IP Library Granted Patent US 12,420,140
Granted Patent B2
US 12,420,140 · App. 18/540,406 · Granted Sep 23, 2025

Exercise apparatuses for leg strengthening

Inventors: Evan Schraut (Anoka, MN); J P Stockton (Red Wing, MN); Adam D. Keskey (Buffalo, MN)
Assignee: Life Fitness, LLC
A63B23/0494A63B21/4047A63B2208/0214A63B2225/09
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Quick Facts
Patent No.
US 12,420,140
App. No.
18/540,406
Granted
Sep 23, 2025
Kind
B2
Abstract

An exercise apparatus for leg strengthening has a frame, a knee support for supporting a knee of a user relative to the frame, a leg brace for bracing a lower leg of the user relative to the frame, and a linkage assembly facilitating performance of a hamstring curl exercise motion wherein a chest of the user is lowered and then raised relative to the frame. The linkage assembly has a driver arm pivotably coupled to the frame and supporting the chest of the user, a loaded arm pivotably coupled to the frame above the driver arm and providing or supporting a load, and a connecting arm pivotably coupling the driver arm to the loaded arm so that lowering of the chest during the hamstring curl exercise motion is resisted by the load and so that raising of the chest during the hamstring curl exercise motion is assisted by the load.

Claims (46)

1. An exercise apparatus for leg strengthening, the exercise apparatus comprising:

a frame longitudinally extending from a front to a rear, vertically extending from a top to a bottom, and laterally extending from a first side to a second side,

a knee support configured to support a knee of a user relative to the frame,

a leg brace configured to brace a lower leg of the user relative to the frame,

a linkage assembly configured to facilitate performance of a hamstring curl exercise motion in which a chest of the user is lowered and then raised relative to the frame, the linkage assembly including:

a driver arm pivotably coupled to the frame and configured to support the chest of the user,

a loaded arm pivotably coupled to the frame above the driver arm, the loaded arm providing or supporting a load, and

a connecting arm pivotably coupling the driver arm to the loaded arm so that lowering of the chest during the hamstring curl exercise motion is resisted by the load and so that raising of the chest during the hamstring curl exercise motion is assisted by the load.

2. The exercise apparatus according to claim 1 , wherein the driver arm is coupled to the frame along a driver arm pivot axis and the loaded arm is coupled to the frame along a loaded arm pivot axis located above the driver arm pivot axis.

3. The exercise apparatus according to claim 2 , wherein the loaded arm pivot axis is located rearwardly of the driver arm pivot axis.

4. The exercise apparatus according to claim 2 , wherein the connecting arm is coupled to the driver arm and the loaded arm rearwardly of the driver arm pivot axis.

5. The exercise apparatus according to claim 2 , wherein the connecting arm is coupled to the driver arm along a lower connecting arm pivot axis located rearwardly of the driver arm pivot axis and the connecting arm is coupled to the loaded arm along an upper connecting arm pivot axis located rearwardly of the loaded arm pivot axis.

6. The exercise apparatus according to claim 5 , wherein the loaded arm includes an elongated member and a standoff extending upwardly from the elongated member, the upper connecting arm pivot axis extending through the standoff.

7. The exercise apparatus according to claim 2 , wherein the driver arm includes a front portion extending forwardly of the driver arm pivot axis and configured to support the chest of the user, and a rear portion extending rearwardly of the driver arm pivot axis and coupled to the loaded arm via the connecting arm.

8. The exercise apparatus according to claim 7 , wherein the connecting arm includes a lower portion coupled to the rear portion of the driver arm and an upper portion coupled to the loaded arm.

9. The exercise apparatus according to claim 7 , wherein the loaded arm includes a forward portion pivotably coupled to the frame and a rearward portion providing or supporting the load, and wherein the connecting arm is coupled to the loaded arm between the forward portion and the rearward portion of the loaded arm.

10. The exercise apparatus according to claim 7 , further including a standoff extending upwardly from the loaded arm, the connecting arm being coupled to the loaded arm via the standoff.

11. The exercise apparatus according to claim 2 , wherein the driver arm pivot axis is located longitudinally in line with the knee support relative to the frame.

12. The exercise apparatus according to claim 11 , wherein the driver arm pivot axis is located vertically in-line with the knee support relative to the frame.

13. The exercise apparatus according to claim 2 , wherein the knee support is configured to register the knee of the user longitudinally in line with the driver arm pivot axis.

14. The exercise apparatus according to claim 13 , wherein the knee support is configured to register the knee of the user vertically in-line with the driver arm pivot axis.

15. The exercise apparatus according to claim 2 , wherein the knee support includes a groove configured to register the knee on the knee support in line with the driver arm pivot axis.

16. The exercise apparatus according to claim 1 , further including an end stop configured to prevent further lowering of the chest of the user past an end position relative to the frame.

17. The exercise apparatus according to claim 16 , wherein the end stop includes a bumper, the driver arm configured to engage the bumper when the chest of the user is lowered to the end position.

18. The exercise apparatus according to claim 17 , wherein the end stop is located relative to the driver arm so that the end stop is visible to the user as the chest of the user is lowered to the end position.

19. The exercise apparatus according to claim 1 , further including a chest pad for engaging the chest of the user, the chest pad being supported on the driver arm by an adjustment mechanism that facilitates adjustment of a position of the chest pad relative to the driver arm to accommodate use of the exercise apparatus by different users of different body sizes.

20. The exercise apparatus according to claim 1 , wherein the leg brace is repositionable relative to the frame to accommodate use of the exercise apparatus by different users having different body sizes.

21. The exercise apparatus according to claim 20 , wherein the leg brace is coupled to the frame by a weldment configured to be secured to the frame in a first orientation accommodating a first body size of the user and a second orientation accommodating a different, second body size of a different user.

22. An exercise apparatus for leg strengthening, the exercise apparatus comprising:

a frame longitudinally extending from a front to a rear, vertically extending from a top to a bottom, and laterally extending from a first side to a second side,

a knee support configured to support a knee of a user relative to the frame,

a leg brace configured to brace a lower leg of the user relative to the frame,

a linkage assembly configured to facilitate performance of a hamstring curl exercise motion in which a chest of the user is lowered to a lowest position and then raised again relative to the frame, the linkage assembly configured such that a resulting force applied to the chest of the user in the lowest position corresponds to a ratio of a resistance load provided by the linkage assembly to the resulting force, the linkage assembly including:

a driver arm pivotably coupled to the frame and configured to support the chest of the user, and

a loaded arm pivotably coupled to the frame above the driver arm, the loaded arm providing or supporting a load and being coupled to the driver arm so that lowering of the chest during the hamstring curl exercise motion is resisted by the load and so that raising of the chest during the hamstring curl exercise motion is assisted by the load.

23. The exercise apparatus according to claim 22 , wherein the driver arm is coupled to the frame along a driver arm pivot axis and the loaded arm is coupled to the frame along a loaded arm pivot axis located above the driver arm pivot axis.

24. The exercise apparatus according to claim 23 , wherein the loaded arm pivot axis is located rearwardly of the driver arm pivot axis.

25. The exercise apparatus according to claim 22 , further including a connecting arm pivotably coupling the driver arm to the loaded arm so that lowering of the chest during the hamstring curl exercise motion is resisted by the load and so that raising of the chest during the hamstring curl exercise motion is assisted by the load.

26. The exercise apparatus according to claim 25 , wherein said driver arm is coupled to the frame along a driver arm pivot axis and said connecting arm is coupled to the driver arm and the loaded arm rearwardly of the driver arm pivot axis.

27. The exercise apparatus according to claim 25 , wherein said driver arm is coupled to the frame along a driver arm pivot axis, said connecting arm is coupled to the driver arm along a lower connecting arm pivot axis located rearwardly of the driver arm pivot axis, and said connecting arm is coupled to the loaded arm along an upper connecting arm pivot axis located rearwardly of the loaded arm pivot axis.

28. The exercise apparatus according to claim 22 , wherein said loaded arm is coupled to the frame along a loaded arm pivot axis and said knee support is configured to register the knee of the user longitudinally in line with the driver arm pivot axis.

29. The exercise apparatus according to claim 28 , wherein the knee support is configured to register the knee of the user at least one of vertically in-line with the driver arm pivot axis and horizontally in-line with the driver arm pivot axis.

30. The exercise apparatus according to claim 22 , further including an end stop configured to prevent further lowering of the chest of the user past an end position relative to the frame.

31. The exercise apparatus according to claim 22 , wherein said ratio of the resistance load provided by the linkage assembly to the resulting force is at least fifty percent.

32. The exercise apparatus according to claim 31 , wherein said ratio of the resistance load provided by the linkage assembly to the resulting force is at least eighty percent.

33. The exercise apparatus according to claim 32 , wherein said resulting force applied to the chest of the user is substantially equal to the resistance load provided by the linkage assembly.

Assignments (2)
SECURITY INTEREST Recorded Aug 5, 2025
From: LIFE FITNESS, LLC
To: TCW ASSET MANAGEMENT COMPANY LLC, AS COLLATERAL AGENT
Reel/Frame 072353/0574 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 18, 2023
From: SCHRAUT, EVAN; STOCKTON, JP; KESKEY, ADAM D.
To: LIFE FITNESS, LLC
Reel/Frame 065897/0243 →
Continuity (1)
Related Publication 20250195948A1 · Jun 19, 2025
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Cited By (1)
US 1,144,675