3
3
Read US 8,865
Read US 8,865
"The construction is as follows, A is the stand on which the foot is placed, B is the sliding heel gripper, which has play backward and forward in the slot C, the stirrup D extends below the stand forming in connection with the handle staff E a lever, having the fulcrum at F, and is connected with the heel gripper by the connecting rod G."
"It will be seen that the heel-gripper may be made stationary and the connecting rod G dispensed with, and the foot placed upon the stand and drawn back against the heel-gripper, and the stirrup operated as above described; but I prefer the movable gripper and connecting rod as making a more perfect apparatus."
4
4
Build the jack and take a boot off
Build the jack and take a boot off
**Stand.** Saw a board 45 × 12 cm from hardwood board. Rout or saw a slot 1 cm wide and 12 cm long down its middle, starting 15 cm from the back end. Screw a block across the back end as the rest for the other foot.
**Heel gripper.** Cut a hardwood block 10 × 6 × 4 cm, cut a curved notch in its front for the heel, and hold it on the stand with a bolt through the slot so it slides.
**Stirrup and lever.** Bend 40 cm of 25 × 3 mm mild steel flat bar into a U wide enough to pass over a boot's toe. Bolt its two ends to the sides of the stand's front end so it swings: that is the fulcrum. Bolt 80 cm of wooden dowel to the top of the U as the handle.
**Rod.** Join the U, 5 cm below its pivot, to the gripper's bolt with 35 cm of steel rod, bent into an eye at each end, so drawing the handle back pulls the stirrup over the toe and pushes the gripper forward.
**Test.** Wearing a rubber boot, put it on the stand and draw the handle back; hook the spring scale to the handle once to read your pull. Time taking the boot off, and compare with a plain boot jack.
Vifaa kwa hatua hii:
Ubao wa Mti Mgumu1 kipande
Kipande cha mbao ngumu1 kipande
Pau Bapa la Chuma Laini0.4 mita
Kigingi cha mbao0.8 mita
Ufito wa chuma laini0.35 mita
Mkusanyiko wa bolti za pembe sita1 kipande
Nati ya pembe sita4 vipande
Washa bapa6 vipande
Parafujo za mbao4 vipandeZana zinazohitajika:
Msumeno wa mkono
Msumeno wa kukata mikunjo
Kekee cha Betri
Seti ya vichimbuzi
Kibano cha meza ya kazi
Nyundo
Koleo lenye Ncha za Duara
Spana inayoweza kurekebishwa
Seti ya bisibisi
Kipima-nguvu (mizani ya springi)
Saa ya kupima muda
Buti za mpira
Kivua buti5
5
A jack that binds, slips or will not hold the toe
A jack that binds, slips or will not hold the toe
Lever-and-stirrup bootjack troubleshooting.
Flow
Loading...
6
6
History and honest limits
History and honest limits
**Sardis Thomson** of Hartsville, Berkshire County, Massachusetts, received US 8,865, dated 6 April 1852. The lever was thrown forward at about sixty degrees to start, the other foot rested on a projection at the back, and he noted that the gripper could be made fixed if simplicity mattered more than grip. His claims cover the heel gripper and stirrup worked by the lever, and the movable gripper with its connecting rod.
**Honest limits.** Board, flat bar, dowel and steel rod stand in for his cast stand, stirrup and staff. The notebook ignores friction and the rod's angle; its pull and lengths are examples. Your times are the result.
Vifaa
9- 1 kipandeKishikilia Nafasi
- 1 kipandeKishikilia Nafasi
- 0.4 mitaKishikilia Nafasi
- 0.8 mitaKishikilia Nafasi
- 0.35 mitaKishikilia Nafasi
- 1 kipandeKishikilia Nafasi
- 4 vipandeKishikilia Nafasi
- 6 vipandeKishikilia Nafasi
- 4 vipandeKishikilia Nafasi
Zana Zinazohitajika
13- Kishikilia Nafasi
- Kishikilia Nafasi
- 1 vendor sell this, none ship to you yetKishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
Mchoro huu unatengeneza
Blueprint zinazohusiana
Blueprint hizi zinashiriki maarifa — mbinu, vifaa au kanuni
CC0 Umma Wote
Mchoro huu umetolewa chini ya CC0. Uko huru kunakili, kubadilisha, kusambaza, na kutumia kazi hii kwa madhumuni yoyote, bila kuomba ruhusa.
Saidia Mtengenezaji kwa kununua bidhaa kupitia Mchoro wao ambapo wanapata Kamisheni ya Mtengenezaji iliyowekwa na Wachuuzi, au unda marudio mapya ya Mchoro huu na uiunganishe kama kiungo katika Mchoro wako kuchangia mapato.



